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Researchers from the University of Ljubljana in Slovenia pooled 72 randomized controlled trials, with 3,357 participants, that compared aerobic training against no exercise. They focused on brachial-artery flow-mediated dilation (FMD), an ultrasound test of how well an artery widens in response to increased blood flow. Programs lasting 4 to 26 weeks raised FMD by 2.35 percentage points on average. After adjusting for likely missing small negative studies, the gain was 1.74 points. The authors translate this, using observational data, into a roughly 24 percent lower risk of future cardiovascular events. Exercise also improved fitness, blood pressure, insulin resistance, lipids, CRP and body fat. Trials that produced more weight loss, fat loss, blood pressure reduction or VO2max gain tended to show larger FMD gains.

The lining of your blood vessels, the endothelium, is easy to overlook. It is a single layer of cells, yet it decides how readily arteries relax, how sticky their walls become and how they respond to blood pressure. When it falters, heart attacks and strokes tend to follow years later. A new meta-analysis asks how much aerobic exercise can do for this lining, and which other changes travel with the improvement.

The team, from the University of Ljubljana, gathered 72 randomized trials in which adults did aerobic training such as walking, cycling, running or interval sessions, while a comparison group did not. Every trial measured flow-mediated dilation. In this test, a blood pressure cuff briefly cuts off blood flow to the forearm, and ultrasound then records how much the brachial artery widens once the cuff is released. A bigger widening means a healthier endothelium.

Across the trials, exercise raised FMD by about 2.4 percentage points relative to no exercise. That may sound small, but typical values in middle-aged adults sit only in the mid-single digits, so it is a meaningful shift. Earlier observational studies link each one-point rise in FMD to roughly 8 to 13 percent fewer cardiovascular events. On that basis, the authors estimate a risk reduction of about 24%

Exercise did more than that. Fitness, measured as VO2max, rose substantially. Blood pressure, insulin resistance, blood sugar, triglycerides, LDL cholesterol and CRP all fell modestly. Body fat dropped even though none of these trials involved dieting, although body weight barely moved. Blood markers of nitric oxide, the main molecule behind artery relaxation, rose sharply.

The novel part is the meta-regression, which tests whether trials with bigger changes in one measure also showed bigger changes in FMD. The answer was yes for weight loss, fat loss, blood pressure reduction and fitness gains. The authors read this as evidence that these adaptations work together, with body composition leading the way.

That interpretation needs care. The comparison is between trials, not within individuals. Trials where people trained harder or more consistently would be expected to improve on everything at once, so the links may reflect training dose more than any specific pathway.

The pooled numbers carry other caveats. Results differed enormously between trials, with about 90 percent of the variation reflecting real differences rather than chance. Small positive trials appear overrepresented. The largest trials tended to show the smallest effects. Several studies contributed multiple exercise groups compared against the same control group, which can make the evidence look more precise than it is. Most participants already had cardiovascular or metabolic disease, and only 17 trials studied healthy people.

Still, the core message is solid and familiar. Aerobic training reliably improves the function of your arteries, and the people who gain the most fitness and lose the most fat are likely to see the largest benefit.

Actionable Insights

  1. Aerobic training improves artery function. The average gain in FMD was 2.35 percentage points, or about 1.7 after correcting for publication bias. Both figures exceed the 1-point threshold usually considered clinically meaningful. Programs ran 4 to 26 weeks.
  2. Fitness is the most useful thing to track. VO2max rose by a standardized effect of 0.81, meaning the average trained participant ended up fitter than about 79 percent of controls. Trials with bigger fitness gains also showed bigger FMD gains.
  3. Expect modest metabolic benefits. Insulin resistance (HOMA-IR) improved by an effect of 0.54, so the typical trainee did better than about 71 percent of controls. Blood pressure improved by about 0.35 to 0.41, a small but real effect, and CRP by 0.36.
  4. Exercise alone barely changes body weight, with an effect of minus 0.13, which is trivial. Body fat percentage fell more, by 0.36. Trials with more fat loss saw larger FMD gains, so pairing training with fat loss is sensible.
  5. The roughly 24 percent risk reduction is a projection from observational data. A more conservative estimate is around 17 to 22 percent, and it has not been confirmed with actual event outcomes.

Bottom line for biohackers

Aerobic training improving endothelial function is one of the most robust findings in exercise physiology, and this review confirms it with a realistic gain of about 1.7 to 2.4 FMD points. Practically, measure what you can track reliably at home or in a clinic: VO2max or a validated estimate, blood pressure, waist circumference or body fat, and fasting insulin or HOMA-IR. Push VO2max, since it is the lever most consistently tied to cardiovascular and all-cause outcomes elsewhere.

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Researchers from the Chinese University of Hong Kong analyzed retinal OCT scans from 28,657 UK Biobank participants aged 40 to 69 and compared them with each person’s Brain Care Score, a 19-point index of modifiable factors including blood pressure, HbA1c, cholesterol, BMI, diet, alcohol, smoking, physical activity, sleep, stress and social relationships. Higher scores were associated with slightly thicker retinal nerve fiber, ganglion cell and photoreceptor layers and with a retina that appeared marginally younger than expected for age. Exploratory blood metabolomic analyses in 14,656 participants suggested lipid, omega-3 and branched-chain amino acid patterns statistically accounted for a small share of these links.

The back of your eye is a piece of brain you can photograph. The retina develops from the same embryonic tissue as the brain, and its nerve layers thin with age, with diabetes and high blood pressure, and in people heading toward dementia. That makes it a cheap, non-invasive window onto how well the nervous system is aging.

A team led by ophthalmologists at the Chinese University of Hong Kong used that window to test the Brain Care Score, a checklist developed at the McCance Center for Brain Health in Boston. The score awards points for healthy blood pressure, blood sugar, cholesterol and body weight; for diet, alcohol, smoking, exercise and sleep; and for low stress and good social relationships. Higher scores have previously been linked to healthier brain scans and lower risk of stroke, dementia and late-life depression.

The researchers analyzed retinal scans from 28,657 UK Biobank volunteers. People with higher scores had slightly thicker retinas in the layers most relevant to neurodegeneration: the nerve fiber and ganglion cell layers, which carry visual signals to the brain, and parts of the photoreceptor layer, which captures light. Every 5-point improvement on the 19-point scale went with about one micron more overall macular thickness.

The team also used a machine learning model to estimate each person’s “retinal age” from 60 scan measurements. A 5-point better score went with a retina that looked about four months younger than expected. Blood pressure, blood sugar and body weight drove most of the link. Not smoking, moderate drinking, exercise and at least seven hours of sleep added smaller contributions. Stress and social relationships showed nothing.

Blood chemistry hinted at why. In participants with metabolic profiling, patterns of circulating fats, including HDL subtypes, large triglyceride-rich particles, omega-3 fatty acids and branched-chain amino acids, statistically accounted for a small slice of the association, typically under 10 percent.

The size of these effects matters. One micron is about one seventieth the width of a human hair, smaller than the variation between repeat scans of the same eye. The authors themselves say the differences cannot be seen in an individual. Four months of retinal age is small next to the model’s average error of almost six years. The retinal age model is also weak: it tracked real age only modestly, and people with diagnosed heart disease, stroke or diabetes had retinas that looked just 0.2 years older than healthy people.

The design limits what can be concluded. Everything was measured at a single point in time, so the study cannot show that improving your score thickens your retina or slows its aging. The metabolite analyses are statistical decompositions of snapshot data, not proof that blood lipids carry the effect. And because cholesterol and blood sugar sit inside both the score and the blood panel, some overlap is built in.

What the study does show is consistency. Across tens of thousands of people, the same vascular and metabolic factors that predict brain health also track with a slightly healthier-looking retina. That supports the idea of the eye as a mirror of the brain, and gives researchers a reason to test retinal scans as a cheap readout in lifestyle and drug trials.

Actionable Insights

This study tested no intervention. It describes which everyday factors line up with retinal structure.

  1. Prioritize the physical numbers. Optimal blood pressure, HbA1c and BMI each went with a retina appearing roughly 3 to 5 months younger (0.25 to 0.45 years). These were the strongest single factors.
  2. Lifestyle adds a little. Not smoking, moderate alcohol, regular aerobic exercise and at least 7 hours of sleep each corresponded to about 1 to 2 months younger retinal age (0.08 to 0.15 years).
  3. Stress and social measures showed no retinal association in this dataset.
  4. Keep magnitudes in perspective. Moving from the bottom to the top quarter of brain care scores corresponded to about 1.5 microns more macular thickness (about half a percent) and a retina looking 0.39 years younger. In statistical terms that is roughly a tenth of a standard deviation, a very small effect. It matters for populations, not for reading your own scan.
  5. The omega-3 (DHA) link to photoreceptor thickness is a hypothesis, not a recommendation.

Context and Source

  • Open Access Paper: Brain care score and retinal health: structural and metabolic insights from the UK Biobank
  • Institutions: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong; Hong Kong Eye Hospital; Prince of Wales Hospital; Sichuan Provincial People’s Hospital and University of Electronic Science and Technology of China (Chengdu)
  • Country: China (Hong Kong SAR and Sichuan). Data from the United Kingdom.
  • Journal: GeroScience (Springer), official journal of the American Aging Association.
  • Impact evaluation: The impact score of this journal is 4.9 (2024 Journal Impact Factor; CiteScore 8.3), evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Medium impact journal. Within aging-specific journals it sits in the top quartile.

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Researchers from the University of South Carolina and the Icelandic Heart Association used structural MRI scans from 4,606 older Icelanders (average age 76) to estimate each person’s “brain age,” then compared it with their actual age. People whose brains looked older than their years scored lower on memory, processing speed and executive function tests, independent of age, sex and education. In the 2,561 participants retested about five years later, an older-looking brain predicted slightly faster memory decline, but not faster decline in processing speed or (in the main model) executive function. The authors propose the brain age gap as a biomarker for preventive care, although the longitudinal effect was small and only marginally significant.

Two 75-year-olds can have very different brains. One may show the shrinkage typical of someone a decade older, while the other looks closer to 65. A new analysis of the long-running AGES-Reykjavik Study asks whether that difference, called the brain age gap, tells us anything about where a person’s thinking skills are headed.

The team took MRI scans collected between 2002 and 2006 from 4,606 Icelanders born between 1907 and 1935. An automated tool called volBrain estimated each person’s brain age from the structure of their brain. Subtracting real age from brain age gave the gap. A positive gap means the brain looks older than expected; a negative gap means it looks younger. In this group the average gap was about two years on the young side, with individuals ranging from roughly 19 years younger to 11 years older.

The first finding was clear and consistent. People with older-looking brains performed worse across all three areas of thinking tested: memory, processing speed and executive function, the set of skills used for planning, juggling information and switching tasks. Each additional year of brain age gap was linked to a cognitive deficit roughly equal to one year of ordinary aging for memory, and a bit less for processing speed.

The bigger question was whether brain age predicts the future. About five years later, 2,561 participants returned for testing. Everyone declined, as expected in this age group. People with older-looking brains lost memory slightly faster than others. A ten-year difference in brain age gap translated into about 30 percent more memory decline over five years. Grouping participants by their gap, the researchers also saw steeper drops in executive function among those whose brains looked older. Processing speed, by contrast, declined at much the same rate regardless of brain age.

The authors argue that this makes brain age useful as an early warning sign in people without obvious disease, and that it could help identify who might benefit most from attention to exercise, blood vessel health and cognitive training.

That conclusion deserves caution. The forward-looking memory effect only just crossed the conventional threshold for statistical significance, and the authors tested three areas of thinking without correcting for multiple comparisons. The study did not test any treatment, did not measure whether brain age itself changed, and did not account for blood pressure, diabetes, smoking or genetic risk. The participants were Icelandic, white, and assessed nearly two decades ago, and many dropped out before the second visit, often for reasons such as illness or death that are themselves tied to brain aging.

Still, the result adds a piece to a growing picture. A large body of earlier work shows that older-looking brains go with poorer thinking at a single point in time. Some researchers have argued that this mostly reflects differences fixed early in life rather than ongoing aging. A brain age gap that predicts future memory loss, even modestly, suggests the measure captures some of the active process too. Whether anyone can move that number, and whether moving it protects memory, remains the question that matters most.

Actionable Insights

This is an observational study. It tested no treatment, so its practical value is mainly in interpreting a brain age result.

  1. Reading a brain age report. In this cohort, each year your brain looks older than your birthday corresponded to roughly the memory deficit of one extra year of normal aging (0.047 standard deviations per brain-age year, versus 0.046 per calendar year of observed decline). A brain looking 5 years older equals about a quarter of a standard deviation lower memory score: real but modest, the gap between an average performer and someone around the 40th percentile.
  2. What to do about it, or how to avoid it. The authors point to physical activity, vascular health and cognitive training. The strongest outside evidence is for blood pressure control: in the SPRINT MIND trial, intensive control lowered mild cognitive impairment risk by about 19 percent.
  3. Treat an “old” brain age as a prompt to check blood pressure, glucose, sleep and activity, not as a diagnosis.

Context and Source

  • Open Access Paper: Advanced brain age and longitudinal cognitive decline in healthy older adults
  • Institutions: University of South Carolina (Departments of Communication Sciences and Disorders, Psychology, Neurology; Arnold School of Public Health); Icelandic Heart Association
  • Countries: United States and Iceland
  • Journal: GeroScience (Springer), official journal of the American Aging Association.
  • Impact evaluation: The impact score of this journal is 4.9 (2024 Journal Impact Factor; CiteScore 8.3), evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Medium impact journal. Within aging-specific journals it sits in the top quartile.

Leitura Relacionada:

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The American College of Sports Medicine has replaced its 2009 resistance training guidelines with an evidence-graded umbrella review of 137 systematic reviews covering more than 30,000 adults. Almost every form of resistance training beat doing nothing, improving strength, muscle size, power, endurance, gait speed, balance and functional tests. Only a few programming variables changed results: heavier loads, full range of motion, multiple sets and twice-weekly frequency for strength; higher weekly volume and eccentric emphasis for muscle size; moderate loads lifted fast for power. Training to failure, equipment choice, rep speed, rest intervals and periodization did not consistently matter. The headline recommendation is effortful training of all major muscle groups at least twice a week, in whatever format a person will stick with.

For 17 years, the official American College of Sports Medicine advice on strength training read like a technical manual: two to three sessions a week, eight to ten exercises, one to four sets of eight to twenty reps, set rest periods, loads between 40 and 70 percent of your one-rep maximum, and a periodized plan to tie it together. Critics argued that much of this rested on thin evidence. One recommendation graded as top-quality evidence turned out to rest on three small studies with 59 people in total. The new position stand, led by Brad Currier and Stuart Phillips at McMaster University, replaces the manual with a simpler message: the biggest gain comes from going from no resistance training to some.

The team pooled 137 systematic reviews of randomized trials lasting 6 to 52 weeks. Compared with doing nothing, resistance training reliably improved strength, muscle size, power, endurance, contraction speed, walking speed, balance, chair-stand performance and the timed up-and-go test. That held for machines, free weights, circuits, elastic bands and home programs alike.

The more provocative findings are about what didn’t matter. Training to complete muscular failure, machines versus free weights, fast versus slow reps, time under tension, short versus long rest, morning versus evening sessions and elaborate periodization schemes did not consistently change outcomes. Many of these are staples of gym culture and fitness marketing.

A handful of levers did move results. For maximal strength: heavier loads of around 80 percent of one-rep max or more, full range of motion, two to three sets, at least two sessions a week, and doing the key lift early in the session. For muscle size: more weekly volume, roughly 10 or more sets per muscle group, plus emphasis on the lowering phase of each rep. For power: moderate loads moved fast, Olympic-style lifts and modest volume. Power training, where the lifting phase is done as quickly as possible, also stood out for improving walking performance and the Short Physical Performance Battery, measures that matter for independence in later life.

The longevity angle is participation rather than optimization. Only about 30 percent of American adults report doing muscle-strengthening work twice a week, and close to 60 percent do none. The authors note that following the old guidelines fully could, in some cases, demand 20 hours a week.

There are real limits. An umbrella review counts how many reviews found an effect rather than pooling raw data, so it tells you whether a variable matters more than how much. Most underlying trials used untrained volunteers over a few months, and beginners respond to almost any stimulus, which flatters the “anything works” conclusion. Overlap between reviews was checked only for strength. And the outcomes are surrogates such as muscle size and one-rep max, not death or disability. The connection to lifespan comes from separate observational studies linking muscle-strengthening activity to 10 to 17 percent lower risk of death and major chronic disease, data that cannot fully exclude healthier people simply being the ones who lift.

Still, the direction is clear and well supported. For most adults, consistency beats cleverness.

Actionable Insights

Train all major muscle groups at least twice a week. In the same group’s earlier analysis of nearly 200 trials, a heavier, multi-set, twice-weekly program produced a muscle-growth effect size of 0.66 versus no training. In plain terms, the average trainee gained more muscle than about 75 percent of people who didn’t train. Every program tested beat doing nothing.

For muscle size, aim for 10 or more hard sets per muscle per week. One dose-response analysis found fewer than 5 weekly sets produced about 5.4 percent growth, while 10 or more produced about 9.8 percent, roughly 0.37 percent extra per added weekly set. Returns flatten somewhere around 18 to 20 sets.

For strength, use heavier weights (around 80 percent of your max, a weight you can lift roughly 8 to 10 times), 2 to 3 sets per exercise, through full range of motion.

For function as you age, add fast lifting with moderate loads (30 to 70 percent of max).

Stop 2 to 3 reps short of failure. Going all the way added no measurable benefit.

The lifespan payoff: cohort data link 30 to 60 minutes a week of strength work with 10 to 20 percent lower risk of death. For someone with a 10 percent ten-year risk, that is roughly 1 to 2 percentage points. That’s an association, not proof.

Context and Source

  • Open Access Paper: American College of Sports Medicine Position Stand. Resistance Training Prescription for Muscle Function, Hypertrophy, and Physical Performance in Healthy Adults: An Overview of Reviews.
  • Institution and country: Department of Kinesiology, McMaster University, Hamilton, Canada (lead and corresponding). Co-authors are from the University of Sydney (Australia), University of Toronto (Canada), and US institutions including Hebrew SeniorLife’s Marcus Institute for Aging Research, UNC Chapel Hill, Penn State, CUNY Lehman College, Appalachian State, University of Arkansas, Salisbury University and Messiah University.
  • Journal: Medicine & Science in Sports & Exercise
  • Impact evaluation: The impact score of this journal is 3.9 (Journal Impact Factor, 2025 JCR release; 5-year JIF 5.2; CiteScore 8.6), evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Medium impact journal.

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In a Nature Comment, four researchers from Harvard/Mass General Brigham, Aarhus, Yale and Scripps argue that medicine has no routine way to measure immune health. A white cell count and C-reactive protein say little about whether a person’s defenses are strong, declining, or aging faster than they are. They propose building the “immunome,” a full map of immune cells, proteins, receptors, organs and responses to challenges like vaccination. That data would then be cut down to a small, cheap, validated panel that could guide prevention, vaccination and cancer immunotherapy. The piece presents no new data. It rests on recent work, much of it from the authors’ own groups, including AI scoring of the thymus on CT scans and a machine-learning “immune health metric.”

Ask a doctor how healthy your heart is and you get numbers: blood pressure, cholesterol, maybe a stress test. Ask how healthy your immune system is and you mostly get a shrug. A white blood cell count and a C-reactive protein reading are about the extent of it. Neither tells you whether your defenses are robust, failing quietly, or aging faster than the rest of you.

In a Comment piece in Nature, Hugo Aerts, Nicolai Birkbak, John Tsang and Eric Topol argue that this gap can now be closed. They propose building the “immunome,” a full description of immune health spanning cells, proteins, organs and their interactions. That description would then be distilled into a few inexpensive tests a clinic could actually run.

The premise rests on growing evidence that people of the same age carry very different immune systems. Genes, smoking, air pollution, diet and past infections all shape them. The biological age of the immune system also tracks with risk of cancer, neurodegeneration and death.

Several recent tools hint at what a clinical readout might look like. An AI system that grades the thymus on routine chest CT scans found that adults with a healthier-looking thymus had roughly half the death rate over 12 years. A machine-learning score built from people with rare inherited immune disorders also picked up immune dysfunction in common autoimmune disease. The same score predicted how well older adults respond to vaccines. Separately, proteomic clocks can estimate immune age from blood proteins.

The road map has three stages. First, collect deep, repeated measurements in large and genetically diverse populations, including before and after vaccination, which works as a standardized stress test of immune competence. Second, simplify: find the smallest set of measurements that still captures meaningful differences, and prove across many hospitals that acting on them improves decisions. Third, set rules on consent, privacy and discrimination before anything goes mainstream. An immune profile, like a genome, could reveal future disease risk. Unlike a genome, it changes over time.

The authors offer an analogy. Blood pressure does not describe the whole cardiovascular system, and glucose does not capture all of metabolism, yet both are indispensable. An immune equivalent may need several numbers rather than one.

The weak points are real, and the authors acknowledge some of them. AI models trained on thousands of immune variables can learn differences between labs, scanners and populations as easily as differences in biology. Most immune-profiling data come from wealthy countries.

The bigger problem is that none of the cited work shows that measuring immune health, then acting on it, improves outcomes. Blood pressure earned its place because lowering it was proven to prevent strokes. For immune health there is not yet a validated lever to pull.

Much of the highlighted evidence also comes from the authors’ own labs, including the thymus CT studies and the immune health metric. That is normal for an agenda-setting essay, but readers are hearing the case from its advocates.

Still, the direction is sound. The thymus data suggest immune aging can already be measured from scans millions of people have had. The open question is whether that number will ever change a treatment decision.

Actionable Insights

This is an opinion piece, so it tests no intervention. The useful numbers come from the studies it cites, especially the thymus CT work.

  • In about 25,000 lung-screening participants followed for 12 years, 13.4% of people with high thymic health died, compared with 25.5% with low thymic health.
    • That is a hazard ratio of 0.49, or roughly half the death rate.
    • In plain terms, there were about 12 fewer deaths per 100 people, or one extra survivor for every 8 people in the high group versus the low group.
  • Cardiovascular death was 2.9% versus 7.5% in the same comparison. That is an absolute gap of 4.6 points, about one fewer death per 22 people.
  • These figures compare the best and worst groups and are associations. They do not show what happens if you improve your own thymus.
  • Thymic health tracked with smoking, obesity and physical activity. Not smoking, avoiding excess body fat and staying active are the defensible moves, and they are the same advice you have already heard.
  • The authors propose vaccine response as a practical readout of immune fitness. Staying current on routine vaccines costs little.

Context and Source

  • Open Access Article: Could measuring immune health reshape medical care?
  • Article type: Comment (opinion and agenda-setting piece, not primary research)
  • Authors and institutions:
    • Hugo J. W. L. Aerts: Mass General Brigham and Harvard Medical School (USA), and Maastricht University (Netherlands)
    • Nicolai J. Birkbak: Aarhus University and Aarhus University Hospital (Denmark)
    • John S. Tsang: Yale University (USA)
    • Eric J. Topol: Scripps Research (USA), corresponding author
  • Countries: USA, Netherlands, Denmark
  • Journal: Nature, Vol 658, pp. 1128 to 1130, 29 October 2026
  • Impact evaluation: The impact score of this journal is 56.1 (2025 Journal Impact Factor, released June 2026), evaluated against a typical high-end range of 0-60+ for top general science, therefore this is an Elite impact journal.

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A Mayo Clinic team combined three lines of evidence on how insulin resistance affects the aging brain. In a cross-sectional comparison of 74 adults aged 50 to 80, people with prediabetes-range fasting glucose and overweight had lower whole-brain and hippocampal volume, less white matter, lower glucose uptake on PET, and fewer strong functional connections between frontal and limbic regions than lean, exercising controls. In young adult mice, deleting the insulin receptor in the brain lowered brain mitochondrial ATP production, raised oxidant emission and impaired short-term memory, with no change in body weight or blood sugar. In a double-blind trial, 40 older adults with presumed insulin resistance took metformin (1,500 to 2,000 mg/day, plus vitamin B12) or placebo for 40 weeks. Metformin improved glycemia and weight, increased glucose uptake in four brain regions, changed functional connectivity, and improved a post hoc processing speed and working memory score. Prespecified cognitive composites did not change.

Your brain uses about a fifth of your body’s energy, and it runs mainly on glucose. A Mayo Clinic team led by K. Sreekumaran Nair asked a simple question: what happens to that fuel supply when the body becomes resistant to insulin, as it does in many people in their 60s and 70s? Their answer, published in the Journal of Clinical Investigation, is that the brain seems to run on a slightly emptier tank, and that a cheap diabetes drug may partly refill it.

The researchers first compared 56 older adults with overweight and fasting glucose in the prediabetes range against 18 lean, regularly exercising peers. The metabolically unhealthy group had brains about 4 to 5 percent smaller relative to skull size, with the losses concentrated in white matter, the wiring that links brain regions, and in the hippocampus, a key memory hub. PET scans showed lower glucose uptake in prefrontal, parietal and cingulate areas involved in attention and working memory. Resting-state MRI showed fewer strong links between frontal regions and the brain’s default mode network.

That comparison cannot show cause and effect, especially since the healthy group was also leaner and exercised more. So the team turned to mice. They deleted the insulin receptor in the brains of young adult mice without changing their body weight or blood sugar. Brain mitochondria in these animals produced about a third less ATP, released almost twice as much hydrogen peroxide, and had less antioxidant capacity. The mice also did worse on simple maze tests of short-term spatial memory.

The final step was a randomized trial. Forty adults in their 60s with presumed insulin resistance took metformin or a placebo for 40 weeks. Everyone took vitamin B12, since metformin can deplete it and B12 deficiency harms cognition. Metformin lowered HbA1c, fasting glucose and body fat as expected. Whole-brain glucose uptake trended upward but did not reach significance. Four regions, including parts of the orbitofrontal cortex and the thalamus, showed significantly larger increases on metformin. Average cortical thickness changed by +0.44 percent with metformin versus -0.26 percent with placebo, a difference that was not statistically significant. Two visual-cortex regions did reach significance. Metformin also produced more changes in functional connectivity, centered on the executive control network.

The cognitive result needs careful reading. A combined score for processing speed and working memory improved more with metformin, by a moderate effect size. However, that composite was built after the fact. The three cognitive composites the team specified in advance showed no difference.

The study has real strengths: a placebo control, B12 supplementation that removes an important confounder, and multimodal imaging rarely combined in a single trial. It also has real limits. With only 20 people per arm, a single site, many brain regions tested and few corrections for multiple comparisons, it is best read as a well-designed pilot. The larger MAP trial, which is testing metformin in more than 300 people with mild cognitive impairment, should give a clearer verdict.

Actionable insights

This is a careful, multimodal pilot from an experienced metabolic group, with good design choices (placebo control, B12 supplementation, controlled fasting conditions). Its headline claims (“preserves structure,” cognitive benefit) run ahead of its statistical power and its post hoc cognitive endpoint. The most robust conclusions are that metformin improved glycemia and weight as expected, and that insulin resistance tracks with a less energetic, less connected brain. Whether metformin itself protects the brain remains open.

  1. Glucose control is the strongest result. In older adults with prediabetes-range blood sugar, 40 weeks of metformin produced large improvements relative to placebo: HbA1c fell by roughly 0.25 percentage points (effect size d about 1.3, large), BMI fell by about 1.2 units, or roughly 3 to 4 kg (d about 1.1), and fasting glucose dropped by about 7 mg/dL (d about 0.9).
  2. Brain effects were moderate and regional. Glucose uptake rose in four regions (d about 0.7 each), but the whole-brain change was not significant.
  3. Cognition improved on one measure that was defined after the data came in (d about 0.76). Treat this as a hypothesis, not a benefit.
  4. If you take metformin, keep vitamin B12 up. The trial supplemented everyone and kept levels above 180 ng/L.
  5. Exercise was the hidden variable. The healthy comparison group exercised at least three times a week. In a separate trial (MASTERS), 1,700 mg/day of metformin blunted lean mass gains from resistance training in adults over 65. If you lift weights, discuss this tradeoff with your clinician.

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The Dog Aging Project analyzed 41,047 US companion dogs followed for a median of about two years, with 11,739 deaths. Body size was the dominant predictor of lifespan: median survival fell from about 14 years in small mixed-breed dogs to under 9 years in giant purebred males. Within each size class, mixed-breed dogs outlived AKC-registered purebreds, and females had a small advantage, mostly in larger purebreds. After adjusting for size, breed status and sex, rural, suburban and urban differences vanished, but state-level differences remained and tracked human mortality across states (r = 0.43). A screen of 804 owner-survey variables flagged 72 associated with mortality, mostly owner-rated health, chronic disease, physical activity and energetic behavior. All findings are observational.

Dogs make useful stand-ins for people in aging research. They share our homes, our air and often our habits, they get many of the same chronic diseases, and they age about five to seven times faster. The Dog Aging Project was built to use that, and this paper is its first big look at who dies when.

The researchers followed more than 41,000 pet dogs whose owners filled in a detailed baseline survey covering health, diet, exercise, behavior and environment. Over about two years of follow-up, nearly 11,800 dogs died, most of them by euthanasia.

The headline result confirms what vets have long seen. Size dominates. Small mixed-breed dogs had a median lifespan of about 14 years. Giant purebred males reached about 9. Within every size class, however, the spread was wide. Half of the dogs in each group died within a window of roughly four years, which means size sets the average but leaves plenty of room for other factors.

Breed background mattered too. Mixed-breed dogs outlived purebreds of the same size by up to 1.6 years in males and about half a year in females, consistent with the idea that genetic diversity protects against inherited disease. Breed-level differences were stark. Dachshunds, Havanese and Border Collies reached a median of around 14 years, while Doberman Pinschers and Great Danes lived about 8.5. Cavalier King Charles Spaniels and Boxers fell well short of other dogs their size, consistent with their known heart disease burdens.

The more surprising result was geographic. Once size, breed and sex were accounted for, living in the city or the country made no difference. But some states still stood out. Dogs in Texas, Tennessee and parts of the South died sooner, while dogs in California and Washington lived longer. When the team set these state-level dog risks against human death rates, the two lined up. States where people die younger tended to be states where dogs die younger too. Something about place, whether climate, parasites, veterinary access, income or pollution, appears to affect both species.

The survey screen produced a long list of signals. Owners who rated their dog’s health as very poor were about five times more likely to lose it during follow-up than owners who rated it excellent. Dogs that walked briskly, swam, played games daily, chased squirrels and had access to parks had lower risk. Dogs that slowed down, lost appetite or started soiling the house when left alone had higher risk.

These links are easy to misread. A dog that walks slowly may already be ill, and a dog that eats grass may simply be one healthy enough to roam outdoors. The authors say plainly that their list is a set of leads for future study, not a recipe for longer life.

What the study does provide is a solid baseline. The Dog Aging Project’s data are public, the follow-up is growing every year, and the ongoing genetic, biomarker and drug-trial arms will be able to test which of these signals are causes and which are only symptoms.

Actionable insights

These are associations, so the effect sizes below describe what was observed, not what changing the factor would achieve.

  1. Breed choice carries the largest effect. A giant purebred male’s median lifespan (8.9 years) is about 4.4 years, or one-third, shorter than a small purebred male’s (13.3). Picking a mixed-breed dog of the same size was associated with 0.4 to 1.6 extra years.
  2. Treat your own impression of your dog’s health as a warning signal. Dogs rated “very poor” had 4.9 times the risk of dying compared with “excellent”. Loss of appetite (1.4 times the risk) and new house soiling when alone (about 1.35 times) were also red flags that justify a vet visit.
  3. Activity tracks with longevity. Dogs whose walks were all brisk rather than all slow had about 19 percent lower risk, and dogs that swam showed the same 19 percent reduction. If those links were fully causal, which is unlikely, that would be worth roughly six months of median life.
  4. For humans, the dog-human state correlation adds modest support to the idea that local environment, beyond personal choices, shapes lifespan.

Context and source

  • Open Access Paper: Factors associated with longevity in companion dogs: initial findings from the Dog Aging Project
  • Institutions: Texas A&M University (corresponding author), University of Washington, Tufts University (Jean Mayer USDA Human Nutrition Research Center on Aging)
  • Country: United States
  • Journal: GeroScience (Springer; official journal of the American Aging Association)
    Impact evaluation: The impact score of this journal is 5.4, evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Medium impact journal.

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Three executives from Loyal, a San Francisco company developing lifespan drugs for dogs, argue that human longevity medicine is blocked less by science than by regulation and economics. Their proposal has two parts. The first is to validate surrogate endpoints that respond quickly enough to measure, such as “intrinsic capacity” or established biomarkers like LDL cholesterol, kidney filtration and HbA1c. The second is to change the FDA’s 505(b)(2) pathway so that already-approved drugs with proven all-cause mortality benefits, chiefly GLP-1 receptor agonists and SGLT2 inhibitors, can get accelerated approval for lifespan extension while outcomes trials continue. They point to the veterinary expanded conditional approval (XCA) pathway, under which Loyal’s LOY-002 is advancing, as working precedent. The piece is an opinion commentary with no new data.

There is no approved drug for aging. The authors argue the main obstacles are not biological. They are the clock and the money.

A human trial with lifespan as its endpoint would need thousands of older participants followed for decades and would cost billions. Even if it succeeded, the sponsor would get only a short window of market exclusivity. Under those terms almost no company will run such a trial, and those with the resources to do it have little reason to try.

The authors work at Loyal, which is trying to get the first drug approved specifically to extend lifespan in any species. In dogs, a regulatory route already exists. Under 2018 legislation, the FDA’s Center for Veterinary Medicine can grant conditional approval to an animal drug when demonstrating efficacy requires long and expensive studies. A sponsor that shows safety, consistent manufacturing and a “reasonable expectation” of benefit from shorter studies (improved metabolic function, for instance) can sell the drug while the definitive trial runs. Conditional approval lasts one year and can be renewed annually for up to five years if the company shows progress.

Loyal’s lead candidate, LOY-002, is a daily pill for dogs aged 10 or older and weighing at least 14 pounds. It aims to correct age-related metabolic dysfunction. Its pivotal STAY trial has enrolled 1,346 dogs at 73 US clinics and will run at least five years, with lifespan as the primary endpoint. The FDA has accepted LOY-002’s efficacy and safety sections. Manufacturing review remains, and the company expects that in 2027.

The commentary proposes a parallel route for humans. Drugs already approved and already shown to reduce deaths from all causes in several diseases could be granted accelerated approval for lifespan or mortality reduction. Eligibility would require a good post-marketing safety record, action against common age-related changes such as insulin resistance or early atherosclerosis, and measurable biomarkers that track the drug’s effects. GLP-1 drugs such as semaglutide and SGLT2 inhibitors such as dapagliflozin are the obvious first candidates. Full approval would still depend on outcomes trials.

The proposal also depends on better ways to measure aging in people. The authors highlight ARPA-H’s PROSPR program, which funds VITAL-H. That $38 million trial will test rapamycin, dapagliflozin and semaglutide against placebo in 726 adults in their early 60s, using intrinsic capacity, a composite of physical and mental function, as the outcome.

There is a reasonable argument here. Dogs share our homes, our diets and many of our diseases, so a positive lifespan result in a diverse population of pet dogs would mean more than another mouse study. The proposal’s weaknesses are equally clear. No lifespan drug has yet received conditional approval in dogs, so the “precedent” is a process, not a result. The mortality benefits of GLP-1 and SGLT2 drugs have been shown in sick people, not healthy ones. Human medicine also has a long record of drugs that improved a biomarker while failing to improve, or even worsening, survival. The authors acknowledge some of these limits.

Actionable insights

The commentary contains no new data, so its practical value comes from the evidence it cites.

  1. In the SELECT trial, semaglutide given to people with overweight or obesity, established heart disease and no diabetes cut deaths from any cause from 5.2 percent to 4.3 percent over about three years. That is a 19 percent relative reduction, roughly 1 death prevented for every 111 people treated. Across SGLT2 inhibitor trials in diabetes, heart failure and kidney disease, the risk of death fell by about 11 to 16 percent.
  2. VITAL-H is the trial to watch. It is the first rigorous test of whether these drugs preserve function in healthy people in their 60s.
  3. Dog owners should know that LOY-002 is not yet available for commercial sale, and its effect on lifespan is still unknown.

Context and source

  • Open Access Paper: Lessons from dog lifespan therapeutics for their human companions
  • Institution: Loyal Animal Health, San Francisco, California
  • Country: United States
  • Journal: GeroScience (Springer; official journal of the American Aging Association)
  • Funding and conflicts: Funded entirely by Loyal. All three authors are Loyal employees and/or shareholders.
    Impact evaluation: The impact score of this journal is 5.4, evaluated against a typical high-end range of 0-60+ for top general science, therefore this is a Medium impact journal.

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Researchers in China exposed middle-aged mice (11 months old) to a year of rotating mild stressors, including noise, cage tilting, crowding, isolation, wet bedding, light disruption and water deprivation. Stressed mice showed higher frailty scores, poorer memory and strength, loss of muscle and fat, gut and skin damage, and higher mortality. Single-cell sequencing of brain, gut, kidney, lung and blood showed a common pattern of fewer lymphocytes (especially B cells) and more inflammatory myeloid cells, with the lung most affected. Mice given NMN or the commercial herbal formula Bazi Bushen (BZBS) from the start of the stress period fared better, with high-dose BZBS performing best. Lab experiments attributed part of the effect to compounds from Schisandra and Cnidium that bind and activate AMPK and sirtuins and protect mitochondria in stressed cells.

Stress has long been suspected of aging people faster. Studies in humans link years of chronic strain to faster-ticking epigenetic clocks and immune profiles that look older than their owners. What has been harder to show is cause, and which organs pay the price.

This study attempted both in mice. Starting at 11 months, roughly equivalent to a person in their early 40s, mice endured a year of unpredictable daily hassles: tilted cages, damp bedding, crowding, isolation, white noise, scrambled light cycles and periods without water. The stressors rotated so the animals could not adapt.

The results were stark. Stressed mice scored worse on frailty checklists, lost interest in new companions, got lost more often in a memory maze and fell off a rotating rod sooner. Their calf muscles shrank to about half normal weight, belly fat nearly vanished, intestinal villi shortened and the skin thickened. Females under stress died at six times the rate of unstressed females over the study period.

To see what was happening inside, the team sequenced nearly 300,000 individual cells from the brain, small intestine, kidney, lung and blood. A common thread emerged: stress depleted lymphocytes, particularly B cells and naive T cells, while inflammatory macrophages and neutrophils expanded. The lung showed the largest changes, leading the authors to suggest it may act as a hub where stress-driven immune aging spreads.

Two interventions, given from the start of the stress period, were tested. One was NMN, the popular NAD+ precursor. The other was Bazi Bushen, a patented Chinese formula of eight medicinal seeds and herbs, including Schisandra, Cnidium, goji, ginseng and Cistanche. Both helped. High-dose BZBS performed best, cutting the female death rate from 72 percent in stressed animals to 28 percent, and restoring much of the lost muscle, fat and gut structure.

To find out how, the researchers identified which herbal compounds reach the blood and brain of rats. They then tested those compounds in stressed brain support cells and immune cells. Compounds from Schisandra and Cnidium (schisandrin B, schisantherin A and osthole) reduced mitochondrial free radicals, preserved mitochondrial membrane potential and, in the case of osthole, improved cellular respiration. They appeared to bind AMPK, the cell’s energy sensor, and several sirtuins, and blocking AMPK erased much of their benefit. In the lungs of treated mice, AMPK activation and levels of the mitochondrial master regulator PGC-1 alpha were higher.

The story is tidy, but several details deserve caution. The unstressed male mice in this study died far earlier than healthy laboratory mice usually do. The experiment ended when the mice were 21 to 23 months old, before most would die naturally, so it measured early deaths rather than lifespan. The treatment began alongside the stress, so the study tested prevention rather than the “reversal” promised in the title. And the herbal concentrations that worked in cell dishes were far higher than blood levels normally achieved by eating the plants.

The broader message holds up better than the product claim. Sustained, unpredictable stress produced broad, measurable aging-like damage in mice, and interventions that support mitochondrial function blunted it. Whether this specific formula does anything comparable in stressed humans is entirely untested.

Actionable Insights

Sustained physiological strain acts as a major driver of biological aging, accelerating physical frailty and chronic inflammation. This research reveals that the primary systemic damage occurs via an overactive innate immune response coupled with depleted cellular energy reserves.

For educated individuals seeking healthspan optimization, the take-home message is clear: mitigating biological stress requires both lifestyle moderation and targeted cellular energy support. The study highlights that activating the AMPK-Sirtuin-PGC-1a signaling axis is vital for cellular survival under duress.

The real-world magnitude of this intervention is substantial. In stressed animal models, high-dose botanical supplementation reduced the absolute risk of premature mortality by 44 percent in males (dropping from 72 percent to 28 percent) and by 32.2 percent in females (dropping from 72.2 percent to 40 percent). This equates to a relative reduction in mortality risk of 61 percent for males and 45 percent for females under sustained strain. Physical frailty scores dropped by 41 percent, gut lining architecture was preserved by an 86 percent increase in villus height, and motor endurance improved by over 120 percent compared to untreated stressed subjects. People experiencing unavoidable occupational or psychological strain should prioritize habits and compounds that activate AMPK and maintain NAD-dependent sirtuin activity.

Do not buy Bazi Bushen on the strength of this study. The research is still early. All evidence is from mice and cell culture, run by groups tied to the product’s ecosystem. The mouse dose scales to roughly 11 g of formula per day for a 70 kg adult by standard body-surface conversion.

NMN at a mouse dose equivalent to roughly 1.1 g/day in a 70 kg human also reduced deaths (female mortality 72% down to 36%), but this was a single-dose, single-study result in an unusual model.

If you take rapamycin or other drugs cleared by the liver enzyme CYP3A4, be cautious with Schisandra-containing products. Schisandra lignans are well documented to raise blood levels of tacrolimus, which shares that metabolic route with rapamycin.

The reliable takeaways are generic: stable sleep and light cycles, adequate hydration, social contact and stress reduction. These are the variables the stress model manipulated.

Context and Source

  • Open Access Paper: Reversal of Chronic Stress-Induced Inflammaging by Bazi Bushen Formula Through AMPK-Sirtuins Axis Activation and Myeloid Reset
  • Institutions: State Key Laboratory For Innovation and Transformation of Luobing Theory, Hebei Medical University, Shijiazhuang, China; with collaborating authors from Sheba Longevity Center, Sheba Medical Center,Tel Aviv University, Israel, and Renji Hospital, Shanghai Jiao Tong University School of Medicine, China
  • Country: China and Israel
  • Journal Name: Exploration (published by Henan University and John Wiley & Sons Australia, Ltd.)
  • Impact Evaluation: The impact score of this journal is 30.4 (Scopus CiteScore 27.8), evaluated against a typical high-end range of 0–60+ for top general science, therefore this is an Elite impact journal.

Leitura Relacionada:

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This narrative review synthesizes clinical and experimental evidence on how asymmetric dimethylarginine (ADMA),symmetric dimethylarginine (SDMA), interleukin-6 (IL-6), and high-sensitivity C-reactive protein (hsCRP) collectively drive early vascular aging and subclinical atherosclerosis. Rather than acting as redundant markers, these molecules govern two distinct yet mutually reinforcing pathways: the enzymatic uncoupling of nitric oxide production and chronic low-grade vascular inflammation. While elevated ADMA correlates independently with early structural wall thickening and coronary calcification, SDMA primarily reflects systemic vascular stress intertwined with renal filtration capacity.Simultaneously, systemic inflammation mediated by IL-6 and hsCRP degrades functional elasticity and accelerates plaque vulnerability.

Arteries do not all age at the same speed. Two 55-year-olds with identical cholesterol and blood pressure can carry arteries that behave like 45 or 70. Researchers call the fast track “early vascular aging” and the slow track “supernormal” aging. The problem is that standard risk calculators, built on cholesterol, blood pressure, smoking and diabetes, often miss who is on which track. Plenty of people labeled low or intermediate risk already have silent plaque.

This review asks whether a handful of blood tests could close that gap. The candidates fall into two camps.

The first camp concerns nitric oxide, the gas that keeps artery linings relaxed and healthy. ADMA, a molecule left over when cells break down methylated proteins, directly blocks the enzyme that makes nitric oxide. When ADMA builds up, that enzyme can misfire and generate damaging free radicals instead. SDMA, a close chemical cousin, works more indirectly by competing with arginine, the raw material for nitric oxide, at the cell’s entry gates.

The second camp is inflammation. IL-6 is a signaling molecule that activates blood vessel linings and recruits immune cells. It also tells the liver to make CRP, the protein measured by the familiar hsCRP test.

The evidence is uneven. ADMA most often turns up alongside thicker carotid artery walls and more coronary calcium. A pooled analysis of over 6,000 people found a modest link with carotid thickness, strongest in kidney disease. Yet the details wobble. In the Framingham study, ADMA tracked thickening at the carotid fork, where plaques form, but not in the straight segment below it. In a large German population study, ADMA showed no link to either carotid measure at all.

SDMA is cleared almost entirely by the kidneys, so high levels may simply reflect declining kidney function. Still, in the Dallas Heart Study and the German cohort, SDMA stayed linked to coronary calcium and carotid thickness even after accounting for kidney function.

For inflammation, genetics makes the strongest case. People born with variants that dampen IL-6 signaling have fewer heart attacks, which suggests causation rather than coincidence. But in the large US MESA cohort, IL-6 stopped predicting new coronary calcium once standard risk factors and statin use were considered.

hsCRP carries the most practical weight. In the Women’s Health Study, women in the top fifth of hsCRP had about 70 percent higher risk of cardiovascular events over 30 years than those in the bottom fifth. In a Chinese cohort of over 25,000 people, hsCRP above 3 mg/L went with faster arterial stiffening over about four and a half years. A Dutch analysis suggested inflammation may drive stiffening more than wall thickening, though it explained only a sliver of age-related change.

One small Greek trial offers a glimpse of modifiability. Six months of intensive diet and exercise coaching lowered ADMA and improved carotid stiffness and wall thickness in people with mild hypertension, and the more inflammatory the diet, the higher the ADMA.

The authors argue the four markers are complementary rather than interchangeable. That is plausible, but untested. Nobody has yet shown that adding them to a standard risk score changes who gets correctly flagged.

Actionable Insights

The evidence demonstrates that protecting long-term arterial youth requires two practical interventions: maintaining cellular nitric oxide bioavailability and aggressively suppressing systemic inflammation.

First, dietary adjustments produce measurable structural benefits. Clinical trial data cited in the review reveal that adopting an intensive lifestyle intervention consisting of an anti-inflammatory diet and aerobic exercise over six months drove a significant decline in asymmetric dimethylarginine. This biochemical reduction directly correlated with reduced arterial stiffness and decreased carotid wall thickness. For each one-unit decrease in the dietary inflammatory index score,circulating dimethylarginine concentrations declined predictably, verifying that dietary quality directly impacts endothelial enzymatic function.

Second, tracking high-sensitivity C-reactive protein (HS-CRP) provides a functional gauge of arterial stiffness. Prospective cohort data tracking over 25,000 adults indicate that maintaining baseline levels below 1 milligram per liter preserves arterial elasticity. Individuals with concentrations exceeding 3 milligrams per liter experience an additional stiffening rate of more than 40 centimeters per second over four to five years compared to those with low inflammation, an acceleration in mechanical vascular aging equivalent to several additional years of physical deterioration. In women followed for 30 years, the top fifth of hsCRP carried about 1.7 times the event risk of the bottom fifth, a small-to-moderate effect. Retest if a result looks high, since a cold or injury can spike it temporarily.

Third, preserving renal filtration capacity prevents symmetric dimethylarginine accumulation. Maintaining optimal glycemic control, sustaining insulin sensitivity, and engaging in habitual zone-2 aerobic conditioning prevent the lipotoxic and oxidative insults that lock endothelial enzymes into a permanent uncoupled state.

Protect kidney function. Both ADMA and SDMA rise as kidney filtration falls.

Do not expect ADMA, SDMA or IL-6 tests to guide decisions yet. Assays are not standardized, and ADMA explains only about 4 percent of the person-to-person variation in carotid wall thickness.

Context and Source

  • Open Access Paper: Vascular aging biomarkers: the role of ADMA, SDMA, and inflammation, Published 07 October 2026.
  • Authors and Affiliations: Aleksandra Melnitskaia, Liubov Machekhina, Valentina Pykhtina, Alexey Churov, Olga Maltseva, Wu Zhenghi, Olga Tkacheva, and Irina Strazhesko; Russian Gerontological Research and Clinical Center, Moscow, Russia, and Department of Neurology, Shenzhen Institute of Translational Medicine, The First Affiliated Hospital of Shenzhen University / Shenzhen Second People’s Hospital, Shenzhen, China.
  • Journal Name: Frontiers in Cardiovascular Medicine
  • Impact Evaluation: The impact score of this journal is 3.0 (CiteScore 6.1), evaluated against a typical high-end range of 0–60+ for top general science, therefore this is a Medium impact journal.