Oxygen deprivation kills off brain cells.
Well yes. My rhetorical question was about why the cells die…what mechanisms don’t get energy (when there is no oxygen) to keep working that then result in the death of the cell. These are known. All of that energy need in our BMR assumes oxygen will be available. What does our body do to create a buffer against oxygen shortages or protect against damage from oxygen shortages or quickly repair damage from oxygen shortages? And what besides exercise/ physical activity can build up these defenses, and do such defenses aid in health and longevity beyond the effect of exercise? I think so but I can’t prove it. It’s a bet on resilience.
I don’t know how much of this remains rhetorical. Looking at the HBOT book I have basically there is not that much oxygen storage per se although obviously some is stored in Haemoglobin. Consciousness is lost below a venous pO2 of 19-20mmHg and below 10-12 mmHg you get cardiac collapse.
Although people can train to some extent to manage lower oxygen levels it is not the same as shortage of glucose.
Looking at one chart in the book there are cognitive impacts from lower Oxygen levels at as high as 18% where you get delayed dark adaptation. 15% delays the ability to learn a complex task. Impaired short term memory hits at 13%. Loss of critical judgment arises at 11%. Loss of consciousness occurs around 7%. (table 3.5 page 26). Siesjo 1974.
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adssx
#84
Interesting: altitude is associated with longevity but higher suicide rates:
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The burden of suicide across different altitudes: 11-year geodemographic analysis conducted in 221 cantons in Ecuador ranging from 0 to 4300 m of elevation 2024: “Ecuador is one of the few countries that has a vast range of cantons located at different altitudes. We found that living at higher elevations is positively associated with greater suicide rates. Although the rates are significantly greater as elevation increases, a clear linear relationship is not apparent, likely because of the interplay of socioeconomic factors, including urbanicity. The effect of chronic hypobaric hypoxia on mood cannot be ruled out, although the existence of causal mechanisms remains to be elucidated.”
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Relationships between altitude and depressive symptoms among middle-aged and older adults in China: a longitudinal study from the China health and retirement longitudinal study 2024: “This finding provides evidence of the relationship between altitude and depressive symptoms among middle-aged and older adult community populations in China and shows that depressive symptoms are significantly positively correlated with altitude and other factors, including sex, education level, professional status, and marital status.”
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An examination of the association between altitude and suicide deaths, suicide attempts, and suicidal ideation among veterans at both the patient and geospatial level 2022: “Taken together, our results demonstrate that there is a strong correlation between altitude and suicide rates at all the levels investigated and using different statistical analyses and even after controlling for significant covariates such as percent of age >50yr, percent male, percent white, percent non-Hispanic, median household income, and population density.”
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Suicide and altitude: A systematic review of global literature 2022: “The relationship between altitude and suicide is an evolving science with a small but growing body of literature suggesting altitude is associated with an increased risk of suicide.”
So despite higher suicide rates, all-cause mortality is still lower at high altitudes!
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The initial dark adaptation issues start around 5,000 feet.
I think we understand the life extending mechanism of chronic hypoxia. There are also negative aspects.
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adssx
#86
FYI, in Europe, I found these devices:
For an N=1, I was surprised to see that after taking rapa (12 hours earlier), my resting spo2 was down 5 pts to 94% while sitting in my chair where I do my breath work. I wonder if that has anything to do with why I feel tired after taking rapa…
When I did my breath holds and shallow breathing, everything felt normal (in a bad way) and my spo2 pattern was similar to non-rapa days. After recovery my spo2 went to 99% for a few minutes before gradually falling back to 94% as I rested.
I haven’t been tracking my PI so I’ll start doing that to look for a pattern.
Weird.
adssx
#88
This one is way cheaper (€2,783.00) but I think it doesn’t do hyperoxia: Altitude training workout package for at home | b-Cat High Altitude
It’s the one used in the Dutch Parkinson’s disease study.
I am currently thinking about 17-18% for sleeping in might be a good idea. There do appear to be cognitive issues below that. They are probably not permanent, however.
adssx
#90
There is an interesting question which is what the relationship is between SpO2 and FIO2. It may be that the SpO2 would imply an adequate partial pressure of oxygen when it is actually marginally low.
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adssx
#92
This recent book might have the answer: Hypoxia Conditioning in Health, Exercise and Sport
The Preview PDF offers the first chaper.
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I was thinking of buying it, but realistically on the information we currently have sleeping in 18% O2 at 1 bar is probably good.
We know there are positives at higher altitudes than that, but also negatives.
Where the point of balance is is unclear. However, I am currently sticking to hyperoxia to normoxia simply because that is a lot less hassle.
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I got a quote for a hypoxic only generator and it was ~$1k with shipping. I imagine the hypoxic/hyperoxic combo is probably similar.
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adssx
#95
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adssx
#96
Just published in Science Translation Medicine: Hypoxia as a medicine
They focus on chronic hypoxia (“at least 3 days at an oxygen concentration less than 21% at sea level with no more than minimal interruption”) as opposed to hypoxic preconditioning, remote ischemic preconditioning, acute intermittent hypoxia, and hyperbaric hyperoxia. I like that part:
With 14 million people worldwide permanently inhabiting elevations above 3500 m (16) (equivalent to 13.6% oxygen at sea level), there are multiple locations to which a patient might move to access “natural” CCH. Permanent settlements above 3500 m are found in Argentina, Bhutan, Bolivia, Chile, China, India, Kyrgyzstan, Nepal, Peru, and Tajikistan. Although many of these high-altitude settlements are small villages in which medical infrastructure to care for patients with complex disease might need to be built, the list includes major cities as well. El Alto, Peru (elevation of 4150 m, equivalent to 12.5% oxygen at sea level) has a population of approximately 1 million people, suggesting that it could host patients without overwhelming local infrastructure.
adssx
#98
This statement cites this low quality paper: Mechanism, prevention and treatment of cognitive impairment caused by high altitude exposure 2023
They define high altitude as > 2,500 m. They note:
Minimal impairments have been noted at moderate altitudes of 2000–3,000 m, noticeable psychomotor impairments have been seen at 3,000–4,000 m, above 5,000 m, spatial memory was significantly impaired, and impairments in encoding and short-term memory were particularly evident at extremely HAs over 6,000 m
The equivalent normobaric FiO2 of these altitudes are:
- 2,000 m ~ 16%
- 2,500 m ~ 15%
- 3,000 m ~ 14%
- 4,000 m ~ 12%
- 5,000 m ~ 11%
- 6,000 m ~ 9%
Here are the protocols recommended by one hypoxia machine provider:
The main difference between the hyperoxic and normoxic protocols is that the post-hypoxic phase goes from 5 min (normoxia at 21%) to 3 min (hyperoxia at about 34%). This is in line with Intermittent Hypoxia/Hyperoxia Versus Intermittent Hypoxia/Normoxia: Comparative Study in Prediabetes 2019 that found that in these conditions the outcomes of IHT and IHHT were equivalent: “One of the advantages of IHHT over IHT observed in this study could be some reduction in the duration of the sessions due to shortening reoxygenation periods.”
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When you use hyperoxia the post-hypoxic phase includes normoxia in normobaric conditions and that can be hours.
My own view is that HIF 1 alpha needs some time to function possibly hours rather than minutes.
adssx
#100
Here they tried to evaluate the optimal protocol for cognition: Neuroprotective Effects of Moderate Hypoxia: A Systematic Review 2023
Taken together, this suggests that the optimal intensity and dosing of hypoxia for exploiting neuroplastic benefits are likely to be moderate around 10–16% O2 with shorter intermittent or continuous types of exposures involving 30 min to 4 h sessions, with repeated frequency +3 days weekly over 2–6 weeks.
Based on that, the same authors are conducting this trial: Effects of cognitive training under hypoxia on cognitive proficiency and neuroplasticity in remitted patients with mood disorders and healthy individuals: ALTIBRAIN study protocol for a randomized controlled trial 2024
During the three-week treatment, participants breathe 12% ambient oxygen (≈ 4400 m altitude) or approximately normal sea-level oxygen (20%) in a treatment room, 3.5 h daily, six days per week (18 sessions in total).
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