Intermittent hypoxia-hyperoxia (IHHT)
What is intermittent hypoxia-hyperoxia (ihht)?
Intermittent hypoxia-hyperoxia training (IHHT) means breathing through a mask that alternates a few minutes of low-oxygen air, around 10 to 14% oxygen, with a few minutes of high-oxygen air, around 30 to 40%, while resting. Sessions last about 30 to 45 minutes. It is sold in clinics as cell training, without approval for any medical use.
Listed here because well-known people have tried it on themselves. Trying something is not recommending it; each entry says whether the person tells others to do it.
Who has tried it
Tried by 1 person we can source: 1 kept.
Kept
Bryan JohnsonEntrepreneur, founder of BlueprintBlueprint (Bryan Johnson)
Dates not stated · Does not recommend it to others
Does a 42-minute IHHT session in his morning routine on days when he does not do hyperbaric oxygen therapy.
“Either HBOT (60 or 90 min) or IHHT (42 min)”
Bryan Johnson, Bryan's Protocol (checked November 2026) · Status checked November 1, 2026 · Suggest a correction
What the evidence shows
The trials are small and mostly in older adults with disease. A systematic review of 8 studies found gains in exercise tolerance, peak oxygen uptake and cognition, lower blood sugar and a trend to lower blood pressure, but the studies were too varied to pool [1]. In a pilot study of people with mild cognitive impairment, 15 sessions improved cognitive scores and blood markers linked to Alzheimer disease [2].
Results are not all positive. Adding IHHT to a training program in geriatric patients did not improve mobility or perceived health more than sham air [3], and in metabolic syndrome a course of IHHT did not change a gut-derived heart risk marker overall [4].
No study has tested IHHT in healthy middle-aged people for aging or lifespan, and most trials come from a small group of research centers.
Safety
- IHHT is not approved to treat any condition. Devices are sold for wellness and training.
- Low oxygen can cause dizziness, headache or shortness of breath; sessions are usually run with a pulse oximeter and stopped if oxygen falls too far.
- People with heart disease, uncontrolled high blood pressure, lung disease, anemia, epilepsy or pregnancy should not try it without a physician.
- Long-term effects of repeated sessions in healthy people are unknown.
Common questions
Does Bryan Johnson do IHHT?
Yes. As of November 2026 his morning routine lists either hyperbaric oxygen therapy or a 42-minute IHHT session. His page gives no further detail on the device or results.
Does IHHT work?
How is IHHT different from hyperbaric oxygen?
Hyperbaric oxygen raises oxygen under pressure in a chamber. IHHT keeps normal pressure and switches between low and high oxygen through a mask, aiming to train the body's response to brief oxygen shortage.
Sources
- 1.Behrendt T, Bielitzki R, Behrens M, et al. Effects of Intermittent Hypoxia-Hyperoxia on Performance- and Health-Related Outcomes in Humans: A Systematic Review. Sports Med Open, 2022. doi:10.1186/s40798-022-00450-x
- 2.Serebrovska ZO, Serebrovska TV, Kholin VA, et al. Intermittent Hypoxia-Hyperoxia Training Improves Cognitive Function and Decreases Circulating Biomarkers of Alzheimer's Disease in Patients with Mild Cognitive Impairment: A Pilot Study. Int J Mol Sci, 2019. doi:10.3390/ijms20215405
- 3.Bayer U, Likar R, Pinter G, et al. Effects of intermittent hypoxia-hyperoxia on mobility and perceived health in geriatric patients performing a multimodal training intervention: a randomized controlled trial. BMC Geriatr, 2019. doi:10.1186/s12877-019-1184-1
- 4.Bestavashvili A, Glazachev O, Ibragimova S, et al. Impact of Hypoxia-Hyperoxia Exposures on Cardiometabolic Risk Factors and TMAO Levels in Patients with Metabolic Syndrome. Int J Mol Sci, 2023. doi:10.3390/ijms241914498