The Telomere Study: What It Found
In 35 healthy adults over age 64, 60 HBOT sessions increased telomere length by more than 20% across all immune cell types and reduced senescent cells by up to 37%. Those 2020 findings from the Sagol Center sparked widespread interest in HBOT as an anti-aging intervention. The research has expanded since then, but most of it still comes from a single group in Tel Aviv.
The study enrolled 35 healthy adults aged 64 and older. Participants underwent 60 daily HBOT sessions at 2.0 ATA with intermittent air breaks. Telomere length and senescent cell populations in peripheral blood mononuclear cells were measured at baseline, after 30 sessions, after 60 sessions, and 1-2 weeks post-treatment.
Key Results: Telomere Length
| Cell Type | Change at 60 Sessions | p-value |
|---|---|---|
| B cells | +29.39% | p = 0.0001 |
| T helper cells (CD4+) | +23.69% | p = 0.012 |
| T cytotoxic cells (CD8+) | +24.13% | p = 0.0019 |
| Senescent T helper cells | -37.30% | p < 0.0001 |
| Senescent T cytotoxic cells | -10.96% | p = 0.0004 |
“In 35 healthy adults over age 64, 60 HBOT sessions increased telomere length by more than 20% across all immune cell types and reduced senescent T helper cells by 37% — the largest telomere elongation documented from any single intervention in humans.”
Hachmo et al., Aging, 2020 (no control group; findings not independently replicated as of 2026)
Important Caveats
Before drawing conclusions, several limitations of the 2020 telomere study must be understood:
- No sham control: This was a prospective trial without randomization or a control group. Participants knew they were receiving HBOT. Placebo effects cannot be ruled out for subjective outcomes, though the telomere measurements are objective blood assays.
- Small sample: n=35 for telomere data. High standard deviations (SD 23-53% for some measurements) indicate large inter-individual variability. Some individuals may have seen much less change, or none at all.
- Single research group: As of 2026, no independent group has replicated the specific telomere lengthening findings. The Maroon 2022 case report (one subject, the author himself) described telomere doubling but is not scientific replication.
- Immune cells only: Telomere changes were measured in peripheral blood immune cells. Whether similar changes occur in other tissues is unknown.
- Long-term durability unknown: The study did not follow participants beyond a few weeks post-treatment. Whether telomere changes persist is unknown.
Why Telomeres Matter for Aging
Telomeres are protective caps at the ends of chromosomes that shorten with each cell division. Shortened telomeres are associated with cellular senescence, reduced immune function, and increased disease risk. Telomere length is considered a reliable biomarker of biological age.
Before the Hachmo 2020 study, interventions such as exercise, meditation, and dietary changes had shown modest slowing of telomere shortening, but none had demonstrated active lengthening of the magnitude reported with HBOT. The study also found simultaneous reductions in senescent cells, which release inflammatory cytokines (SASP) that damage surrounding tissue.
The Physical Performance RCT: Stronger Evidence
While the telomere findings lack a control group, a 2024 randomized controlled trial by Hadanny and colleagues provides more rigorous evidence for HBOT’s effects on aging.4
The study enrolled 63 adults over age 64, randomized to either 60 daily HBOT sessions or a control group. Results:
- VO2Max/kg: +1.91 ml/kg/min, effect size 0.455 (p=0.003)
- VO2 at first ventilatory threshold: +160 ml/min (p<0.001), effect size 0.617
- Cardiac blood flow: effect size 0.797 (p=0.008)
- Cardiac blood volume: effect size 0.896 (p=0.009)
“A randomized controlled trial found that 60 HBOT sessions at 2.0 ATA significantly improved VO2Max (p=0.003) and cardiac blood flow (effect size 0.80) in adults over 64, providing controlled evidence that HBOT improves physical capacity in aging adults.”
Hadanny et al., BMC Geriatrics, 2024
The Mechanism: Hyperoxic-Hypoxic Paradox
Kamat, Mendelsohn, and Larrick (2021) described the mechanism in a review published in Rejuvenation Research.6 During HBOT, tissues experience dramatically elevated oxygen. When the session ends and the patient returns to normal pressure, tissues experience a relative drop in oxygen, a signal that mimics hypoxia at the cellular level. This intermittent cycling triggers HIF-1alpha activation (normally a hypoxia signal) and SIRT1 induction (a longevity-associated gene). The key insight is that SIRT1 is induced by hyperoxia but reduced by chronic hypoxia, making HBOT unique in combining both pathways.
Skin Aging Evidence
A companion 2021 study from the same research group examined skin biopsies from 13 participants before and after HBOT.2 Results showed significant increases in collagen density (p<0.001, effect size 1.10), elastic fiber length (p<0.0001, effect size 2.71), and blood vessel formation (p=0.02, effect size 1.00), along with significant decreases in fiber fragmentation and tissue senescent cells. This was the first human study to show HBOT can modulate skin aging at the tissue level. Sample size was n=13 with no control group.
What Does the HBOT Protocol Look Like?
- Pressure: 2.0 ATA (hard chamber only)
- Oxygen: 100% medical-grade oxygen via mask
- Session structure: 90 minutes total, three 20-minute oxygen periods with 5-minute air breaks
- Frequency: 5 sessions per week
- Duration: 60 sessions over 12 weeks
- Cost: Approximately $12,000-$24,000 at clinical facilities
Comparison with Other Longevity Interventions
| Intervention | Telomere Effect | Senolytic Effect | Evidence Level |
|---|---|---|---|
| HBOT (Hachmo 2020 protocol) | >20% lengthening (no control) | -11 to -37% (no control) | 1 uncontrolled prospective study (n=35), not replicated |
| Exercise | Slows shortening | Modest effect | Multiple large observational studies |
| Dasatinib + Quercetin | None demonstrated | Significant clearance | Phase II human trials |
| NAD+ supplementation | None demonstrated | Indirect | Animal + early human data |
For a broader look at the anti-aging evidence, see our guide on hyperbaric chamber anti-aging protocols and HBOT for longevity and performance.
- Hachmo Y, Hadanny A, Abu Hamed R, et al. Hyperbaric oxygen therapy increases telomere length and decreases immunosenescence in isolated blood cells: a prospective trial. Aging. 2020;12(22):22445-22456. DOI: 10.18632/aging.202188. PMID: 33206062.
- Hachmo Y, Hadanny A, Mendelovic S, et al. The effect of hyperbaric oxygen therapy on the pathophysiology of skin aging: a prospective clinical trial. Aging. 2021;13(22):24500-24510. DOI: 10.18632/aging.203701. PMID: 34784294.
- Hadanny A, Forer R, Volodarsky D, et al. Hyperbaric oxygen therapy induces transcriptome changes in elderly. Aging. 2021;13(23):25090-25099. DOI: 10.18632/aging.203709. PMID: 34818212.
- Hadanny A, Sasson E, Copel L, et al. Physical enhancement of older adults using hyperbaric oxygen: a randomized controlled trial. BMC Geriatrics. 2024;24:537. DOI: 10.1186/s12877-024-05146-3. PMID: 38961397.
- Fu Q, Duan R, Sun Y, Li Q. Hyperbaric oxygen therapy for healthy aging: From mechanisms to therapeutics. Redox Biol. 2022;53:102352. DOI: 10.1016/j.redox.2022.102352. PMID: 35649312.
- Kamat S, Mendelsohn A, Larrick J. Rejuvenation Through Oxygen, More or Less. Rejuvenation Res. 2021;24(2):158-163. DOI: 10.1089/rej.2021.0014. PMID: 33784834.
- Maroon J. The effect of hyperbaric oxygen therapy on cognition, performance, proteomics, and telomere length. Front Neurol. 2022;13:949536. DOI: 10.3389/fneur.2022.949536. PMID: 35968296.
- Tessema B, et al. Effects of Hyperoxia on Aging Biomarkers: A Systematic Review. Front Aging. 2022;2:783144. DOI: 10.3389/fragi.2021.783144. PMID: 35822043.
Medical Disclaimer
The content on BaricBoost.com is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
Author
Seph Fontane Pennock is the founder of BaricBoost.com and Regenerated.com, a clinic directory for regenerative medicine serving 10,000+ providers across the United States. He previously built and sold PositivePsychology.com, which grew to 19 million users and became the largest evidence-based positive psychology resource on the web. Seph brings direct experience as an HBOT patient, having completed protocols at clinics across three continents while navigating mold illness, systemic inflammation, and autoimmune conditions. His treatment journey includes hyperbaric oxygen therapy, peptide protocols, NAD+ therapy, and consultations with specialists from Dubai to Cape Town to Mexico. This combination of entrepreneurial track record and lived patient experience shapes everything published on BaricBoost.com. Every article is grounded in peer-reviewed research, informed by real clinical encounters, and written for patients making high-stakes treatment decisions. Seph's focus is on bringing transparency, scientific rigor, and practical guidance to the hyperbaric oxygen therapy space.
