HBOT increases telomere length and reduces immunosenescence in blood cells

Study Design

Type & Setting
Design: Prospective, single-arm pre-post interventional study
Location: Shamir (Assaf-Harofeh) Medical Center / Sagol Center for Hyperbaric Medicine and Research, Israel
Publication: Aging (Albany NY), Nov 18, 2020; 12(22):22445–22456; DOI 10.18632/aging.202188; PMID 33206062. PubMed

Participants & Timepoints
Included: 35 independently living adults ≥ 64 y.
Analyzed: 30 completed HBOT; telomere analysis n = 25, senescence n = 20 (quality/cell count).
Blood draws: Baseline, session 30, session 60, 10–14 days post HBOT. Aging-US

HBOT Protocol (constant)
60 sessions over ~3 months (5×/week), 2 ATA, 100% O₂, 90 min, 3× 5-min air breaks; multiplace chamber (Starmed-2700, HAUX). No lifestyle/medication changes allowed. Aging-US

Methods (short & clear)

Telomere length (RTL): Flow-FISH (Dako PNA/FITC kit), subsets: CD3⁺/CD4⁺, CD3⁺/CD8⁺, CD3⁺/CD56⁺, CD19⁺. Results reported as relative telomere length vs. reference cell line TCL-1301. Aging-US

Immune senescence: CD28-negative helper T cells (CD3⁺CD4⁺CD28⁻) and cytotoxic T cells (CD3⁺CD8⁺CD28⁻) via flow cytometry (Miltenyi). CD57 was not available as a confirmatory marker. Aging-US

HIF-1α: Intracellular staining to confirm the hyperoxic-hypoxic response. Aging-US

Results

Telomere length (relative change vs. baseline):

• B cells: +25.7% (S30; p=0.007), +29.4% (S60; p=0.0001), +37.6% (post; p=0.007); within-group significant (RM-ANOVA p=0.017).

• T-helper cells: +21.7% (S30; p=0.042), +23.7% (S60; p=0.012), +29.3% (post; p=0.005); RM-ANOVA trend (p≈0.06).

• Cytotoxic T cells: +24.1% (S60; p=0.0019), +19.6% (post; p=0.023).

• NK cells: +20.6% (S60; p=0.013); post +22.2% (p=0.06).

Immune senescence (CD28-null fraction):

• Helper T cells: −37.3% (post; p<0.0001); S30 −19.7% (p=0.09), S60 −11.7% (p=0.20); RM-ANOVA p=0.01.

• Cytotoxic T cells: −12.2% (S30; p<0.0001), −9.8% (S60; p=0.002), −11.0% (post; p=0.0004); RM-ANOVA p=0.018.

Biological plausibility: HIF-1α increased significantly until session 60 (10.5 → 19.7; p=0.006) and partially normalized 2 weeks post HBOT—consistent with hormetic adaptation to repeated hyperoxia. Aging-US

Interpretation (simple)

• Telomere extension >20% in multiple lymphocyte subsets is unusually strong compared to lifestyle interventions (typically 0–5% in exercise/diet studies) – HBOT clearly stands out.

• Senolytic effect: The decline in CD28-negative T cells suggests fewer aging/“exhausted” immune cells—potentially relevant for infection defense and inflammation balance in aging.

• Time course: Many effects appeared as early as session 30 and persisted 1–2 weeks post HBOT (notably B-cell telomeres and helper T-cell senescence). Aging-US

Limitations (transparent)

• No control arm (single-arm) and modest sample size (dropouts/quality reduced n).

• Only blood leukocytes analyzed (no organ systems).

• CD57 not available (to confirm senescence marker).

• Long-term persistence of effects unclear (follow-up 10–14 days). Aging-US

Practical implications

• Healthy aging: HBOT could improve immune fitness and cellular resilience.

• Protocol design: Effects often peaked around session 30 – future studies may optimize dose/time curves.

• Monitoring: Flow-FISH and immunophenotyping offer measurable biomarkers for personalization. Aging-US

What do “longer telomeres” mean in practice?

Longer telomeres indicate greater replicative capacity and less “biological wear and tear”; they are associated with more favorable aging outcomes. (Background in full text/introduction) Aging-US

Is HBOT therefore an anti-aging therapy?

The data are promising but not conclusive: No control arm and limited follow-up. Randomized studies are needed to clarify how strong and durable the effects really are. Aging-US