HBOT and ageing: what the telomere study found, and what it didn't

What the researchers did

The study ran at a hospital in Israel¹. Everyone in it was 64 or older, lived independently and had no heart or stroke problems in the past year.

Each person had 60 sessions over about three months, five days a week. A session was 90 minutes at 2.0 ATA, about twice the pressure of the air around us, breathing 100% oxygen through a mask. Every 20 minutes they took a five-minute break on normal air.

Blood was taken before the first session, at the 30th, at the 60th, and one to two weeks after the last. In the white blood cells, the team measured two things¹:

• Telomeres, the protective caps on the ends of our chromosomes. They get shorter as we age, which is why they're studied as a marker of ageing.
• Senescent T cells, immune cells that have stopped dividing. Their share tends to grow as we get older.

What they found

Thirty people finished all 60 sessions. By the last session, telomeres were 21 to 29% longer than at the start in all four kinds of white blood cell the team looked at¹. One to two weeks after the sessions ended, the biggest change was in B cells, at 38% longer.

One to two weeks after the last session, the share of senescent T helper cells was 37% lower than at the start, and senescent T cytotoxic cells 11% lower¹. The authors suggest hyperbaric oxygen may act on these markers of cell ageing.

What it didn't test

The authors list most of these limits themselves¹:

• No comparison group. Everyone had the sessions, so we can't tell how much would have changed anyway.
• A small group. 35 people started, 30 finished, and the telomere results come from 25 of them.
• Blood cells only. It didn't look at health, how people felt, or how long they live.
• No long-term follow-up. Nobody knows how long the change lasted.
• Hospital-strength sessions. 2.0 ATA with 100% oxygen by mask, 60 times.

Three of the authors work for a company that offers HBOT programmes, and one owns shares in it. The paper says so in its declarations.

A trial with a comparison group

The same team ran a randomised trial in 63 healthy adults over 64, with the same 60-session plan². About half had the sessions; the rest carried on as normal. After three months, the group who had the sessions improved more on computer-based thinking tests, mostly in attention and how quickly they processed information.

That trial measured thinking, not telomeres. The comparison group had no sessions at all rather than a pretend one, and everyone knew which group they were in, though the people running the tests didn't².

How this compares with a session at Sorted

Our chambers are mild, soft-shell chambers. Sessions run at 1.2 to 1.5 ATA, and you breathe a higher concentration of oxygen while you rest. Both studies used 2.0 ATA in a hospital chamber, with 100% oxygen by mask, 60 times over three months.

So these studies can't tell us whether milder sessions do the same, and we don't claim they do.