Longevity Briefs: Can Hyperbaric Oxygen Therapy Improve Fitness In Old Age?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

Hyperbaric oxygen therapy, or HBOT, is a treatment during which people breathe 100% oxygen in a high pressure (hyperbaric) environment. This significantly raises the amount of oxygen that is dissolved in the blood plasma (the liquid, non-cellular part of the blood), thereby increasing the delivery of oxygen to tissues, even those that are inaccessible to red blood cells due to damaged blood vessels. There’s some indication that this might have anti-ageing benefits. For example, one study found that 60 days of HBOT was associated with increased telomere length. In a recent study, researchers have investigated the effects of HBOT on cardiorespiratory fitness in older people.

The discovery:

In the study, researchers randomised 63 participants with a median age of 70 to receive either 60 sessions of 90 minutes HBOT at 200% atmospheric pressure over 12 weeks, or no intervention. Participants were also asked not to change anything about their current lifestyle. They found that, at the end of the intervention, participants who received HBOT had significantly higher myocardial blood flow and volume (respectively, the volume of blood supplied to the heart muscle and the volume of blood present within the heart muscle at a given time). They also measured significant increases in two important fitness metrics: VO2max and VO2VT1 oxygen consumption.

VO2max is essentially the maximum rate at which the body consumes oxygen during exercise. It is a measure of overall physical fitness because it depends on how quickly the lungs can exchange oxygen with the blood, how quickly the circulatory system can deliver that oxygen to the muscles, and how quickly the muscles can utilise that oxygen. Higher VO2max correlates well with reduced mortality in older age. VO2VT1 oxygen consumption is the rate of oxygen consumption at the moment the body starts to use some anaerobic energy production to complement aerobic activity. Practically speaking, people with higher values can maintain moderate intensity exercise for longer.

The implications:

So, this study suggests that HBOT may lead to significant improvements in physical fitness among generally healthy elderly people. Brief exposure to high levels of oxygen can, paradoxically, stimulate some of the same adaptive changes as low oxygen levels during exercise, leading to improved blood vessel health. This might explain the beneficial effects on heart muscle blood supply. HBOT also appears to improve the function of the mitochondria, the power plants of the cell, leading to improved aerobic health.

While this trial was randomised, the control group was assigned to no treatment, rather than a fake HBOT treatment (which would have been very difficult to pull off). As such, there is a large potential for a placebo effect – HBOT is a very involved process in which you are monitored by people in white coats and inevitably made to feel quite special. The researchers attempted to monitor participants to ensure they did not make any lifestyle changes during the intervention, but realistically, they would not have known if participants in the HBOT group started pushing themselves a little harder during their afternoon walk. One also has to wonder if the 7 and a half hours of HBOT per week (plus travel time) couldn’t have been better spent on regular exercise, which we know has the same benefits as demonstrated here and more besides. Still, not everyone in their 70s has the ability to exercise effectively and safely, and HBOT might bring additional value when combined with exercise.