At its most fundamental, oxygen is crucial for life. So an enhanced oxygen delivery would be beneficial. Michael Jackson, oddly enough, popularized the treatment in the 1980s when he would sleep in an oxygen chamber. If you are asthmatic and show up at A&E, within seconds you are put on high-concentration oxygen. If you look at your left shoulder, then your right and then back at your phone, you realize that both your shoulders are leaning forward and your head tilted forward: your lung capacity has decreased by 30%. Some maintain that position through the day. So a process to oxygenate the blood efficiently can have its benefits.
Hyperbaric therapy takes this process a step further by introducing 100% oxygen within a pressure chamber. This has the advantage of increasing the delivery manifold. If you know a snorer or someone who suffers from COPD (chronic obstructive pulmonary disease), they most likely will have a cpap device. The device delivers normal air under pressure through a gel mask. Try it. Suddenly your chest opens out and you feel more refreshed. In a similar manner a hyperbaric chamber delivers oxygen under pressure.
The further effect of hyperbaric therapy is controlled oxidative stress. This is the creation of reactive oxygen species which speed up wound healing. So the primary advantage of the therapy is in diabetic foot ulcers and post cancer treatments.
The therapy is well-established as a medical treatment and has a strong safety profile. That said it does need to be administered by qualified professionals to minimize side-effects that stem from being under pressure and receiving 100% oxygen.
For the average person? It’s possibly worth a try. Though a 2016 study indicated no enhanced recovery in athletes biomarkers post-training.