A-listers are lying in locked, pressurized chambers to achieve peak wellness. I tried hyperbaric oxygen therapy for myself, and here's what it was like.

I was invited to check out The Body Lab in a journalist capacity shortly after it opened in January 2022, and I tried out some of the treatments, including hyperbaric oxygen therapy.

Before visiting The Body Lab, I didn't know much about hyperbaric oxygen therapy, other than it might have anti-aging benefits and was popular among celebrities.

Hyperbaric oxygen therapy is done in a compression chamber and is often used by pilots, astronauts, and deep-sea divers.

A-listers such as Cristiano Ronaldo, Michael Phelps, LeBron James, Mohamed Salah, and Justin Bieber all reportedly use the treatment for various ailments.

The Body Lab claims its Hyperbaric Hydroxy AirPod speeds up the body's healing process by increasing oxygen absorption by up to 35%.

Although there hasn't been a huge amount of research yet on this kind of therapy, a small study by Tel Aviv University found that it could reduce some biological signs of aging, as Insider's Gabby Landsverk reported.

The Body Lab encourages its clients to have the therapy for a range of supposed health benefits, including increased energy and stamina, optimized cellular health, better wound healing, improved cognitive function, and pain relief.

Being in the hyperbaric chamber was slightly scary, but I did come out feeling both relaxed and energized.

The Body Lab, where I tried hyperbaric therapy for the first time, is described as a place "where science and technology meets the luxury of five-star fitness and wellness," and membership costs £4,950 ($6,800) to £16,000 ($21,800) a year.

It offers a gym and cutting-edge treatments including hyperbaric oxygen therapy, cryotherapy, and a float tank.

The top-tier memberships include unlimited use of the facilities (including personal-training sessions), one nutritional consultation per month, and a quarterly biomarker analysis.

After climbing (rather ungracefully) into the chamber and lying down, Nick Jacobs, The Body Lab's head of sales, locked me in and stayed with me for three minutes as oxygen was slowly pumped in to increase the air pressure three times more than normal.

There was a pillow and a bolster, and I felt quite comfortable.

Above my head, a panel displayed the air pressure and remaining time in the chamber. I could also see the tube pumping out oxygen.

Jacobs said that some of the elite athletes who use the chamber, like rugby players, have to bend their legs to fit into it.

I didn't feel as claustrophobic as I expected, thanks to the clear roof, but it was mildly scary knowing I couldn't let myself out and just had to trust that Jacobs would come and release me.

He came back to check on me a few times during the 45 minutes and was able to speak to me on a special phone each time.

I had my cell phone inside with me, so I could also text him if I needed to.

I took my laptop and phone (and some water) inside with me and attempted a bit of work, but it was quite hard while lying down.

Jacobs encouraged me to relax into it and rest, and I did start to feel sleepy. The air pumping in created a subtle whirring sound, almost like white noise.

Of course, lying down anywhere for 45 minutes mid-morning on a weekday would probably make me feel good.

Lowering the pressure took a few minutes, and reminded me of being on a plane.

I felt slightly light-headed when I came out but energized, too.

Jacobs told me some people step out and immediately feel like they've had 10 coffees. Other people feel a more subtle, sustained level of energy.

It's hard to say how much of an effect the hyperbaric chamber had on me, but I certainly did feel good and slept very well that night.