Infrared saunas like the Spartan-approved Clearlight Infrared Sauna — which Spartan CEO Joe De Sena uses as part of his regular training routine — have been popping up everywhere, from elite training facilities and boutique studios to at-home garage gyms. And it's for a good reason: There are signs that this type of heat treatment can seriously elevate your athletic game, from running a Trail race to competing in a Spartan race in some intense temperatures (like Abu Dhabi) and gaining multiple pounds of muscle. 

Related: 5 Ways to Put on 10 Pounds of Lean Muscle FAST

Here are three reasons why Spartan coaches have infrared sauna sessions worked into their personal training plans.

The Benefits of Sauna Use for Athletes

1. It Could Help You Run Like Hell

When you get hot, you sweat. When you sweat, you get dehydrated. And when you get dehydrated, it gets harder for your blood to pump. According to exercise physiologist Stacy T. Sims, Ph.D., an adjunct researcher at Stanford University’s Prevention Research Center, this decreases oxygen tension in the kidneys, triggering the release of EPO (a peptide hormone), which, in turn, stimulates red blood cell production and increases blood volume.

Both of these things could lead to better aerobic capacity. Case in point: A study on male long-distance runners showed that using the sauna after a workout for three weeks increased the athletes time to exhaustion — or their running endurance — by 32% when compared to not using the sauna. 

Related: 10 Tips to Maximize Sauna Training Benefits and Spike Race Performance

Spartan Master Coach and competitive athlete Trevor Franklin uses the infrared sauna multiple times per week for 20 minutes per day.

“There’s a lot of performance benefits when you sweat like that, so I use it regularly,” he says.

2. It Could Prepare You for Hot Situations

If you're planning to compete in a Spartan race during the summer or in a hot location, a regular infrared sauna session is a worthy training ritual to consider. Here’s why: A 2021 study published in the European Journal of Applied Physiology found that trained athletes using a sauna for three weeks had developed better tolerance to heat and saw an improvement in exercise performance. In other words, the heat will suck less when you subject yourself to it beforehand.

3. It Could Help Support Muscle Recovery

When you hop in a sauna, your body starts to release heat shock proteins (HSPs). These proteins are produced by the body when it’s exposed to stressful conditions (like a 140-degree sauna), and according to research, sauna use can increase HSPs by nearly 50%.

Related: 3 Ways That Infrared Saunas Can Help You Crush Your Next Race

That’s a significant bump, especially in something that experts suggest to help maintain muscle integrity and facilitate muscle regeneration and recovery. 

“Saunas can speed up the recovery process when you feel sore from a big workout or intense training session,” Spartan Master Coach and triathlete Kristina Centenari says. “If I have access to one, I’m using it twice per week for about 20 to 40 minutes.”