Here’s What a Post-Workout Sauna Session Can Do For Your Fitness Goals

It may not be the number one thing you want to think about in the middle of a summer heatwave, but let’s talk saunas — and specifically, whether saunas have any significant post-workout benefits. Maybe you’ve seen people heading into your gym’s sauna after a workout but never really understood why, or maybe you just want to know why people would want to follow up a sweat session with . . . another sweat session. You’ve come to the right place, but first, let’s cover some background info.

There are a few different kinds of saunas, but the main ones you hear about are the traditional sauna, which heats up the air and increases humidity to produce sweat, and the infrared sauna, which heats your skin directly (without as much ambient temperature change) by using infrared lamps that generate electromagnetic radiation. Since the infrared sauna is more targeted, the temperature in infrared saunas is significantly lower than that of traditional saunas. They range from 120 to 140˚F, whereas traditional saunas are more like 150 to 180˚F. Both types come with post-workout benefits, but keep in mind that infrared saunas are newer and not as well-researched as traditional saunas.

Should you use a sauna — whether infrared or traditional — after your next workout? And what should you know before going into the (very sweaty) experience? (Hint: hydration will be key.) POPSUGAR spoke to two experts to get the scoop on sweating safely in a post-workout sauna sesh.

Sauna Benefits After a Workout

Using a sauna after a workout can be beneficial, but it’s not as straightforward as you’d think. According to experts and research, post-workout sauna use can:

• Improve heat tolerance: Research shows that using a traditional sauna can improve your body’s reaction to heat, which can be beneficial if you often work out in hot conditions. “When you head into the sauna, your body will respond as expected by sending blood to your skin to help you sweat and avoid overheating,” explains exercise physiologist Stacy Sims, PhD. Your body’s blood flow will already be slightly limited due to dehydration from your workout, so combining that with the increased temperature in a sauna creates “a strong survival stimulus to improve your body’s ability to handle the heat,” Dr. Sims says. With consistent post-workout sauna use, she says, your body will be pushed to start sweating earlier. That’s a good thing for athletes because sweating helps you maintain optimal body temperature and function when it’s hot out.
• Boost workout performance: Post-exercise traditional sauna use can also improve workout performance overall, likely because saunas help increase blood flow, a 2007 study notes. Sauna use helps to “increase both red cells, which increases your body’s ability to carry and deliver oxygen to working muscles, and plasma volume, which boosts your blood volume and subsequent performance,” Dr. Sims says. ACE-certified personal trainer Stephanie Thomas adds, “When used a few times a week post-workout, [saunas] can help you improve your endurance and simply feel stronger during your workouts.” A 2015 study notes that using an infrared sauna with a mild temperature (95 to 122°F) and light humidity (25 to 35 percent) “appears favorable for the neuromuscular system” and can help athletes recover from maximal endurance performance.
• Relieve joint pain and muscle soreness: Since the heat of a traditional sauna will relax and dilate your blood vessels, it may help loosen up stiff muscles and joints after a workout. For infrared saunas, a 2009 study showed that sauna sessions improved pain, stiffness, and fatigue for people with chronic musculoskeletal diseases, including rheumatoid arthritis.
• Relax your mind and body: Yes, it’s sweaty and hot in there, but saunas are also designed to be very relaxing — which is a major reason people love them. For example, a 2019 survey of 482 people from the US, Finland, and Australia found that using a sauna five to 15 times per month was associated with high “mental well-being.” A 2018 review, meanwhile, notes that using the sauna causes your body to release endorphins and other feel-good chemicals, as well as results in a state of “forced mindfulness” and relaxation that can lead to real psychological benefits — all especially pleasant additions to your post-workout routine. Using a sauna is “an amazing way to relax your body and mind after a tough workout session,” Thomas confirms.

While there’s plenty of research supporting post-workout sauna use for improved performance and heat tolerance, a 2019 study showed that those effects might not always hold true. The small study found that, in a group of 20 swimmers, athletes who used a sauna directly after a training session performed “significantly worse” in performance tests the next day.

While saunas do relax your body and mind, they also put your body under a certain amount of stress — otherwise, it would have no reason to adapt and improve its athletic performance and heat tolerance. That stress, as the 2019 study shows, can cause some less-than-desirable effects as your body adjusts. As the study authors note, “coaches and athletes should be careful with postexercise [sauna use] if high-intensity training and/or competitions are scheduled on the following day.”

So, Should You Try a Post-Workout Sauna?

Many people enjoy using a sauna after a workout, and there are some solid potential benefits, including improved heat tolerance and training performance. That said, it’s possible to experience next-day performance drawbacks in training or competitions — so, to be safe, don’t hit the sauna the day before a race or PR attempt. But if you are dealing with muscle soreness, often exercise in heat, or are looking for better workout performance over time, a post-workout sauna session might be worth a shot.

Getting the Most Out of Your Post-Workout Sauna Session

If you do choose to use a sauna for post-workout recovery, our experts have a few safety guidelines to keep in mind.

For one, if you’re new to sauna bathing, definitely don’t jump in with a 30-minute session — it will not be a pleasant experience. “Initially stay in for five to 10 minutes,” Dr. Sims says. General time guidelines vary, with some sources noting that five- to 20-minute sauna sessions are perfectly fine for reaping the health benefits; Dr. Sims says you can ultimately aim for 25- to 30-minute sauna sessions where the temperature doesn’t exceed 165˚F. It’s best to build up to that slowly and experiment with what time frame works best for you — but it’s not advised to exceed that 30-minute threshold. “As you build up, it is OK to step out of the sauna for a minute or two and then head back in,” Dr. Sims adds. Try to start your sauna session within a few hours after the end of your workout, and aim for three to five sessions a week once you’ve built up to this more consistent use over time.

Another must: hydrating before and after sauna use. “It is advised to slowly rehydrate over the course of two to three hours, postsauna, with cool beverages,” Dr. Sims says. She doesn’t recommend drinking water during your sauna session, as this could be ultimately counterproductive — your body has to be stressed to some degree to produce those heat-tolerance and performance adaptations — but it’s important to listen to your body and take a break or get a drink of water when you need to. (More on that below.) Most sauna brands, infrared and traditional, also recommend drinking water (some recommend up to 32 ounces) before starting your post-workout sauna session, to avoid extreme dehydration.

When your sauna session is over, drape a cool, damp towel over your back to slowly bring your body temperature back down, Dr. Sims says. She advises against “packing yourself in ice,” though, because “ice on the skin is too cold and actually constricts your blood vessels,” which you just opened up by sitting in heat.

Sauna Safety and Who Shouldn’t Use a Sauna

It’s also worth noting that whenever you hit the sauna (after a workout or otherwise), there are some general safety risks to be aware of. For one thing, sauna use can cause overheating and dehydration, so make sure to step out of the sauna, sit down, and drink some water if you start experiencing symptoms (such as mouth dryness, extreme thirst, headaches, and dizziness or lightheadedness).

Consult your doctor before using a sauna if you have a heart condition or are on medication, as sauna use can interfere with some medications (and certain medications actually increase your risk of heat exhaustion). Also, don’t use a sauna (especially a public sauna) if you have a cold, the flu, or COVID-19. Do not drink alcohol before, during, or after using a sauna, as the sauna-induced dehydration will increase the effects of alcohol and can increase your risk of low blood pressure, research says. (For those reasons, you shouldn’t use a sauna when you’re hungover, either.) Finally, avoid using a sauna when you’re pregnant, too.

Post-workout sauna bathing can be a relaxing experience, but make sure you take the right precautions going in: hydrate, don’t push past your limits, and talk to your doctor first to make sure sauna use is safe for you. After that? Fire up the sauna, grab your plushest towel and comfiest slides, and get ready to sweat out the soreness.