Cryotherapy. Acupuncture. Hypnosis. When it comes to wellness splurges, it seems like there's a new "must do" for your health every week. But what's that saying? What's old is new again. This time around, everyone from naturopaths and yogis to stressed execs and functional fitness fans are talking about something that's been around for a long time: saunas.

The tradition has been a central part of various cultures and societies for centuries. "But they’re becoming especially hot because they’re more accessible than ever before,” says New York City-based psychotherapist Paul Hokemeyer, Ph.D.

Nope, no longer do you need a sauna in your gym to get your sweat on: Now, sauna studios including Sweattheory in Los Angeles and HigherDOSE in New York City let people heat up for roughly a dollar a minute (most sessions are 30 minutes).

1. Decreased DOMS

If leg day is your worst nemesis and the squat rack has you crawling up the stairs for two to three days after the peach pump has faded, we’ve got some good news: The health benefits of saunas include better workout recovery. In a study. published in Springerplus, both traditional steam saunas and infrared saunas decreased DOMs and improved exercise recovery.

The researchers suggest that infrared saunas may penetrate the neuromuscular system to promote recovery. Plus, one study published in the Journal of Human Kinetics found that sitting in the sauna for 30 minutes increases women’s levels of human growth hormone (HGH), which helps our bodies break down fats and build muscle.

Just remember that you’ll need to rehydrate even more after.

2. Better Blood Pressure

Over half of all Americans experience high blood pressure at some point in their lives, according to the American Heart Association. But according to a study. published in Journal of Human Hypertension, even a single use of the sauna could help lower your blood pressure.

In the study, 100 participants took turns sitting in a sauna for 30 minutes; immediately after getting out of the sauna, their average systolic blood pressure (the top number) lowered from 137 mmHg to 130 mmHg, and their average diastolic blood pressure (the bottom number) lowered from 82 mmHg to 75 mmHg. Plus, their systolic blood pressure remained low for 30 minutes post-sauna, which the researchers says suggests s long-term blood pressure benefit of sauna usage.

That’s because the heat from a sauna causes blood vessels to dilate, which in turn causes a faster, better-timed blood flow, explains Caroline Robinson, M.D., a physician with Northwestern Memorial Hospital South Loop.

If you want to give it a go, just make sure to talk to your doctor beforehand, because saunas are not advised for people who suffer from high blood pressure, and other heart-related illnesses, she says.

3. A Stronger Ticker

Get this: In a Journal of Human Hypertension study, men and women’s heart rates also increased as much as they would have if they were performing medium-intensity exercise like jogging, cycling, or hiking. That doesn’t mean you should ditch your workout, but it does mean a few minutes of heat could give your heart some extra exercise, Robinson says.

That partly explains why research from the University of Finland shows that saunas help reduce the risk of early death from heart attack, stroke, and cardiovascular disease. For the study, researchers found that the more often men went to the sauna, and the longer they stayed, over a period of 20 years, the lower their risk for sudden cardiac death and fatal cardiovascular disease. While researchers looked at men, specifically, the results are promising for women, too, says Hokemeyer.

4. A Healthier Noggin

Take your clothes off. Get sweaty. Boost your memory? Sex can’t, but saunas might. Or at least according to research recently published in the journal Age and Ageing.

In the study, men who sat in a sauna multiple times per week had a 65 percent lower risk of developing dementia and Alzheimer’s disease than those who used them only once a week. The researchers say this could be connected to increased blood flow to the brain. That makes sense, because research has previously linked decreased blood flow to the brain with cognitive decline and dementia.

This study suggests that, to really get the brain boost, sauna sessions should become a regular habit.

5. Pain Relief

Lady Gaga swears by saunas for dealing with her chronic pain, and actually built one for herself at home.

Research suggests she’s onto something. For example, one study in the Journal of Alternative and Complementary Medicine examined the use of saunas to help relieve pain and treat the symptoms of chronic tension-type headache, frequent headaches that occur more than 15 days per month. After eight weeks of sauna exposure, the 37 participants reported a significant improvement in headache intensity. The study was small, but the results suggest that regular sauna bathing is a simple way to reduce some types of chronic pain.

6. Improved Immunity

Sit in the sauna and skip the flu shot? Sorry, it doesn’t work quite like that. But saunas can help you build a stronger immune system. In fact, in one study. published in the Journal of Human Kinetics, athletes who spent 15 minute in the sauna experienced an immediate increase in their white blood cell count, a marker for immune strength.

However, it’s important to note this immunity-boosting effect was higher in regular exercisers than in non-exercisers, so the sauna really shouldn’t be the only way you sweat.

7. Better Mental Health

The people you see sitting in your gym's sauna sure look relaxed, don’t they? While you can’t exactly sweat your stress away, according to New York City-based therapist, Kathryn Smerling, Ph.D., saunas can be a relaxing escape for many people. “They are warm, quiet, enclosed, and make you feel safe and relaxed in the way you would if you were nesting,” she says.

One study published in Psychosomatic Medicine even found that daily sauna sessions improved ratings of relaxation in patients with depression. Anytime you can escape the world for a moment of peace and quiet, it's going to have a positive effect on your mental health and stress she says. That’s why she regularly prescribes sauna usage to her patients who like and can tolerate the heat.

“If you choose to sauna, don’t go in with any judgements or expectations,” she says. You won’t leave the sauna a new person, and the benefits may hardly be noticeable at first for some, but over time, they can have a real impact on your mental health.”

8. Easier Weight Loss

To be clear, saunas will only help you lose water weight—not body fat. "They are valuable to one's weight loss plan by enabling the person to relax and recover, and to establish a more conscientious and healthy relationship with their body,” says Hokemeyer.

9. Lower Cholesterol

If a recent doctor visit has you trying to lower your cholesterol, consider hitting the sauna for some extra help. One study published in the International Journal of Occupational Medicine and Environmental Health found that when subjects used a sauna every other day for 20 days, they decreased their total cholesterol levels. The researchers concluded that the sauna offered cholesterol benefits similar to what could be expected from moderate-intensity physical exercise.

Again, that’s not to say that you should ditch your regular workout routine, because there is not a true substitution for exercise, according to Robinson.

But it is a reason to book some regular roasting appointments.