In October, NPR ran a story with the headline "From floating saunas to clinical trials: How heat might help mental health." The researchers in it were excited and careful at the same time. One of them said the field is "very much at the beginning." That's a good way to frame the question many of us ask in the locker room: if I already did the work, does 15 minutes in the sauna afterward add anything?

The short answer: maybe, for blood pressure. Probably not much for weight loss. And the evidence is thinner than the hype. Here is what the trials actually found.

The best test so far: exercise vs. exercise plus sauna

Most sauna research is observational. Finnish men who sauna often live longer, but they may also be the people with time, money and lower stress. To test whether the sauna does anything after training, you need a trial that gives two groups the same workout and adds heat for only one of them.

That is what Lee and colleagues did in a 2022 randomized trial in the American Journal of Physiology. They enrolled sedentary adults (average age 49) who each had at least one cardiovascular risk factor. Participants trained three times a week for eight weeks. Each 60-minute session included 20 minutes of resistance work and 30 minutes of cycling. One group then sat in a sauna for 15 minutes, starting at 65°C and rising to 75°C over the study. A second group did the same exercise with no sauna, and a third group stayed sedentary.

  • Systolic blood pressure: the exercise-plus-sauna group dropped from 134 to 126 mmHg. The exercise-only group stayed at 134. The between-group difference was −8.0 mmHg (95% CI −14.6 to −1.4). Diastolic pressure did not differ.

  • Fitness: VO2max improved 2.7 mL/kg/min more with sauna than with exercise alone.

  • Total cholesterol: about 19 mg/dL lower with sauna than with exercise alone.

  • Body fat: no extra benefit from the sauna.

For context, an 8-mmHg drop in systolic pressure is roughly what you would expect from a first blood pressure medication. That is a meaningful number. It came from a small trial, though, so read the next section before you make it your whole plan.

What it can't tell you

Each arm had only about 15 people, and the confidence interval runs from a large effect (14.6 mmHg) to a trivial one (1.4 mmHg). About 87% of participants were women. People taking cardiovascular medication were excluded, and diet wasn't controlled. There was no sauna-only group, so the trial can't separate "sauna after exercise" from simply "sauna." It is one promising trial, not settled science.

The weight-loss question

A 2026 trial in the Turkish Journal of Kinesiology tested heat in a different way. Ajhar and colleagues randomized 60 adults with obesity to 12 weeks of aerobic exercise five days a week, the same exercise plus 15–20 minutes in a 55°C Finnish sauna, or no program.

Both exercise groups improved a lot, and the sauna added close to nothing. Body weight fell 8.3% with exercise alone and 8.0% with sauna. LDL fell 14.5% and 13.5%. Resting heart rate fell 9.1% and 8.7%. The paper highlights a lower final weight in the sauna group, but that group started about 2 kg lighter. The study also has problems: it was registered after the fact, diet was tracked only informally, blood pressure wasn't measured, and one claim in the text conflicts with the paper's own table. The honest takeaway is that the sweat you lose in a sauna is water, and it comes back when you drink.

What about mood?

The NPR story centered on a 2016 trial. Thirty people with major depression got either a single session of whole-body heating to a core temperature of 38.5°C or a sham session. In the heated group, symptoms dropped noticeably within a week, and the effect lasted about six weeks. A 2026 meta-analysis of seven randomized trials (363 people) found a small-to-moderate effect of heat on depressive symptoms (g = 0.32). These were mostly clinical hyperthermia protocols, not a gym sauna, so treat this as a reason for curiosity, not a treatment plan.

The minimum effective dose

If you have access to a sauna and enjoy it, here is a version that stays close to what the trials used:

  1. Finish your workout first, so the heat doesn't take away from your training.

  2. Sit for 10–15 minutes at whatever temperature your gym runs. The Lee trial started at 65°C, and most gym saunas run hotter.

  3. Do it on training days, two or three times a week.

  4. Drink water afterward, and add electrolytes if you sweat heavily.

  5. Leave the moment you feel dizzy, nauseated or unwell. There is no prize for staying longer.

If you're also deciding whether to cold plunge after training, read our companion piece, Don't Ice the Gains: When Cold Plunges Help and Hurt. The timing tradeoffs are quite different for cold than for heat.

Safety first

Heat is a real stress on your heart and blood vessels. That is part of why it may work, and also why it isn't for everyone.

  • Hydration: you can lose a lot of fluid in a single session. Start hydrated and rehydrate afterward.

  • Blood pressure medication: drugs that lower blood pressure can combine with heat to cause dizziness or fainting. Stand up slowly.

  • Pregnancy: avoid raising your core temperature, especially in the first trimester. Ask your obstetric provider.

  • Alcohol: never combine alcohol with a sauna. It is linked to sauna deaths.

  • Heart conditions: unstable angina, a recent heart attack or severe aortic stenosis are reasons to stay out.

  • Talk to your doctor before adding heat if you have any cardiovascular condition or take regular medication. The trials above excluded many of those people.

A few things that help

You don't need gear to sauna. These are optional and low-cost.

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The bottom line

If you already exercise, a short sauna session afterward may give your blood pressure a small extra push, based on one good but small trial. It won't speed up fat loss. Keep it short, stay hydrated, and check with your doctor if you have any heart or blood pressure concerns. The workout is still the main event, and the sauna is a bonus.

Sources

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