Will regular sauna sessions raise your HRV?
Sauna After Your Workout Won't Boost Your HRV, an 8-Week Trial Finds
· By Anthony Falcone
Verdict: Drop it. If HRV is the reason you sauna, drop that reason: adding a post-workout sauna gave no extra HRV benefit over exercise alone. Exercise did the work.
What the researchers tested
In Finland, sedentary office workers with at least one risk factor for heart disease (most often obesity or raised blood pressure) were split into three groups: exercise plus sauna, exercise only, or carry on as usual.
The exercise was an hour, three times a week: warm-up, 20 minutes of resistance work and 30 minutes of cycling. The sauna group then sat for 15 minutes in a dry sauna that started at 65 °C and went up 5 °C every two weeks.
Heart rate variability (HRV), a common marker of how well your nervous system recovers, was measured lying down, fasted, before and after the eight weeks.
What they found
Exercise changed some heart-rate measures compared with doing nothing. Adding the sauna made no difference on any of the seven HRV measures.
The researchers had expected the opposite. Their conclusion: regular sauna may affect HRV a little, but probably not much, and exercise is the cornerstone.
Worth knowing: the same team previously reported from this trial that exercise plus sauna improved fitness and systolic blood pressure more than exercise alone. So the sauna isn't useless — it just isn't an HRV tool.
What this means for you
- Want better HRV? Train consistently. That's what moved the needle here.
- Keep the sauna for what it may do well — relaxation and, possibly, blood pressure and fitness alongside exercise — not as an HRV hack.
- Sitting in a hot sauna straight after a hard session is extra strain. Build up temperature and time gradually, like this trial did.
How much to trust it
- Data from nine participants had to be left out, leaving a modest sample.
- Most participants were middle-aged women, many with obesity; menopause and menstrual cycle weren't controlled for.
- There was no sauna-only group, so exercise effects may have masked sauna effects.
- HRV came from 5-minute recordings, not 24-hour monitoring.
The study
Lee E, Ketelhut S, Wiklund P, Kostensalo J, et al. Regular postexercise sauna bathing does not improve heart rate variability: A multi-arm randomized controlled trial. Physiological Reports, 2025. doi.org/10.14814/phy2.70449
Our HRV & Stress Protocol shows you how to measure HRV properly and which daily habits are most likely to move it. See the protocol