Sauna does not lower your heart rate during a session. It raises it significantly, sometimes to 120 to 150 beats per minute, similar to moderate aerobic exercise. However, the recovery period after a sauna session and the long-term effects of regular sauna use tell a more interesting story, with potential benefits for your cardiovascular system over time.
What Happens to Your Heart Rate During a Session
When you sit in a sauna, your body treats the heat as a physical stressor. Your cardiovascular system kicks into high gear: cardiac output increases by 60% to 70%, and your circulatory system redirects 50% to 70% of blood flow from your core to your skin to help you cool down through sweating. To keep up with this demand, your heart beats faster.
How much faster depends on the temperature and how long you stay. In a study of 20-minute sessions, women in an 80°C (176°F) sauna averaged a heart rate of about 114 beats per minute afterward, while those in a 120°C (248°F) sauna averaged around 121 bpm, with some participants reaching as high as 155. A separate study found that a 30-minute session at 75°C raised heart rate by about 16 beats per minute on average. These numbers are comparable to what you’d see during a brisk walk or easy bike ride.
Your nervous system drives this response. During a sauna session, the “fight or flight” branch of your nervous system ramps up while the calming, rest-and-digest branch dials down. This is the same pattern your body follows during exercise. Blood pressure also shifts: diastolic pressure (the bottom number) tends to drop as blood vessels widen from the heat, even as your heart rate climbs.
The Recovery Period Is Where Things Get Interesting
About 30 minutes after leaving the sauna, your body doesn’t just return to normal. Research shows that markers of parasympathetic nervous system activity (the calming branch that slows your heart and promotes recovery) actually rise above where they were before the session. In other words, your heart rate doesn’t just come back down. Your nervous system temporarily shifts into a more relaxed state than your baseline.
This rebound effect is one reason sauna bathing is often compared to exercise. Both stress the cardiovascular system in the short term, then leave it in a calmer state afterward. One study directly compared a standalone 30-minute sauna session with a combined exercise-plus-sauna session and found the cardiovascular responses were remarkably similar. Both produced comparable drops in blood pressure and increases in heart rate, and the sauna-only group actually returned to baseline faster.
Can Regular Sauna Use Improve Resting Heart Rate?
This is likely the question behind the search, and the answer is: possibly, but the evidence is mixed. The theory is straightforward. If sauna use trains your cardiovascular system the way exercise does, repeated sessions should improve your resting heart rate and heart rate variability (HRV), a measure of how well your nervous system regulates your heart. Higher HRV generally signals a healthier, more adaptable cardiovascular system.
A six-week sauna program improved autonomic nervous system function in one study, and two weeks of daily 15-minute sessions improved HRV in patients with heart failure. But a more recent randomized controlled trial found that adding regular sauna sessions after exercise did not improve HRV compared to exercise alone in healthy adults. Another study found HRV unchanged after 10 days of combined exercise and sauna use. The benefits may depend on your starting fitness level, how often you go, and whether you have an existing cardiovascular condition.
What the research does show convincingly is that frequent sauna use is associated with better long-term cardiovascular outcomes. A large Finnish study tracking over 2,000 men found that those who used a sauna four to seven times per week had a 50% lower risk of dying from cardiovascular disease and a 48% lower risk of fatal coronary heart disease compared to those who went once a week. Even two to three sessions per week reduced cardiovascular death risk by 27%. These are associations, not proof of cause, but the size and consistency of the effect is striking.
How Sauna Compares to Exercise
The cardiovascular stress of a sauna session is genuinely similar to moderate aerobic exercise. Your heart rate rises into a comparable range, your blood vessels dilate, and your body works to maintain temperature regulation. One key difference: during exercise, your muscles are consuming oxygen and generating metabolic demand. In a sauna, the demand comes entirely from heat management. You’re getting a cardiovascular workout without the mechanical stress on your joints, muscles, and tendons.
This makes sauna bathing particularly relevant for people who have difficulty exercising, whether due to injury, chronic pain, or mobility limitations. The heart still gets challenged. That said, sauna is not a full replacement for exercise. It doesn’t build muscle, improve coordination, or provide the same metabolic benefits as physical activity.
Temperature and Duration That Matter
Most research on cardiovascular effects uses traditional Finnish sauna conditions: temperatures between 75°C and 100°C (167°F to 212°F) with sessions lasting 15 to 30 minutes. Higher temperatures produce larger heart rate increases. At 120°C, heart rates climb higher, peak heart rates are more extreme, and some participants in one study briefly entered what researchers classified as a maximum effort heart rate zone, something that didn’t happen at 80°C.
For most people, 15 to 20 minutes at 80°C to 100°C produces a meaningful cardiovascular response without pushing into uncomfortable territory. Starting with shorter sessions and gradually increasing time is a practical approach if you’re new to sauna use.
Who Should Be Cautious
Sauna bathing is safe for most people, including many with stable heart conditions. But there are clear contraindications. People with unstable angina, a recent heart attack, or severe aortic stenosis should avoid the sauna. Decompensated heart failure and cardiac arrhythmias are also reasons for caution. Older adults prone to drops in blood pressure when standing should be careful, since the blood pressure decrease from a sauna session can cause fainting, particularly right after stepping out. Staying hydrated and standing up slowly after a session reduces this risk considerably.