Regular sauna sessions can genuinely improve endurance performance by expanding plasma volume, sharpening thermoregulation, and supporting recovery after training, though the gains are modest and sauna works best as a complement to structured training rather than a stand-in for it.
The short answer is yes, but not for the reasons most people assume. Sauna use won't replace your training sessions or magically increase your VO2 max overnight. What it does—backed by a growing body of research—is create physiological adaptations that can complement your training and potentially improve endurance performance.
Let's break down what the science actually says.
How Heat Exposure Changes Your Body
When you sit in a sauna, your body temperature rises. That triggers a cascade of responses that, over time, can benefit athletic performance.
Plasma volume expansion. This is the most well-documented effect. Regular heat exposure increases your blood plasma volume by 10 to 20 percent (Stanley et al., 2015, Journal of Science and Medicine in Sport). More plasma means your heart doesn't have to work as hard to pump blood during exercise. Your stroke volume increases. Your heart rate stays lower at the same workload. That translates directly to endurance improvements, especially in hot conditions.
One study had competitive runners add 30-minute sauna sessions twice per week for three weeks. Their plasma volume increased by 7 percent. Their time to exhaustion in a hot environment improved by 32 percent (Scoon et al., 2007, European Journal of Applied Physiology). That is not a small bump.
Heat shock protein production. Heat exposure activates heat shock proteins (HSPs), which help repair damaged proteins in your cells. For athletes, this matters because intense exercise creates cellular stress. HSPs help your muscles recover and adapt to training. They also improve your body's ability to handle future heat stress, which is why athletes who train in heat acclimatize faster after sauna exposure.
Improved thermoregulation. Your body gets better at cooling itself. You start sweating earlier in exercise, your sweat becomes more dilute (meaning you conserve electrolytes), and blood flow to your skin becomes more efficient. For endurance athletes racing in warm conditions, this is a meaningful advantage.
What the Research Shows for Specific Outcomes
Endurance performance. A 2021 meta-analysis in Sports Medicine reviewed 11 studies on post-exercise sauna use. The researchers found that regular sauna sessions improved endurance performance markers, including time to exhaustion and perceived exertion at submaximal workloads. The effect was strongest when sauna sessions were done 2 to 3 times per week for at least 2 weeks.
Muscle recovery. Heat therapy increases blood flow to muscles, which can speed up clearance of metabolic waste products like lactate. Some research suggests sauna use after training reduces muscle soreness and improves recovery markers, though the evidence is mixed. A 2019 study in Journal of Strength and Conditioning Research found that post-workout sauna sessions reduced perceived muscle soreness in recreational athletes but did not improve objective measures of muscle function recovery.
Cardiovascular adaptations. The cardiovascular system adapts to heat stress similarly to how it adapts to moderate exercise. Your heart rate increases, blood vessels dilate, and your body learns to manage increased blood flow demands. Over time, this can improve resting heart rate and blood pressure. Finnish men who sauna 4 to 7 times per week have a 40 percent lower risk of dying from cardiovascular disease compared to weekly users (Laukkanen et al., 2015, JAMA Internal Medicine). That is not a direct performance benefit, but better cardiovascular health supports better training outcomes.
The Practical Protocol
If you want to use sauna for athletic performance, here is what the research suggests works.
Timing matters. The most studied approach is post-exercise sauna use. You are already hot, your body is primed for adaptation, and the heat stress builds on your training stimulus. Some athletes use sauna immediately after training. Others wait 10 to 15 minutes to cool down first. Both approaches have evidence behind them.
Frequency and duration. Two to three sessions per week, lasting 15 to 30 minutes each, appears sufficient to trigger plasma volume expansion and heat adaptation. More frequent sessions may produce faster results, but the difference is marginal after the first few weeks.
Temperature range. Most studies use dry saunas at 80 to 100 degrees Celsius (176 to 212 degrees Fahrenheit). Infrared saunas operate at lower temperatures (45 to 60 degrees Celsius) but produce similar physiological effects over longer sessions. The key variable is that your core temperature rises by about 1 to 2 degrees Celsius during the session.
Hydration is not optional. You will lose significant fluid through sweat. Weigh yourself before and after a session. Drink enough to replace what you lost. A 2 percent body weight loss from dehydration can impair performance. A 4 percent loss can be dangerous.
What Sauna Does NOT Do
Let's clear up a few myths.
- Sauna does not build muscle.
- It does not improve strength.
- It does not increase power output.
Those adaptations come from resistance training and proper nutrition.
Sauna does not replace endurance training. The plasma volume expansion helps, but your cardiovascular system still needs the specific stimulus of running, cycling, or swimming to improve.
Sauna does not "flush toxins" from your muscles or speed recovery to the point that you can skip rest days. It may help with recovery, but it is a supplement to good sleep, nutrition, and active recovery, not a replacement.
Who Should Be Cautious
If you have low blood pressure, heart conditions, or are on medications that affect heart rate or blood pressure, check with your doctor before starting a sauna protocol. The same goes for anyone who has ever had heat stroke or heat exhaustion. Sauna use is safe for most healthy men, but it is a stressor on the body. Treat it like one.
Athletes competing in hot environments should also be careful not to overdo sauna sessions during their competition season. The goal is adaptation, not exhaustion. If your training already includes hard sessions in the heat, adding sauna might push your recovery capacity past its limit.
The Takeaway
Regular sauna sessions can improve endurance performance by expanding plasma volume, improving thermoregulation, and supporting recovery. The effect is real but modest—think a few percent improvement in time to exhaustion, not a dramatic transformation.
The best approach is to treat sauna as a training tool, not a shortcut. Use it 2 to 3 times per week, post-workout, stay hydrated, and pay attention to how your body responds. If your goal is to perform better in hot conditions or to squeeze a bit more out of your endurance training, it is worth adding to your routine.
If your goal is to get faster, stronger, or fitter, do the actual training first. Sauna is a complement, not a substitute.
Frequently asked questions
how often should you use a sauna to improve athletic performance
Two to three sessions per week, each lasting 15 to 30 minutes, appears sufficient to trigger plasma volume expansion and heat adaptation. Post-exercise use is the most studied approach, since your body is already primed for adaptation after a workout. More frequent sessions may produce faster results, but the difference is marginal after the first few weeks.
does sauna use increase plasma volume
Yes, regular heat exposure is well-documented to increase blood plasma volume. One study had competitive runners add 30-minute sauna sessions twice per week for three weeks, and their plasma volume increased by 7 percent. More plasma means the heart doesn't have to work as hard during exercise, which can directly support endurance performance.
can sauna sessions reduce muscle soreness after training
The evidence is mixed. A 2019 study in the Journal of Strength and Conditioning Research found that post-workout sauna sessions reduced perceived muscle soreness in recreational athletes, but did not improve objective measures of muscle function recovery. Heat therapy does increase blood flow to muscles, which may help clear metabolic waste products like lactate.
is sauna use safe for men with heart conditions
Men with low blood pressure, heart conditions, or medications that affect heart rate or blood pressure should check with a doctor before starting a sauna protocol. The same caution applies to anyone who has previously experienced heat stroke or heat exhaustion. Sauna is a genuine stressor on the body and should be treated as one.