Heat · Sweat · Hydrate · Recover
Sauna Recovery for Athletes
How runners, lifters, team-sport and endurance athletes can fit sauna around training, what the performance research actually shows (and doesn't), and how to rehydrate so heat helps rather than drains you.
The Short Answer
Sauna can be a useful recovery tool for athletes, especially after endurance training. In one small study, runners who sat in a sauna after training for about three weeks increased their plasma volume and ran longer before exhaustion. But training sweat and sauna sweat stack up, so rehydrate with fluids and sodium, and keep heat lighter before competition.
Why Athletes Use Sauna
Athletes reach for the sauna for a few reasons: to wind down after a hard session, to relax tight muscles, to build heat tolerance before a hot race, and simply because it feels good. Much of that is about comfort and routine, which matter. The performance side is more specific, and the evidence is smaller than social media suggests. For the general before, during and after of a session, see our sauna recovery guide.
What the Research Shows (and Its Limits)
Endurance: the plasma-volume study
The study most often quoted is Scoon and colleagues (2007). Six male distance runners sat in a sauna at around 90°C for about 31 minutes after training, for roughly 12–13 sessions over three weeks. Compared with their normal training, time to exhaustion in a running test rose by 32%, which the authors estimated equals about a 1.9% improvement in an endurance time trial. Plasma volume, the fluid part of the blood, rose by 7.1%, which may help explain the result.
It's a useful, interesting result, but it's six people. Treat it as a promising signal, not a guarantee.
Heat adaptation, including in women
Repeated heat exposure helps the body adapt to heat, which matters if you're racing somewhere hot. A small study by Mee and colleagues (2018) looked at nine women. Those who spent 20 minutes in a 50°C environment wearing a sauna suit (a simulated sauna) before each session of a five-day heat acclimation programme expanded their plasma volume more (about 9% versus 1%) than with heat acclimation alone. Again, small, but encouraging for women who often get left out of this research.
What we don't know yet
A 2025 systematic review pulled together the research on sauna and athletic performance. Its conclusions were cautious: acute effects (sauna right before or after a single session) are uncertain; regular post-exercise sauna may improve running performance in hot conditions; and there was no clear effect on cycling performance or VO2max. The evidence was rated low to moderate quality. So sauna is a reasonable tool to add, not a shortcut.
When to Sauna Around Training
| Training day | Sauna? | Notes |
|---|---|---|
| Easy run, ride or swim | Yes, after | 15–30 min, moderate heat; good heat-adaptation day |
| Long or hard endurance session | Optional, after, shorter | You're already depleted; rehydrate first, keep it short |
| Strength / hypertrophy | Yes, after | Fine for winding down; skip cold plunge straight after if building muscle |
| Rest day | Yes | A good day for a longer, relaxed session |
| Day before a race or game | Light or skip | Avoid big sweat losses before competition |
| Hot-weather race coming up | Planned block | A few weeks of post-training sauna can support heat adaptation; build gradually |
This is a general guide, not a training prescription. If you're working with a coach, plan heat into your training block together. For starter, regular and advanced session structures, see The Heat Recovery Protocol.
A note on cold plunges. If building muscle is your goal, skip the cold plunge straight after lifting. In a study by Roberts and colleagues (2015), regular cold water immersion after strength training blunted gains in muscle mass and strength over 12 weeks compared with active recovery. Cold is optional, and timing matters: keep it away from your lifting sessions.
Using sauna to make weight is risky and outside the scope of this post. Don't try to "sweat it off" before a weigh-in.
Sweat Stacks Up: Training + Sauna
A single sauna session can cost around half a litre of sweat. Add that to a long or hot training session, which on its own can cost far more, and you can finish the day well behind on fluid and sodium. Heavy and salty sweaters lose even more. The easiest way to find out where you sit is a simple weigh-in before and after training; our guide to why heavy sweaters need more sodium explains how. And if you regularly finish wrung out, read what happens when you sweat too much.
How Athletes Should Rehydrate
Start with an honest benchmark. Dr Stacy Sims suggests about 360–400mg of sodium (and around 200mg of potassium) per 16 oz (about 475ml) as an everyday target for rehydrating, and she cautions against very high-sodium drinks for most people. For most training days, that's plenty. A 700mg serve makes sense when the sweat really stacks up.
| Day | What usually works |
|---|---|
| Light training + short sauna | Water and a normal meal |
| Moderate training + sauna | Water plus half to one serve, mixed as directed on the pack |
| Long or hot training + sauna, heavy or salty sweater | A full serve (700mg sodium), plus water and a salty meal; spread fluids over the next few hours |
That full-serve row is where Saunabodi Electrolytes fit: 700mg sodium, 250mg potassium and 60mg magnesium per stick, 0g sugar, mixed as directed on the pack. It's an ORS-inspired blend that also includes vitamin C, L-citrulline, taurine and glycine. For more on choosing a drink, see our guide to the best electrolytes for sauna recovery and why high-sodium electrolytes matter.
Signs to Ease Off
- Dizziness or light-headedness
- Headache
- Cramping
- Unusual fatigue or heavy legs that don't lift
- A resting heart rate that stays higher than usual
If these show up, shorten or skip sauna, rehydrate, and back off training for a day. See why sauna can cause headaches or dizziness and signs of electrolyte depletion after sauna.
Women Athletes: What Changes
Your cycle can change how heat feels. In the luteal phase (the second half of the cycle), core temperature is slightly higher and plasma volume can drop by up to 8%, so heat may feel harder work. Dr Stacy Sims suggests sauna about 25–30 minutes after a workout, or at the end of the day, and keeping the temperature around 74°C (165°F) or below unless you're experienced. And as the Mee study above showed, women do adapt to heat. For perimenopause and menopause, see our women's health guide.
Who Should Check With a Doctor First
Talk to your doctor before using sauna if you have a heart, blood pressure or kidney condition, take medication that affects fluid or sodium balance, have a history of heat illness, or feel unwell. If you're pregnant, talk to your clinician before using heat.
This article is general information, not medical advice. If you have a heart, blood pressure or kidney condition, take regular medication, or are pregnant, check with your doctor before using a sauna.
FAQ
Is sauna good for athletes' recovery?
Sauna can help athletes relax and wind down, and small studies suggest regular post-training sauna may support heat adaptation and endurance. The evidence is promising but limited, so treat it as a useful tool rather than a shortcut.
Should you use a sauna before or after a workout?
After is usually best. Sauna before training can leave you hot and short on fluid before you start, while sauna after training fits recovery and is how most studies used it.
Does sauna improve endurance performance?
In one small study, runners who used a sauna after training for three weeks ran 32% longer before exhaustion and increased their plasma volume. A 2025 review found regular post-exercise sauna may help running in hot conditions, but the evidence is low to moderate quality.
Does sauna after lifting hurt muscle gains?
There's no good evidence that sauna after lifting hurts gains, and it's fine for winding down. Cold water immersion straight after strength training is different: one study found it blunted muscle and strength gains, so skip the cold plunge if building muscle is the goal.
How long should athletes stay in a sauna after training?
Around 15–30 minutes at moderate heat suits most athletes, and shorter after a long or hard session. Build up gradually and get out if you feel dizzy or unwell.
Do athletes need electrolytes after sauna?
After light training and a short sauna, water and a normal meal are usually enough. When long or hot training and sauna stack up, or you're a heavy or salty sweater, a drink with sodium helps replace what you've lost. Using infrared? See how much you sweat in an infrared sauna.
Should you use a sauna the day before a race or game?
Keep it light or skip it. You want to start competition fully hydrated, so avoid big sweat losses the day before.
The Bottom Line
Sauna can earn a place in an athlete's week, especially after easy sessions and in the lead-up to a hot race. Keep it lighter before competition, keep cold away from lifting, and rehydrate for the whole day's sweat. For the days training and sauna stack up, Saunabodi Electrolytes are there; you can try the variety pack.
Stay Hot. Stay Hydrated.
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Sources
- Scoon GSM, Hopkins WG, Mayhew S, Cotter JD. Effect of post-exercise sauna bathing on the endurance performance of competitive male runners. Journal of Science and Medicine in Sport, 2007
- Mee JA, et al. Sauna exposure immediately prior to short-term heat acclimation accelerates phenotypic adaptation in females. Journal of Science and Medicine in Sport, 2018
- Sauna bathing and athletic performance: a systematic review, 2025
- Roberts LA, et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. Journal of Physiology, 2015
- Hannuksela ML, Ellahham S. Benefits and risks of sauna bathing. American Journal of Medicine, 2001
- Dr Stacy Sims: Sweltering Sauna or Cold Plunge?
- Dr Stacy Sims: Women-specific sauna guidance
- Dr Stacy Sims: How much sodium and potassium do you need to rehydrate? (YouTube)
Stay Hot. Stay Hydrated. We live in the heat.
