Three weeks of post-training sauna bathing raised treadmill run time to exhaustion by 32% in competitive male runners. Plasma volume rose 7.1% over the same period (Scoon et al., Journal of Science and Medicine in Sport, 2007, retrieved August 2026).
This guide covers what athletes and trainers do with sauna heat, and which sauna recovery benefits the peer-reviewed evidence supports. If you're new to sauna, our beginner's guide to sauna covers how to structure a first session.
Key Takeaways
- Repeated post-training sauna improves endurance. Three weeks of it raised run time to exhaustion by 32% and plasma volume by 7.1% in trained runners (Scoon et al., 2007).
- Evidence for easing next-day soreness is mixed: a 2025 review of 14 studies found four showing a benefit and four showing none.
- Cold water immersion after strength training measurably reduces muscle and strength gains. No study has found the same for sauna heat.
- Take the heat after training.
- Replace around 150% of the fluid you lose, with sodium (Shirreffs et al., 1998).
does a sauna help with muscle recovery?
For soreness, the evidence is thin. A 2025 systematic review covered 14 studies and 194 participants. Four reported a benefit for delayed onset muscle soreness, four reported no effect, and one reported an adverse result (Sports Medicine – Open, 2025, retrieved August 2026).
A Bayesian network meta-analysis published in June 2025 was more favourable. Heat treatment produced significant effects on soreness against placebo within the first 48 hours after exercise, with the effect fading after that window (Journal of Pain Research, 2025, retrieved August 2026).
Protocols across those 14 studies ranged from 36°C to 105°C and 10 to 40 minutes, and the reviewers rate the underlying research as low to moderate quality. Heat may change how sore you feel in the first day or two. There isn't an agreed dose yet.
what does regular sauna do for endurance?
The endurance evidence is stronger, and it works through blood volume. Six competitive male runners added post-training sauna sessions for three weeks, around 31 minutes at 89.9°C, roughly 12 sessions in total. Run time to exhaustion rose 32%, which modelled out to a 1.9% improvement over 5km (Scoon et al., 2007, retrieved August 2026).
Plasma volume rose 7.1% across the same three weeks. More plasma means more blood available to move heat to the skin and oxygen to working muscle, so the cardiovascular cost of a given pace drops. A separate trial in well-trained cyclists used 30-minute sauna exposures at 87°C, taken immediately after training. Plasma volume peaked at 17.8% above baseline after only four of them, and waking heart rate fell about 10% (European Journal of Applied Physiology, 2015, retrieved August 2026).
There is Australian data on the same adaptation. Fifteen semi-professional Australian Rules footballers completed a six-week programme of passive hot water immersion. Intermittent running performance improved from 19.9 to 20.8 km/h, with plasma volume expansion alongside it (PLoS ONE, 2022, retrieved August 2026). That study used hot water instead of a sauna, and it produced the same plasma volume expansion.
The gains are specific. The same 2025 systematic review found no effect on VO2max or on cycling performance (Sports Medicine – Open, 2025, retrieved August 2026). What improves is heat tolerance and how long you can hold a pace.
should you use a sauna or an ice bath after training?
It depends what the training is for. Twelve weeks of post-workout cold water immersion held quadriceps muscle growth to around 2%, against roughly 15% for men doing active recovery instead. Leg press strength rose 42% against 59%. Knee extension came in at 21% against 39%, and isometric knee extensor strength at 10% against 26% (Roberts et al., The Journal of Physiology, 2015, retrieved August 2026). Every measured outcome favoured active recovery.
No study has found the same effect for sauna heat. Head-to-head trials of sauna against cold water immersion are still sparse, so the case for heat rests on what cold does to strength gains.
If you lift for size or strength, an ice bath straight after the session works against what you turned up for. Sauna is the safer choice on those days. Cold water immersion still helps when you need to feel fresh for a game tomorrow.
when should you use the sauna around training?
Afterwards, in most cases. Every study showing a performance benefit above applied heat following the training session, usually within about 15 minutes of finishing. That timing keeps the cardiovascular load in one block and lets the training itself run at full quality.
One 2015 trial put the sauna first. Fifteen minutes at 76.7 to 82.2°C before eccentric exercise reduced the strength and range-of-motion deficits over the following week (Asian Journal of Sports Medicine, 2015, retrieved August 2026). That design hasn't been widely replicated.
For ordinary training, heat beforehand adds thermal and cardiovascular load before you've lifted anything. The exception is a deliberate heat acclimation block in the weeks before racing somewhere hot.
how much should you drink around a sauna session?
Enough to keep fluid loss under 2% of your body mass. Past that point, power output drops and heat illness risk climbs (American College of Sports Medicine position stand, retrieved August 2026). A sauna on top of a hard session brings you closer to that threshold.
To rehydrate properly, drink around 150% of the fluid you've lost, and include sodium (Shirreffs, Taylor, Leiper & Maughan, American Journal of Physiology, 1998, retrieved August 2026). Some of what you drink leaves as urine before it's absorbed, so matching losses one for one leaves you short.
Weigh yourself before and after a session if you want a number that applies to your body and your sauna. Our sauna aftercare routine covers the rest of that window, including how long to spread the fluid over.
| Outcome | What the research shows | Strength |
|---|---|---|
| Endurance and heat adaptation | 32% longer run time to exhaustion and 7.1% more plasma volume after three weeks | Good, on small samples |
| Delayed onset muscle soreness | Mixed. Four of 14 studies positive, four null, one adverse. Some effect inside 48 hours | Weak |
| Protecting strength and size gains | Cold water immersion measurably reduces them. No study has found the same for heat | Moderate, and indirect |
| VO2max and cycling performance | No effect found in the 2025 systematic review | Clear null result |
how to build a sauna recovery routine
The sauna recovery benefits with evidence behind them come from repetition. The protocols are ordinary. Take the heat after training, 15 to 30 minutes at 80 to 90°C, two or three times a week. Split it across two sittings with a break between them, and rehydrate as above. Give it three weeks before you judge whether it's working, since that's how long the adaptations took to show up in the studies.
Every study above was run on healthy, trained adults. If you're pregnant, or you have a heart condition, low blood pressure or a history of heat intolerance, talk to your doctor before adding sauna sessions on top of hard training.
Your scalp and ears heat faster than the rest of you, and once your head is uncomfortable the session ends early regardless of what your legs need. A densely felted merino hat slows heat transfer to the head, so 20 minutes stays manageable. Our guide to the benefits of a sauna hat covers the mechanism, and why merino wool is the gold standard covers the fibre.
When we developed the FELT. hats we tested a spread of thicknesses and settled on 4mm as the practical middle: enough insulation for a long session, light enough to dry between uses. Both The Classic and The Modern use it. Airing a hat out after a session is usually all the care it needs.
For the wider setup around those sessions, see our complete guide to setting up a home sauna routine. The essential home sauna accessories checklist covers what else is worth having. Our guide to the science-backed health benefits of sauna covers the cardiovascular and sleep research beyond recovery.
common questions about sauna and recovery
can a sauna reduce delayed onset muscle soreness?
The evidence is mixed. A 2025 systematic review of 14 studies found four reporting a benefit, four reporting no effect, and one reporting harm. A 2025 meta-analysis did find a significant effect against placebo within the first 48 hours after exercise. Heat may change how sore you feel in the short term, and the research base behind that is rated low to moderate quality.
is a sauna better than an ice bath after a workout?
For strength and muscle growth, yes. Twelve weeks of cold water immersion after resistance training held quadriceps growth to around 2% against 15% for active recovery, and leg press gains to 42% against 59% (Roberts et al., 2015). No study has found the same effect for sauna heat. Cold water immersion is still useful when you need to feel fresh for competition the next day.
how long should you sit in a sauna after training?
The studies showing endurance benefits used roughly 30 minutes at 87 to 90°C, usually split across two sittings. For most people 15 to 30 minutes at 80 to 90°C, two or three times a week, is a reasonable target. Keep total fluid loss under 2% of body mass.
how soon after exercise should you use the sauna?
Within about 15 minutes of finishing, which is the timing used in the trials that produced plasma volume expansion and endurance gains. Using the sauna beforehand raises cardiovascular and thermal load with no documented benefit for ordinary training, though it has a place in deliberate heat acclimation ahead of racing in hot conditions.
do you need a sauna hat for recovery sessions?
No. It does make longer sessions more comfortable. Your scalp and ears heat faster than the rest of your body, so head discomfort often ends a session before your recovery time is up. A densely felted merino hat slows that heat transfer, which is what lets you sit the full 20 minutes.
