Research reviewed: July 18, 2026 — every claim links to its source.

Sauna Before or After a Workout? What the Studies Actually Found

By the RecoveryGearHQ research team · How we research

The short answer is "after," and the honest answer is that the question is smaller than the internet makes it sound. Almost every article ranking for this phrase asserts that pre-workout sauna "impairs performance by 5–15%" or similar, with no study attached to the number. We went looking for the actual trials. There are fewer than a dozen worth reading, one of them is genuinely good, and one of them points the opposite direction from the consensus — which is exactly the kind of thing that gets left out when a sauna retailer writes the article.

1. The one trial that actually answers "after"

The best available evidence is Kirby et al. (2020), European Journal of Applied Physiology — 20 trained middle-distance and cross-country runners, 13 of them female, over a three-week trial. The sauna group entered a sauna within about five minutes of finishing their run and sat for 28 ± 2 minutes at 101–108 °C, three times per week. After roughly nine to ten sessions, compared against a control group whose training volume was statistically matched:

Source: Kirby NV, Lucas SJE, Armstrong OJ, Weaver SR, Lucas RAI, Eur J Appl Physiol 2020;121(2):621–635, PMC7862510, doi:10.1007/s00421-020-04541-z. Open access, read in full July 18, 2026.

A 12% improvement in time to exhaustion in three weeks is a large effect for a trained population, and the heat-adaptation markers moved in the direction you'd expect: cooler core temperature at the same workload, lower heart rate, more active sweat glands. This is a real result.

There is an earlier and frequently cited study — Scoon, Hopkins, Mayhew and Cotter (2007), Journal of Science and Medicine in Sport 10(4):259–262 — that used a similar post-exercise sauna protocol in six male runners and is where the widely repeated "7% plasma volume increase" figure originates. We could not retrieve that paper's full abstract from a primary source during this review (the publisher's page was inaccessible to us on July 18, 2026), so we are not repeating its effect sizes as verified. What we can verify is that Kirby et al. describe it directly: the reduction in exercise heart rate they observed "was likely mediated by increased plasma and/or blood volume, as was demonstrated using a similar post-exercise sauna bathing protocol by Scoon et al. (2007), though these variables were not measured in the current study." Note that second clause — Kirby et al. did not measure plasma volume. If you see the 8% VO₂max figure and the 7% plasma volume figure quoted as though they came from the same experiment, they didn't.

2. The case for "before" — and why it's thin

Here is where we part company with almost every other page on this topic. The standard claim is that pre-workout sauna reliably degrades strength. The single most directly relevant study found the opposite, and we think that study is weak — but you deserve to know it exists rather than reading a confident number with nothing behind it.

Bartolomé et al. (2022), IJERPH 19(17):10934 put 30 young men through a 12-minute dry sauna at 100 ± 3 °C immediately before a leg-press maximal-repetition test. Reported strength gain versus their earlier no-sauna test: +26.7 ± 33.5% (p < 0.05) in the untrained group and +11.0 ± 7.2% (p < 0.01) in the trained group. Taken at face value, that's a case for sauna before lifting.

They also cite an earlier study (Hedley et al., 70 °C for 30 minutes) that found roughly a 4% decrease in leg press — the opposite direction — and explain the discrepancy after the fact by appealing to thermal dose. We have not independently retrieved that paper and are reporting it only as cited within Bartolomé et al.

The broader literature on heating muscle before exercise is more measured than either camp. A systematic review and meta-analysis with meta-regression on muscle warm-up (Sports Medicine and Health Science, 2025) concluded that raising muscle temperature moderately improves fast-velocity force production and rate of force development, but not maximal force capacity. That is a useful frame: warming the muscle is not the same intervention as sitting in 100 °C air until your core temperature exceeds 39 °C, which is what happened in Bartolomé et al. and which is by definition hyperthermia.

Our read: nobody has run the study that would settle this — a randomized, counterbalanced crossover of sauna-before versus no-sauna on the same lifters with a directly measured 1RM. Until someone does, the honest position is that the pre-workout case is unproven in both directions, and the post-workout case has one decent trial behind it. If you only have time for one sauna session and you train for endurance, put it after.

3. What nobody has tested

Worth naming the gaps plainly, because most articles on this topic quietly imply they've been filled:

No study we found compares sauna-before against sauna-after in the same participants. The Kirby protocol's five-minute post-exercise window has never been tested against, say, a two-hour delay — so "you must get in immediately" is an extrapolation from one study's methods section, not a finding. Almost all of the heat-adaptation research is in endurance athletes; the effect of habitual post-lifting sauna on hypertrophy in resistance-trained people is essentially unstudied. And the sex-specific picture is thin everywhere, though Kirby et al. is better than most on this count with 13 female participants out of 20.

4. The protocol the evidence supports

If you want to copy something with published outcomes attached rather than something that sounds right, copy the Kirby protocol, because it is the one with a controlled result behind it:

Two caveats on copying it. First, 101–108 °C is hotter than a lot of home saunas are configured to run, and it is well above the roughly 80–90 °C most manufacturers cite as typical — see the vendor-stated heat-up claims we logged in our sauna kit guide and barrel sauna guide, and note that reaching a given temperature depends on your heater being sized correctly for the room volume, which is what our heater guide and kW calculator is for. Second, these were 19-to-20-year-old trained runners under supervision. A 28-minute session at 105 °C is a substantial cardiovascular load and is not a beginner's starting point.

5. Sauna vs. cold plunge after lifting: the adaptation question

People who ask about sauna timing usually ask about cold plunge timing next, and here the evidence is much clearer — and it cuts against the popular habit.

A narrative review by Petersen and Fyfe (2021), Frontiers in Sports and Active Living concluded: "current evidence suggests CWI has either nil or detrimental effects on physiological adaptations to resistance training, including muscle hypertrophy and measures of maximal strength, strength endurance, and power/RFD… Importantly, no studies have shown benefits of CWI on resistance training adaptations."

The headline study inside it is Roberts et al. (2015), 21 resistance-trained men, 12 weeks, 10 minutes at 10.1 ± 0.3 °C after each session versus low-intensity cycling as the control. Quadriceps muscle mass by MRI increased roughly 15% in the control group versus roughly 2% with cold water immersion. Leg press 1RM improved ~59% versus ~42%; knee extension 1RM ~39% versus ~21%; isometric rate of force development ~135% versus ~44%.

The same review is careful to say cold water immersion still appears to help short-term recovery — soreness, perceived fatigue, next-day performance — which is a different goal from adaptation. So the practical framing is: cold plunge when the next session matters more than the adaptation (in-season, tournament weekend, back-to-back training days), skip it in a block where you're trying to build muscle. And the caveats are real — most of these studies ran 4 to 12 weeks in relatively untrained participants at low training frequencies, and almost none included women. If you're weighing the equipment side of that decision, our cold plunge guide covers what the chiller-versus-ice choice actually costs.

Note what this does not say: there is no equivalent body of evidence that post-workout heat blunts hypertrophy. It hasn't been shown, but it also hasn't been well studied in lifters, so "sauna is safe for gains" is an absence of evidence rather than evidence of absence.

6. Safety, and who should not do this

The population evidence on regular sauna use is genuinely encouraging. In the Finnish Kuopio Ischemic Heart Disease Risk Factor Study — Laukkanen et al. (2015), JAMA Internal Medicine 175(4):542–548 — 2,315 middle-aged Finnish men were followed for a median of 20.7 years. Compared with one session per week, men having 4–7 sessions per week had an adjusted hazard ratio for sudden cardiac death of 0.37 (95% CI 0.18–0.75, p for trend = 0.005), with similar trends for coronary heart disease, cardiovascular disease and all-cause mortality. Session length mattered too: sessions over 19 minutes carried an HR of 0.48 (0.31–0.75) for sudden cardiac death versus sessions under 11 minutes.

Read at PubMed PMID 25705824 on July 18, 2026, doi:10.1001/jamainternmed.2014.8187.

That is an observational cohort, not a trial, and the journal published two letters (and the authors' reply) arguing the association may be non-causal — healthier men can sauna more often, which is the obvious confound. Only 201 of the 2,315 men were in the 4–7 sessions group, and all participants were middle-aged Finnish men, which limits how far the numbers travel. It is a strong signal, not proof, and it says nothing about workout timing.

The bottom line

If you're an endurance athlete: after, within about five minutes, ~28 minutes, ~3 times a week — that's the protocol with a controlled trial behind it, and the effects on VO₂max and time to exhaustion were large. If you lift: after is the reasonable default, but understand that nobody has properly tested pre-workout sauna in either direction, and the one study claiming a benefit can't separate its result from a retest effect. If you're deciding between adding heat or adding cold after lifting, the evidence on cold is clearer and less flattering — it helps you recover for tomorrow and appears to cost you adaptation over months.

And if you're at the stage of pricing the actual equipment, we keep a sourced, dated price database for sauna kits, barrel saunas, heaters, and cold plunges — every cell linked to the seller's live page with the date we checked it.

How we made this page

Every study cited above was located and read on July 18, 2026, and linked at the point of claim. Where we could not retrieve a primary source — Scoon et al. (2007) and Hedley et al. — we say so in the text and do not repeat those papers' numbers as verified. We flag study design problems in the studies that support our conclusion as well as the ones that don't. We are not physicians and this is not medical advice. Full methodology: /how-we-research/.