Using a sauna after strength training is often promoted as a way to improve recovery. However, could post-workout heat also help you build more muscle?
A new systematic review and meta-analysis looked at the available research on heat therapy used shortly after resistance training. The findings suggest there might be a small benefit for muscle growth, but the evidence is not yet strong enough to make post-workout heat an essential part of your training routine.
Why Might Heat Help Muscle Growth?
Resistance training gives your muscles a reason to adapt. During the hours and days that follow, your body repairs the trained muscle tissue and, under the right conditions, builds it back stronger and larger.
Heat exposure may influence some of the processes involved in this response. For example, increasing muscle temperature can affect blood flow and activate heat-related proteins that help cells cope with stress.
This has led researchers to investigate whether applying heat after resistance training could enhance the normal muscle-building response.
However, a biological explanation does not automatically mean something produces meaningful results in the gym. Long-term training studies are needed to find out whether the proposed mechanisms actually lead to greater muscle growth or strength.
What Did the Researchers Investigate?
The new paper combined the results of studies comparing resistance training with and without post-exercise heat therapy.
To be included, studies had to:
Six interventions involving a total of 125 participants met the inclusion criteria.
That is an important detail. Although combining studies can provide a clearer picture than looking at one experiment alone, the overall evidence base was still relatively small.
Did Heat Therapy Improve Muscle Growth?
The analysis found some evidence of a small advantage for heat therapy.
The estimated effect was small, and the researchers calculated an 89.7% probability that the true effect favoured post-training heat. In everyday terms, the results lean towards heat therapy being helpful for muscle growth.
However, there was still considerable uncertainty. The range of plausible results included the possibility of no meaningful benefit.
Therefore, this study does not show that sitting in a sauna after training will definitely build more muscle. Instead, it suggests there may be a small positive effect worth investigating in larger and better-controlled studies.
Post-workout heat therapy may provide a small muscle-growth benefit, but the current evidence remains uncertain.
What About Strength?
The results were less encouraging for strength.
Overall, applying heat after resistance training did not produce a meaningful improvement in strength compared with resistance training alone.
This distinction matters because muscle size and strength are related but not identical. A person can become stronger through improvements in technique, coordination and the nervous system, as well as through increases in muscle size.
Based on the current evidence, post-workout heat should not be viewed as a reliable way to increase strength.
How Reliable Are These Findings?
The researchers rated the included studies as generally fair-to-poor in methodological quality. There were also only six eligible interventions and 125 participants in total.
As a result, the apparent muscle-building benefit could change as more research becomes available.
This is why the findings should be described as promising rather than conclusive. The review gives researchers a reason to continue investigating post-exercise heat, but it does not yet provide a strong basis for changing everyone’s training routine.
Should You Use a Sauna After Strength Training?
If you already enjoy using a sauna or another form of heat therapy after training, the findings provide an interesting potential benefit. However, muscle growth shouldn't be the main reason you use it.
Heat exposure may add extra physical stress after an already demanding workout. It can also increase sweating and fluid loss, so hydration and personal tolerance need to be considered. Longer or hotter sessions aren't necessarily better.
More importantly, heat therapy should sit well below the established foundations of muscle growth:
If those foundations are not in place, adding a sauna session is unlikely to make a noticeable difference.
A Practical Takeaway
Post-training heat therapy may provide a small additional benefit for muscle growth, but the evidence remains uncertain. It does not appear to produce a meaningful improvement in strength.
For now, heat therapy is best viewed as an optional addition rather than a muscle-building requirement. If you enjoy it, tolerate it well and can use it without compromising your hydration or recovery, there may be no need to avoid it. However, you don't need to start taking hot baths or sitting in a sauna because you are worried about missing out on muscle growth.
Your training, nutrition and recovery habits will continue to do most of the heavy lifting.
Research Reviewed
This article is based on the following systematic review and meta-analysis, published in Sport Sciences for Health in August 2026:
- 1Hopper, A., Coleman, M., Piñero, A., et al. (2026). Feeling the heat: a systematic review with meta-analysis on the effects of post-resistance training heat therapy on muscular adaptations. Sport Sciences for Health, 22(3), 323. https://doi.org/10.1007/s11332-026-01903-6
Frequently Asked Questions About Sauna After Strength Training
Possibly, but the effect appears to be small and remains uncertain. The latest review found some evidence favouring post-training heat therapy, although the limited number and quality of the available studies prevent firm conclusions.
Current evidence does not show a meaningful strength benefit from applying heat after resistance training.
The current research does not establish one ideal temperature or duration for increasing muscle growth. Sauna use should therefore be based on personal tolerance, hydration and general safety rather than the assumption that longer or hotter sessions will produce better results.
