What Happens to Your Muscles When You Add Heat After Training

If you have your training, diet, and sleep locked down, you're looking for any potential benefit in your workout recovery, even if it's marginal. The more efficiently you can recover, the more volume, intensity, and frequency you can add to your training.

At this stage, many turn to supplements, the emerging peptide market, or recovery modalities like red light therapy to squeeze out every possible advantage. But a new meta-analysis looked at the link between muscle recovery, strength gains, and a tool that might be sitting in your gym right now.

Researchers searched multiple scientific databases and found 6 studies that tested what happens when people apply heat (sauna, hot water immersion, or heating pads) shortly after resistance training, compared to just resting after training. They pooled the results using a statistical method called Bayesian meta-analysis.

There was a small but meaningful signal favoring heat therapy. By their estimation, researchers believe that there is roughly a 90% probability that heat therapy provides some benefit for muscle growth compared to training alone.

Heat therapy showed essentially no advantage over regular recovery for strength gains. Both groups got stronger, but the heat therapy group wasn't meaningfully ahead. The results were also inconsistent across studies.

Given these results, it might be worth hopping in your gym's sauna for 10 minutes or so post-workout. While it won't provide dramatic results, there seems to be a small boost toward muscle hypertrophy. The proposed mechanism is that heat increases blood flow, which may improve nutrient delivery to muscles and activate growth-related proteins (i.e. heat shock proteins).

That said, keep expectations realistic. The studies included were not considered to be the greatest quality, and only 6 qualified for analysis. Heat modalities, temperatures, and durations varied wildly across studies, and most research was conducted on young adults focusing primarily on lower body muscles. What we can say with reasonable confidence is that post-workout heat therapy appears to be a better option than ice baths if muscle growth is your goal, since cold therapy after training has actually been shown to blunt muscle growth. If your gym has a sauna or hot tub, it costs you nothing extra to use it. At this stage of the game, anything that gives you a slight edge is worth doing.

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This story was originally published June 16, 2026 at 4:24 PM.