This conversation makes a deceptively simple argument: sauna use after resistance training may support muscle recovery and growth, while cold exposure immediately after training actively suppresses it. The hypertrophy suppression from cold plunging proximal to a training sessionâsomewhere in the range of 20 to 30 percentâis one of the more robust findings in recovery science right now. And yet people are still running from the weight room to the ice bath and wondering why they're spinning their wheels.
The sauna side of the equation is murkier, which I appreciate that they acknowledge up front. The longitudinal data on sauna and hypertrophy specifically is thin. What we have is a collection of Finnish epidemiological dataâ40 to 50 percent lower all-cause mortality risk for people using the sauna four or more times per weekâand a plausible mechanistic story involving heat shock proteins. That's not a direct line from sauna to bigger biceps. But it's not nothing, either.
The heat shock protein mechanism is worth dwelling on. When heat hits your body, your cells produce these molecular chaperones that help proteins fold correctly and reach their intended destinations. In the context of muscle recovery, you've just created a tremendous amount of mechanical stressâtorn fibers, disrupted protein structures, inflammatory signaling cascades. Your body is running a complex repair operation. Heat shock proteins are part of the quality control system for that operation. More of them, potentially, means more efficient repair.
We've seen this theme across the research repeatedly. Heat is a cellular stressor that, in the right dose, improves the fidelity of your body's internal processes. The Rhonda Patrick work on heat shock proteins and their role in clearing misfolded proteinsâthe same ones linked to neurodegenerative diseaseâfollows the same underlying logic. Sauna doesn't just relax you. It activates repair systems that your body runs too quietly when life is comfortable.
The honest caveat in this conversation is important: the Finnish mortality data is correlational, and health-conscious people do health-conscious things. Sauna attendance in certain cultures is itself a marker of the kind of person who exercises, sleeps well, and eats deliberately. Confounding is real. We shouldn't overstate the evidence for sauna as a direct muscle-growth driver.
What's more solid is the cold exposure side. The research on cold plunging post-training is cleaner. Cold constricts blood flow, blunts the inflammatory signaling that initiates hypertrophy, and impairs muscle protein synthesis in a measurable way. If you're training for performance or muscle development, cold immediately post-training is working against you. That's not really debated at this point.
The recommendation here is clear and I agree with it. Finish your resistance training session. Let your body cool slightly. Then use the saunaâ10 to 20 minutes at around 170 degrees Fahrenheit. Bring your post-workout nutrition. Hydrate aggressively. Don't cold plunge until several hours later, or save it for non-training days entirely if muscle growth is the priority.
Here's what doesn't get said often enough: the sequencing of thermal stressors matters as much as the stressors themselves. Heat and cold are not just oppositesâthey trigger different cellular programs. Heat is anabolic-adjacent. It supports protein synthesis, promotes blood flow, activates repair cascades. Cold is catabolic-adjacent in the acute post-training window. It blunts exactly the inflammatory response your muscles need to initiate growth.
This means contrast therapyâwhich we care deeply about at Contrast Collectiveâneeds to be prescribed intelligently. A cold-hot-cold protocol on a rest day is a different conversation than a cold plunge immediately after squats. Context is everything. The tool is only as good as the timing. Understanding that distinction is the difference between a recovery ritual that builds you up and one that quietly holds you back.