Cold water after lifting feels like discipline. For muscle growth, the timing works against you. The plunge is not the problem. Putting it right after the session you wanted to grow from is.
Sauna is a different question with a thinner answer. Here is what the research supports for each, and where it runs out.
What Cold Water Does After A Lift
Three studies changed how people think about this. In the first, 21 men trained for 12 weeks. Half sat in cold water for 10 minutes after every session. The other half did an easy cooldown. Strength and muscle mass went up more in the group that skipped the cold.
A second study ran 7 weeks with 15 minutes at 10°C after each workout. Maximal strength improved either way. Muscle fiber growth did not. It was blunted in the cold group.
A third looked at why. One leg went into 8°C water after training and the other into neutral-temperature water. The cooled leg built muscle protein more slowly, and it stayed that way across two weeks of training.
Those are small studies, all in young men. But the direction held up. A 2026 review that pooled 15 separate meta-analyses reached the same conclusion: cold water immersion after exercise impaired strength and muscle size gains.
What Cold Water Is Actually Good For
The same review is the best argument for the plunge. Cold water reduced muscle soreness for up to four days. It helped power and jump performance recover a day or two after hard work. The protocols that worked best were 10 to 15 minutes in water between 5 and 15°C.
So cold is a recovery tool, not a growth tool. That is a real use. A tournament weekend. Two sessions in one day. A stretch of the season where being fresh tomorrow matters more than being bigger in three months. The reviewers rated the overall evidence as low certainty, so hold all of this loosely.
| If the goal is | Cold right after | Sauna right after |
|---|---|---|
| Muscle size | Works against you | No good evidence either way |
| Maximal strength | Mixed. The pooled review found impaired gains | No good evidence either way |
| Less soreness tomorrow | Helps, for up to four days | Uncertain |
| Endurance | No lasting benefit to adaptation | May help running, mostly shown in the heat |
So When Do You Plunge?
Be careful with anyone who gives you an exact number of hours. The studies tested cold straight after lifting. None of them tells you how long a gap makes it harmless.
The conservative read is simple. Keep cold away from the sessions you want to grow from. Use it on rest days, on days you only do easy cardio, or first thing in the morning when the lift is hours away. If you love the plunge and you are trying to add muscle, that is the trade to make.
Sauna Is A Different Story, And A Thinner One
Heat does not have the same strike against it. It also does not have much proof behind it. A 2025 systematic review of 14 trials on sauna and hot water after exercise could not draw firm conclusions. The longer studies suggested heat after training may improve running performance, mostly in hot conditions. It did nothing for cycling performance or VO2 max.
I could not find a trial showing that a sauna after lifting blunts muscle growth the way cold does. I also could not find one showing it helps. Anyone promising a number is ahead of the data.
The stronger sauna evidence is about the heart, not the gym. In a Finnish study that followed 2,315 middle-aged men for about 20 years, the ones who used a sauna four to seven times a week had lower rates of fatal heart disease and death from any cause than the ones who went once. That is an observational study. It shows an association, not proof that the sauna did it.
How To Use Both Without Turning This Into A Protocol
- Decide what the block is for. Building muscle and feeling fresh tomorrow are different goals. Cold serves the second one.
- Put cold where it cannot interfere. Rest days and easy days, not the hour after squats.
- Treat sauna as its own habit. After a lift is fine if you like it. Drink water, and do not count it as training.
- Watch your own recovery. If sleep and next-day strength hold, the routine is working for you.
Heat and cold both stress the heart and blood vessels. If you have a heart condition, low blood pressure, or you are pregnant, ask a clinician before making either a habit.
What I Built Mallet To Do With This
The research tells you about averages in small groups of young men. It does not tell you what a plunge does to your Thursday. Mallet logs sauna and cold sessions with a timer, right next to your lifting, sleep, and recovery. After a few weeks you can look back at where the sessions fell against your lifts, instead of guessing.
Log the plunge and the sauna the same way you log a set. Mallet puts heat and cold next to training and recovery, so timing becomes something you can see instead of something you argue about. Get early access →
This Week
Look at your last seven days. Count how many cold sessions landed within an hour of lifting. If muscle is the goal, move those to rest days and change nothing else. Recovery is only half of the picture. The other half is whether the training is worth recovering from, which is where the body recomp protocol and your protein target come in.
Selected References
- Roberts LA, et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. The Journal of Physiology. 2015.
- Fyfe JJ, et al. Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. Journal of Applied Physiology. 2019.
- Fuchs CJ, et al. Postexercise cooling impairs muscle protein synthesis rates in recreational athletes. The Journal of Physiology. 2020.
- Berjisian E, et al. Strategic application of post-exercise cold-water immersion to enhance performance recovery and adaptation: an umbrella review of 15 published systematic reviews with meta-analysis. Sports Medicine - Open. 2026.
- Ahokas EK, et al. Effects of post-exercise heat exposure on acute recovery and training-induced performance adaptations: a systematic review. Sports Medicine - Open. 2025.
- Laukkanen T, et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine. 2015.
This article is for education, not medical advice. Heat and cold exposure carry real risks for some people. Talk to a clinician first if you have a heart condition, blood pressure problems, or are pregnant.