Cold Plunge Benefits: What the Studies Show (and the Catch for Strength Training)

Cold plunges went from elite locker rooms to backyards and boutique studios in just a few years. The research is genuinely interesting, but it is also more nuanced than social media makes it sound. Here's what the studies say about soreness, mood, metabolism and muscle growth.

Cold water and muscle soreness

The best-known review is a 2012 Cochrane review led by Chris Bleakley. Pooling 17 small trials, it found that cold water immersion after exercise may reduce delayed-onset muscle soreness compared with resting or doing nothing. The authors flagged that most trials were small and at risk of bias, and that the best dose and safety were unclear [1].

A 2016 meta-analysis in Sports Medicine tried to pin down that dose. In the studies it reviewed, water at roughly 10 to 15 °C (50 to 59 °F) for 11 to 15 minutes produced the most consistent reductions in soreness [2]. That's a useful starting point, and warmer than many people assume. You don't need near-freezing water to see a benefit in these studies.

The "cold high": noradrenaline and dopamine

A frequently cited 2000 study by Šrámek and colleagues had volunteers sit in water of different temperatures. Head-out immersion at 14 °C (57 °F) for an hour raised plasma noradrenaline by about 530% and dopamine by about 250% [3]. That's a long immersion compared with a typical 2 to 5 minute plunge, so don't expect identical numbers. But it supports the common experience of feeling alert and energized afterward.

Cold showers and sick days

In a large Dutch trial, about 3,000 adults were randomized to finish their daily shower with 30, 60 or 90 seconds of cold water, or not at all, for 30 days. The cold-shower groups reported 29% fewer sickness absences from work, although the number of days they reported feeling ill did not change [4]. It's a self-reported outcome, but a real randomized trial.

Brown fat and metabolism

A 2021 study led by Susanna Søberg compared experienced winter swimmers who used both sauna and cold water with non-swimmers. The winter swimmers showed differences in how their bodies produced heat in response to cold, including brown fat activity [5]. This is a small observational study of a very specific group, so it shouldn't be read as "cold plunging burns fat." It's one reason the "end on cold" approach to contrast therapy has become popular.

The catch: cold plunges and muscle growth

This is the part many cold plunge sellers skip. In a 2015 study in The Journal of Physiology, Llion Roberts and colleagues had men do strength training twice a week for 12 weeks, followed by either 10 minutes of cold water immersion or active recovery. The cold water group gained less muscle mass and strength over the 12 weeks, and lab measures showed blunted muscle-building signals [6].

The practical takeaway isn't "avoid cold." It's timing. If muscle gain is a priority, many coaches suggest saving the plunge for rest days, before training, or several hours after lifting. For soreness relief between games or hard endurance days, plunging soon after can make more sense.

What this means for gyms and studios

Cold plunge is one of the most "shareable" amenities a studio can offer, and it gives members a reason to linger. Posting simple guidance by the tub (start in the 50s °F, 2 to 5 minutes, and the timing note for lifters) shows members you know the science and keeps them safe. A plunge paired with a sauna makes a natural contrast circuit. See our contrast therapy guide.

Safety basics

• Cold shock can spike heart rate and blood pressure. Talk to your doctor first if you have heart disease, high blood pressure or Raynaud's.
• Never plunge alone or after drinking alcohol.
• Enter slowly and control your breathing. Avoid forceful breath-holding in water.
• Get out if you feel numb, confused or start shivering hard.

Ready to compare tubs and chillers? Read our cold plunge buying guide.

References

1. Bleakley C, McDonough S, Gardner E, Baxter GD, Hopkins JT, Davison GW. Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. Cochrane Database of Systematic Reviews. 2012;(2):CD008262. doi:10.1002/14651858.CD008262.pub2
2. Machado AF, Ferreira PH, Micheletti JK, et al. Can water temperature and immersion time influence the effect of cold water immersion on muscle soreness? A systematic review and meta-analysis. Sports Medicine. 2016;46(4):503-514. Find on PubMed
3. Šrámek P, Šimečková M, Janský L, Šavlíková J, Vybíral S. Human physiological responses to immersion into water of different temperatures. European Journal of Applied Physiology. 2000;81(5):436-442. Find on PubMed
4. Buijze GA, Sierevelt IN, van der Heijden BCJM, Dijkgraaf MG, Frings-Dresen MHW. The effect of cold showering on health and work: a randomized controlled trial. PLoS ONE. 2016;11(9):e0161749. doi:10.1371/journal.pone.0161749
5. Søberg S, Löfgren J, Philipsen FE, et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men. Cell Reports Medicine. 2021;2(10):100408. PubMed
6. Roberts LA, Raastad T, Markworth JF, 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;593(18):4285-4301. Find on PubMed

The information on this site is for general education and is not medical advice. Talk with your doctor before starting heat, cold, light, pressure, float, PEMF or vibration therapy, especially if you are pregnant or have a medical condition. We may earn a commission when you buy through our links. Learn more.