Cold Therapy - Effects & evidence
Cold after training: help or hindrance?
Last updated 30 September 2026. How we write this .
Both. Cold water after hard exercise eases soreness for a day or two, but used routinely after strength training it slows muscle growth. Endurance training gains look unaffected.
Start here Both. Cold water after hard exercise eases soreness for a day or two, but used routinely after strength training it slows muscle growth. Endurance training gains look unaffected.
By the end, you will understand Does an ice bath reduce muscle soreness? How much of the effect is the cold, and how much is belief? Can cold water after the gym slow muscle growth? Key words used in this lesson Placebo An inactive comparison given so that the effect of expectation can be separated from the effect of the intervention itself. Without one, improvement over time cannot be attributed to the treatment. Meta-analysis A statistical method for combining the results of multiple studies into a single estimate. More reliable than any one study, but bounded by the quality of what went into it. Full plain-English glossary
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It depends what you want from the next few weeks. A cold bath after a hard session usually leaves you less sore the next day, and after some kinds of exercise a little more powerful too. Used after every strength session, though, it slows the muscle growth you were training for. For runners and cyclists, the long-term effect on fitness looks neutral.
That trade-off is the whole story in miniature: feeling recovered and getting fitter are different outcomes, and cold water pushes them in different directions.
Does an ice bath reduce muscle soreness?
Yes, modestly. The best-known summary is a 2012 Cochrane review led by Chris Bleakley, which pooled 17 small trials with 366 participants. Compared with resting or doing nothing, cold-water immersion reduced delayed-onset muscle soreness, the ache that builds in the days after hard or unfamiliar exercise, at 24, 72 and 96 hours. People also rated themselves less fatigued straight afterwards.
Two details in that review are easy to miss. First, the trials were of low quality, and most did not actively check for side effects. Second, when cold water was compared with warm-water immersion or with alternating hot and cold, there was no clear difference in pain. Some of the benefit may come from simply getting into water and sitting still, not from the cold itself.
A larger 2022 meta-analysis by Emma Moore and colleagues at the University of South Australia gathered 52 studies of physically active people. After high-intensity exercise, cold water improved soreness, perceived recovery and muscular power, such as jump height, 24 hours later. It did not help strength recover after either high-intensity or eccentric exercise, the kind that loads a muscle as it lengthens, like running downhill.
How much of the effect is the cold, and how much is belief?
Quite a lot may be belief. In a 2014 study at Victoria University in Melbourne, James Broatch and colleagues had 30 men do a sprint interval session, then sit in one of three baths: cold water, lukewarm water given as a placebo recovery treatment, or plain lukewarm water. Over the next 48 hours, the placebo group recovered leg strength just as well as the cold group, and both felt more ready, less sore and more energetic than the plain warm-water group. The authors concluded that the benefits usually credited to cold water are at least partly placebo.
The popular explanation, that cold reduces inflammation in the muscle, has not held up well either. In 2017 Jonathan Peake and colleagues took muscle samples from nine active men at 2, 24 and 48 hours after a leg workout. Inflammatory cells and signalling molecules rose after exercise just as much whether the men then sat in cold water or cycled gently. Cold water was no better than light exercise at calming the muscle's inflammatory and stress responses.
Can cold water after the gym slow muscle growth?
This is where the evidence is most consistent. In a 2015 study published in the Journal of Physiology, Llion Roberts and colleagues put 21 physically active men through 12 weeks of strength training. After each session, half sat in cold water and half did easy cycling. The cycling group gained more strength and muscle. In that group the larger type II muscle fibres, the ones that produce fast, powerful force, grew by 17%, and the number of nuclei in each fibre, which support growth, rose by 26%. Neither changed significantly in the cold-water group.
A 2020 Maastricht study by Cas Fuchs and colleagues showed one likely reason. Twelve healthy men exercised both legs, then put one leg in cold water and the other in water at a neutral temperature. The cooled leg took up less protein from a recovery drink into new muscle. Over two weeks of training, muscle protein synthesis, the rate at which muscle builds new protein, ran at 1.48% a day in the cooled leg against 1.67% in the other.
Pooled results point the same way, though the size of the effect varies. A 2021 meta-analysis by Malta and colleagues in Brazil and Australia combined eight training studies and found that regular cold water had a moderate harmful effect on strength measures such as the one-repetition maximum, the heaviest weight you can lift once. A 2023 meta-analysis by Grgic, covering 10 studies and 170 people, found a smaller drag on strength gains. That effect showed up when only the trained limbs were cooled. Whole-body immersion made no clear difference.
The difference between muscle size and strength matters here. Strength depends on the nervous system and skill as well as muscle bulk, so a smaller gain in muscle size does not always show up as a smaller gain on the bar. Cold water slows progress compared with not using it. It does not wipe out a session's work.
What about runners, cyclists and team sports?
For endurance training, the worry largely disappears. Malta's meta-analysis found no effect of regular cold-water immersion on time-trial performance or maximal aerobic power, a measure of how much work your heart, lungs and muscles can sustain at full effort. There was no clear benefit either. The adaptations that make you fitter for long efforts appear to carry on regardless.
For team sports and tournaments, the balance tilts the other way. When the next match is a day or two away, feeling less sore and recovering some power by the next day may be worth more than a small slowdown in long-term muscle gain. Moore's finding of better power and perceived recovery at 24 hours fits that situation more closely than it fits someone training to build muscle.
What is still uncertain?
Most of these studies are small and mostly involve young men. In Grgic's analysis, 92% of participants were male. Nobody can be blinded to sitting in cold water, which, as Broatch showed, makes expectation hard to separate from physiology. The studies also used different water temperatures, durations and body areas, so there is no agreed answer on how long to wait after training, or whether occasional use carries the same cost as using it after every session.
Cold water is also a stress on the heart and breathing in its own right. The gasp and jump in heart rate that come with sudden immersion are covered in Cold shock, blood pressure and who should be careful. If someone becomes confused, collapses or has chest pain during or after cold exposure, call 999.
This lesson is general education about recovery research, not a training plan or medical advice. If you have a heart or circulation condition, Raynaud's, are pregnant or take regular medicines, speak to your GP before trying cold-water immersion.
Related in this classroom Related in other classrooms The studies behind this page Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise - Cochrane Database of Systematic Reviews, 2012Impact of Cold-Water Immersion Compared with Passive Recovery Following a Single Bout of Strenuous Exercise on Athletic Performance in Physically Active Participants: A Systematic Review with Meta-analysis and Meta-regression - Sports Medicine, 2022Postexercise cold water immersion benefits are not greater than the placebo effect - Medicine and Science in Sports and Exercise, 2014The effects of cold water immersion and active recovery on inflammation and cell stress responses in human skeletal muscle after resistance exercise - Journal of Physiology, 2017Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training - Journal of Physiology, 2015Postexercise cooling impairs muscle protein synthesis rates in recreational athletes - Journal of Physiology, 2020The Effects of Regular Cold-Water Immersion Use on Training-Induced Changes in Strength and Endurance Performance: A Systematic Review with Meta-Analysis - Sports Medicine, 2021Effects of post-exercise cold-water immersion on resistance training-induced gains in muscular strength: a meta-analysis - European Journal of Sport Science, 2023Further reading
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Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.