Cold water can ease next-day soreness after hard exercise, but part of that may be placebo. Evidence on mood and immunity is thin, muscle growth may suffer slightly, and the sudden cold carries real heart and drowning risks.
By The Savvy Rabbits Staff ·
✓Checked twice. Fact-checked against the original sources and approved by an editor. About our standards
Partly, and less than the hype suggests. Cold water seems to ease soreness and help people feel recovered the day after hard exercise, though some of that may be expectation. Claims about mood and immunity rest on thin evidence, plunging right after strength training may modestly limit muscle growth, and the sudden cold carries real risks for the heart and breathing.
Researchers at the University of Portsmouth described "an explosion" in people trying cold immersion, from home ice baths to open-water dips, for claimed mental and physical benefits. Those claims include faster recovery, better mood, less stress and lower inflammation.
Do ice baths help with recovery after exercise?
For soreness, there is real support. A 2022 review in Sports Medicine pooled 52 studies comparing cold water with passive recovery. Twenty-four hours after high-intensity exercise, cold water improved muscle soreness, perceived recovery and muscular power. It had no significant effect on recovering strength.
Comparisons like these have a built-in weakness. People know when they are sitting in cold water, so belief can shape how they rate their soreness.
Could it be mostly placebo?
Two trials tested that directly, and both point the same way.
In a 2014 study in Medicine & Science in Sports & Exercise, 30 men did four 30-second sprints, then one of three 15-minute recoveries: cold water at about 50°F (10.3°C), lukewarm water given as a placebo, or lukewarm water with no placebo. Over 48 hours, the placebo matched cold water on leg strength and on ratings of readiness, pain and vigor, and both beat the plain lukewarm control. The authors concluded the assumed physical benefits are "at least partly placebo related."
A 2018 marathon study of 31 trained male runners compared cold water, whole-body cryotherapy and a placebo. Apart from one blood marker of inflammation, neither cold method beat placebo on blood markers of inflammation or muscle damage. In their conclusion, the authors used "cryotherapy" to cover both cold methods. They found it no more effective than placebo for functional recovery or perceived training stress, and suggested belief may be largely responsible for the benefits. The study's abstract gives no separate cold-water result on those two measures.
These were small studies in men. Women are poorly represented in this research. In a 2025 trial in PLOS One, 30 women did a muscle-damaging jumping workout and then had cold water, hot water or rest. Neither kind of water improved recovery over 72 hours compared with rest. With 10 women per group, that is an early finding, not a final answer.
What about mood, stress and inflammation?
The evidence here is thinner than the marketing. A 2025 review in PLOS One looked at 11 randomized trials in healthy adults, with 3,177 participants. Of those, 3,018 came from a single cold-shower study, and every other trial enrolled only men.
The results:
Stress: Lower 12 hours after immersion, but not immediately, or at 1, 24 or 48 hours.
Inflammation: Higher immediately and one hour afterward, the opposite of the popular claim. A brief rise says little about long-term effects.
Mood: No significant difference, in one study of 20 men.
Sleep: Better self-rated sleep quality in that same study.
Immune function: No significant change in the pooled data, immediately or one hour afterward. In the cold-shower study, people had 29% less sickness absence from work, yet the number of days they reported being ill did not differ.
The authors called the evidence on immunity and mood inconclusive, and said stronger research is needed to establish safety.
Can a cold plunge hurt muscle growth?
It may, modestly. A 2024 meta-analysis in the European Journal of Sport Science pooled eight studies of strength training with and without cold water. There was some evidence of larger muscle growth with training alone, with an effect size of 0.36 against 0.14 with cold water added. The authors concluded that immersion right after lifting "may modestly attenuate" growth.
Participants were mostly young men, most studies lasted four to eight weeks, and the authors rated study quality as fair to poor overall. The research covered plunging within about 15 minutes of training, so it cannot say what happens with a plunge hours later.
What are the risks?
The most dangerous reaction is cold shock. A 2022 editorial in the British Journal of Sports Medicine describes gasping, hyperventilation, a release of stress hormones, high blood pressure and irregular heartbeats. It peaks in water between 50 and 59°F (10 to 15°C), during the first 30 seconds. Losing control of breathing can lead to drowning. Irregular heartbeats are especially common when the face goes under or a person holds their breath.
The editorial's screening list flags these conditions for medical review, among others:
high blood pressure, heart rhythm problems, or structural or ischemic heart disease
Anyone with a health condition, or taking regular medication, should talk to a doctor first and keep taking any prescribed medication as directed. For those who go ahead, the editorial advises entering gradually rather than jumping or diving in, keeping immersions under 10 minutes in colder water, and not judging time by how cold it feels. It links alcohol and recreational drugs to deaths in cold water, and advises against driving for about 30 minutes afterward, since the body keeps cooling. Having someone nearby is a simple extra precaution.
This article is for general education only and is not medical advice. Talk to a doctor or other qualified health professional before changing your diet, supplements, medication, or treatment.
Sources
Outside, "5 Wellness Trends We'd Like to See Go Away" (Calin Van Paris, November 4, 2026): https://www.outsideonline.com/health/wellness/wellness-trends-2026-we-are-over/
PubMed, "Impact of Cold-Water Immersion Compared with Passive Recovery Following a Single Bout of Strenuous Exercise on Athletic Performance in Physically Active Participants" (Moore et al., Sports Med 2022): https://pubmed.ncbi.nlm.nih.gov/35157264/
PubMed, "Postexercise cold water immersion benefits are not greater than the placebo effect" (Broatch, Petersen, Bishop, Med Sci Sports Exerc 2014): https://pubmed.ncbi.nlm.nih.gov/24674975/
PubMed, "Recovery following a marathon: a comparison of cold water immersion, whole body cryotherapy and a placebo control" (Wilson et al., Eur J Appl Physiol 2018): https://pubmed.ncbi.nlm.nih.gov/29127510/
PLOS One via PMC, "No acceleration of recovery from exercise-induced muscle damage after cold or hot water immersion in women: A randomised controlled trial" (Wellauer et al., 2025): https://pmc.ncbi.nlm.nih.gov/articles/PMC12057877/
PLOS One via PMC, "Effects of cold-water immersion on health and wellbeing: A systematic review and meta-analysis" (Cain et al., 2025): https://pmc.ncbi.nlm.nih.gov/articles/PMC11778651/
European Journal of Sport Science via PMC, "Throwing cold water on muscle growth" (Piñero et al., 2024): https://pmc.ncbi.nlm.nih.gov/articles/PMC11235606/
University of Portsmouth, accepted manuscript of "Cold water therapies: minimising risks" (Tipton et al., Br J Sports Med 2022): https://pure.port.ac.uk/ws/portalfiles/portal/58597102/Cold_water_therapies_minimising_risks.pdf
National Institute of Arthritis and Musculoskeletal and Skin Diseases, "Raynaud's Phenomenon": https://www.niams.nih.gov/health-topics/raynauds-phenomenon
UVM Health, "To Cold Plunge or Not to Cold Plunge": https://www.uvmhealth.org/the-beat/heart-vascular/to-cold-plunge-or-not-to-cold-plunge
Our take
This take is opinion, not professional advice.
The Savvy Rabbits Staff
Our editors' take
We would keep two questions apart. Does a plunge make you feel better tomorrow? Quite possibly. Does the cold itself do the work? That is much less settled. Broatch and colleagues showed in 2014 that lukewarm water presented as a placebo matched cold water on strength recovery, and that result is hard to wave away. It is also one small study of 30 men after one sprint session. We would push back on anyone selling certainty in either direction, including those who now say they would like to see cold plunges for everyone go away. Feeling recovered has some value, even if belief supplies part of it. What we would not shrug at is the first 30 seconds, when a gasp you cannot control happens with your body in water.
