Key takeaways
Cold water immersion modestly reduces muscle soreness in the days after hard exercise
Regular plunges straight after strength training blunted gains in muscle and strength in a 12-week trial
Effects on endurance adaptations look small, so save plunges for tournaments and race weeks, not after lifting
Ice baths have gone from rugby changing rooms to back gardens and gyms. The trend is visible beyond social media: hot and cold therapies moved up the ACSM 2026 worldwide fitness trends survey, and recovery areas with cold plunges are spreading through commercial gyms. But a plunge after training has a trade-off that many fans never hear about.
What cold water does
Sitting in cold water cools skin and muscle, narrows blood vessels and reduces blood flow to the limbs. That may limit swelling and dull pain signals, which is why many people feel fresher afterwards. The same reduction in blood flow and inflammatory signalling is also the problem: some of those signals are part of how muscles adapt to training.
The recovery evidence
The Cochrane review by Bleakley and colleagues (2012) pooled 17 small trials. Compared with resting, cold water immersion reduced delayed-onset muscle soreness at 24 to 96 hours after exercise, and people reported feeling less fatigued. However, the trials were small and of low quality, and there was not enough evidence on other outcomes such as performance.
Later meta-analyses refined the picture. Machado et al., 2016 suggested the best soreness results with water at about 11–15 °C for 11–15 minutes. Moore et al., 2022 found cold water helped some markers after high-intensity exercise, but had no clear effect on the recovery of strength.
So cold plunges are a modest soreness tool, with feeling better not always the same as performing better.
The adaptation problem
The study that changed the conversation is Roberts et al., 2015 in the Journal of Physiology. Twenty-one physically active men did 12 weeks of strength training twice a week. After each session, one group sat in cold water for 10 minutes; the other did an easy active cool-down on a bike. The active recovery group gained more muscle mass and strength. In a separate acute experiment, cold water blunted the signalling proteins and satellite cell activity that drive muscle growth for up to two days after a workout.
A meta-analysis by Malta et al., 2021 pooled training studies and found that regular cold water immersion after sessions reduced gains in strength measures such as one-rep max and jump power. Fyfe and colleagues (2019) found smaller muscle fibre growth with cold water, though strength gains were similar, so not every study agrees on strength.
What about endurance and VO2max?
Here the evidence is genuinely less clear. In the Malta meta-analysis, regular cold water immersion did not clearly affect endurance outcomes such as time-trial power or maximal aerobic power. But only a handful of small studies exist, and some lab work suggests cold might even boost certain mitochondrial signals while others suggest it blunts adaptation. The honest answer: we do not know whether frequent plunges help, hurt or do nothing to long-term VO2max. If VO2max is your goal, interval training matters far more (see how to improve VO2max).
| Situation | Cold plunge? | Why |
|---|---|---|
| Between tournament games or heats | Reasonable | Short-term soreness and freshness matter more than adaptation |
| Race week or stage race | Reasonable | No time to adapt anyway; feeling fresh is the priority |
| Straight after strength training | Avoid | Blunted muscle and strength gains in trials |
| After easy endurance sessions | Optional | Little evidence of benefit or harm |
| Hot climate or heat illness risk | Useful for cooling | Rapid cooling helps in the heat (see heat training) |
Practical guidance
- Building strength or muscle? Skip the plunge after lifting, or wait several hours. If you do both, put the plunge on a different day. This matters for runners who lift too (see strength training for runners) and hybrid athletes (see VO2max for Hyrox).
- Competing repeatedly in a short time? A plunge of about 10 to 15 minutes at roughly 11–15 °C is a reasonable option between events.
- Living somewhere hot? Cold water is a good way to bring core temperature down after training in the heat, as covered in heat training and VO2max.
- Track how you respond. Sleep, resting heart rate and HRV trends tell you more about recovery than how a plunge feels.
Check your current fitness with the VO2max calculator, and find more summaries on the research page.
Safety: sudden immersion in cold water triggers a cold shock response, a gasp reflex, rapid breathing and a spike in heart rate and blood pressure, which Tipton and colleagues (2017) identify as a major cause of immersion deaths. Enter slowly, never plunge alone or in open water without supervision, and keep your head above water. If you have heart disease, high blood pressure, arrhythmia, Raynaud's or are pregnant, get medical advice first. Get out if you feel numbness spreading, confusion or uncontrollable shivering.
Frequently asked questions
Do ice baths kill gains?
Regular cold water immersion straight after strength training reduced long-term gains in muscle mass and strength in a 12-week trial, and a meta-analysis found the same pattern. Occasional use is unlikely to matter much.
Does cold water immersion help endurance training?
A meta-analysis found no clear effect of regular post-exercise cold water immersion on endurance performance gains, but the number of studies is small, so the evidence is uncertain.
How cold and how long should a cold plunge be?
Studies on soreness suggest roughly 11 to 15 °C for around 10 to 15 minutes. Colder is not necessarily better, and short, controlled first exposures reduce the risk of cold shock.
Sources
- Roberts LA, et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. J Physiol, 2015.
- Bleakley C, et al. Cold-water immersion (cryotherapy) for preventing and treating muscle soreness after exercise. Cochrane Database Syst Rev, 2012.
- Machado AF, 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 Med, 2016.
- Moore E, et al. Impact 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 Med, 2022.
- Malta ES, et al. The effects of regular cold-water immersion use on training-induced changes in strength and endurance performance: a systematic review with meta-analysis. Sports Med, 2021.
- Fyfe JJ, et al. Cold water immersion attenuates anabolic signaling and skeletal muscle fiber hypertrophy, but not strength gain, following whole-body resistance training. J Appl Physiol, 2019.
- Tipton MJ, et al. Cold water immersion: kill or cure? Exp Physiol, 2017.