Sport and fitness trends. 12 minute read.
Ice baths and saunas after training: what each one does to your gains
By the PocketPhysio editorial team. Published 2026-10-01.
The question this page answers, and the one it does not
If you want to know whether to put heat or ice on muscles that are already sore, that is a different question and it is answered on our page about muscle soreness after exercise or injury. Nothing here changes it.
This page takes the other half, the one the soreness research never touches. Does cooling after a hard strength session cost you the adaptation you trained for? That is why a cold plunge after a workout can be described as useful and as counterproductive in the same breath, by people who are both right.
The short version: cold water straight after lifting makes that session slightly less productive for muscle size, and it makes you feel readier the next day. Pick according to which of those you need this week.
What cooling straight after lifting does to muscle growth
The best summary available is a 2024 systematic review with meta-analysis in the European Journal of Sport Science. It pooled 8 interventions with 116 participants between them, in programs of 4 to 12 weeks, each comparing resistance training against the same training followed by cold water immersion (Pinero and colleagues, 2024).
Training without the cold came out ahead. The pooled comparative standardized mean difference was -0.22 (95% credible interval -0.47 to 0.04), and the authors put the probability that the true difference sits below zero at 0.957 and the probability of at least a small reduction at 0.834. Looked at separately, resistance training alone produced a hypertrophy effect of 0.36 (0.10 to 0.61) and resistance training plus cold water produced 0.14 (-0.08 to 0.36).
Four things keep this a modest finding rather than a dramatic one:
- Every trial applied the cold within 15 minutes of the last set, and the authors state that the result applies only to that timing.
- The immersions were 10 to 20 minutes at 10 to 15 C (50 to 59 F), and 6 of the 8 used 10 C (50 F). This is a cold bath, not a cold shower.
- Only 1 of the 8 studies included any female participants, and none included adolescents or older adults.
- On the review's quality tool the mean score was 9.8 out of 20, with no study rated good, 3 rated fair and 5 rated poor.
One more line matters for the phrase people search. This review measured muscle size, and strength was not its outcome. Its authors flag a study in which cold water reduced gains in size but not in strength within the same cohort, so a blanket claim about gains goes further than what was tested.
Why a cold plunge still earns its place
This is a different question with a different literature, and here cold water does well. A 2022 systematic review in Sports Medicine pooled 52 randomized trials of cold water immersion against passive rest after one strenuous session. Twenty four hours after high-intensity exercise, muscular power favored the cold group at a standardized mean difference of 0.22 (95% confidence interval 0.004 to 0.43) from 17 studies and 278 participants, and perceived recovery favored it at 0.66 (0.29 to 1.03) from 5 studies and 79 participants (Moore and colleagues, 2022).
Keep an eye on those denominators. The perceived recovery estimate rests on 79 people across 5 trials, which is a lead rather than a settled number. Creatine kinase, a blood marker of muscle damage, was lower at -0.85 (-1.61 to -0.08) in 105 participants from 5 studies. Strength at 24 hours showed nothing, at 0.12 (-0.38 to 0.62) from 3 studies and 62 participants, and an analysis that small says little in either direction. The review graded the certainty of all four of these estimates as moderate, so none of them is a closed question.
Now put the two bodies of evidence next to each other. A weekend tournament, two sessions in a day, the middle of a training camp, a second race tomorrow: in all of those, how you perform tomorrow is worth more than the adaptation from one session, and the cold plunge is a defensible tool. In a hypertrophy block with nothing to perform at, there is no reason to pay even a small tax.
What is known about heat after training
Less than the sauna conversation suggests. A 2025 systematic review in Sports Medicine Open found 14 studies with 194 participants in total, 9 of them on acute recovery and 5 on training adaptation. The authors could not combine them at all, because the studies differed in design, in heating protocol, in exercise type, in outcome measured and in recovery time, and they concluded that definitive conclusions about post-exercise heat are not possible from what exists (Ahokas and colleagues, 2025). That review was supported in part by the Finnish Sauna Society, and its conclusion runs against that interest.
The detail behind that conclusion is worth having. Only 3 of the 14 studies included any female participants. On the Cochrane risk of bias tool, 3 studies were rated at high risk of bias and the other 11 raised some concerns, so not one was rated low risk, and the authors put the overall quality of the evidence at low to moderate.
Their own closing request is for work on repeated post-exercise heating and adaptations in strength and power. Among the acute studies, 5 measured maximal isometric force after resistance-type training: 1 found heat reduced the drop in force and the other 4 found no difference. On the endurance side, one study of young swimmers and triathletes found all-out swimming was slower the morning after a post-exercise sauna than after a placebo.
So heat after training is an open question, not a quiet benefit. It is a thin basis for a weekly habit.
Should you use an ice bath or a sauna after training?
The rule is simple enough to keep in your head. If the point of this session was muscle size, do not get into cold water in the 15 minutes after it. If the point is to be able to go again tomorrow, cold water is reasonable. If the point is that you like it, that is allowed too, and nobody takes the muscle back off you for enjoying a sauna.
There is one more option the 2024 review leaves open by saying what it does not cover. Its finding is specific to immersion within 15 minutes of finishing, and the authors note that people often use cold water several hours after training or only on some days, which their data cannot speak to. Moving the plunge away from the session is the compromise people reach for, and nobody has tested it. The review says only that its finding applies to cooling within 15 minutes of the last set; it does not say that cooling later costs nothing.
Whatever you choose, it sits on top of the training, not in place of it. No tub and no hot room has ever been shown to add what a progressive program adds.
Where the real risk sits, at both ends of the thermometer
Both ends of the thermometer load the circulation, and that is the part of this subject to be careful about, not what happens to your gains. The British Heart Foundation describes entering very cold water as a cold shock that causes a faster heart rate, higher blood pressure and shortness of breath, and says cold water can lead to hypothermia and raise stress hormone levels, increasing the risk of abnormal heart rhythms and possibly cardiac arrest.
It advises checking with your doctor or nurse specialist about how to exercise safely in water, and reports guidance from the Association of Chartered Physiotherapists in Cardiac Rehabilitation that 26 to 33 C (79 to 91 F) is the safest water temperature range for people with heart conditions (British Heart Foundation, 2023). Every ice bath protocol in the research above is far colder than the bottom of that range. So if you have a heart condition, the conversation to have is whether cold water is right for you at all, rather than only how long to stay in it. The same page advises going with a friend or as part of a group rather than swimming alone, which transfers straight to a tub in a garden.
Blood pressure that is not under control is a separate case, and this page is deliberately stricter than the usual exercise advice: leave the cold water until it is controlled, rather than only asking first. Before starting exercise the standard advice is to check with your doctor, because exercise is worth that conversation. A cold plunge is not: it adds a sharp rise in blood pressure on top of one that is already high, and waiting costs you nothing.
The hot end has its own list. In the systematic review of 40 sauna studies with 3,855 participants, the harms reported inside the trials were mild to moderate heat discomfort or intolerance in 4 of those studies, low blood pressure with light-headedness in 1, airway irritation in 2, and transient leg pain and claustrophobia in 1 each. Nothing in them needed emergency medical services, and the authors ask for better quality data on how often and how badly side effects happen. The same review points at the wider medical literature, where saunas appear alongside burns, heart muscle ischemia especially in people with unstable coronary artery disease, fainting and falls, heatstroke, muscle breakdown and death, and cites retrospective population studies of frequent sauna users that reported annual sauna death rates of 0.06 per 100,000 inhabitants in Sweden and 2 per 100,000 in Finland, with half or more of those deaths involving alcohol (Hussain and Cohen, 2018).
Four practical rules follow from that. With a heart condition or high blood pressure, check with your doctor before you start the heat end, and leave the cold end until your blood pressure is under control. Leave alcohol out of both the sauna and the tub, since it is the factor those population figures keep naming. Do not use either one alone, because every serious event on that list needs somebody there to notice it. And get out when you have had enough rather than when a timer or a friend says so.
If you are pregnant, the heat end has its own answer and it is a cautious one. The NHS says there is little research on saunas, jacuzzis, hot tubs or steam rooms in pregnancy, and that you may choose to avoid them because of the risks of overheating, dehydration and fainting.
A significant rise in your core temperature could be harmful, it says, particularly in the first 12 weeks, and overheating sends blood to the skin and away from organs including the brain, which is what makes you feel faint. Its advice is that you may want to avoid situations where you could get too hot, that a hydrotherapy pool should not be above 35 C (95 F), and that it is best to avoid hot tubs, some of which reach 40 C (104 F) (NHS advice on saunas and jacuzzis in pregnancy). The cold end has not been studied in pregnancy at all. Ask your own midwife or maternity team before using either end of the thermometer, and treat both as optional until you have.
The cold has a hazard that has nothing to do with your gains. The British Heart Foundation names hypothermia among the things cold water can lead to (British Heart Foundation, 2023), and the NHS signs in an adult are shivering, pale, cold, dry skin, lips that may turn blue or grey, slurred speech, slow breathing, tiredness or confusion. If you think somebody has hypothermia, the NHS advice is to go to an emergency department or call emergency services, and not to drive yourself.
Get them somewhere sheltered. Take off any wet clothing. Wrap them in a blanket, a sleeping bag or a dry towel, give them a warm drink that is not alcoholic and something sugary to eat, and keep them awake by talking to them.
Three of its instructions matter on a page like this one: do not use a hot bath, a hot water bottle or a heat lamp to warm somebody up, do not rub their arms, legs, hands or feet, and do not give them alcohol to drink (NHS Hypothermia). The first of those rules the sauna out as a rewarming device, which is exactly the habit a page about both ends of the thermometer tends to produce.
Heat has the mirror version. Heat exhaustion is the warning stage, and the NHS lists it as tiredness, dizziness, headache, feeling sick or being sick, heavy sweating with skin that goes pale and clammy, which is harder to see on brown or black skin, cramps in the arms, legs or stomach, a high temperature, being very thirsty or feeling irritable. Moving to a cool place, taking off extra clothing, drinking water and cooling the skin by spraying or sponging it and fanning usually settles it within 30 minutes. Heatstroke is the emergency, and its signs are a very high temperature, hot skin that is not sweating and may look red, again harder to see on brown or black skin, a fast heartbeat, fast breathing or shortness of breath, confusion or clumsiness, a fit, or loss of consciousness, along with still being unwell after 30 minutes of resting, cooling and drinking (NHS Heat exhaustion and heatstroke). Both are in the warning list below, at the speed each one sets.
If chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack. If it eases quickly and none of these happen, get medical advice the same day, and do not exercise again until you have been checked. If you faint while exercising, call emergency services, even if you feel fine again quickly. That line is written for the gym.
For the sauna and the tub, use the rest of the NHS list: if somebody faints, call emergency services if they are not breathing, cannot be woken within 1 minute, have not fully recovered or have trouble speaking or moving, have chest pain or a pounding, fluttering or irregular heartbeat, have hurt themselves, are shaking or jerking, or fainted while lying down (NHS Fainting). That last one is worth reading twice on a page about saunas, where lying on a bench is the normal position. Fainting in water is its own reason not to get in alone.
When to see a physio (physical therapist)
Book when recovery has become the problem you are trying to solve with equipment. If you need a plunge or a sauna to get through your training week, the week is usually the thing that needs changing, and that conversation is about how much you are doing, how fast you added it and how well you are sleeping, not about temperature.
Come in sooner if a muscle or tendon has been grumbling for more than a couple of weeks, if the same spot hurts at the same point in every session, or if something swells after training. Bring your training log, since the fortnight before a complaint appeared explains more than the session it appeared in. Anything in the warning list below outranks all of this, at whatever speed its own line sets.
See a doctor promptly if
- Emergency: if chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack. If it eases quickly and none of these happen, get medical advice the same day, and do not exercise again until you have been checked.
- Emergency: somebody faints in a sauna or a hot room, in cold water or as they get out of it. Get them out, lie them down and stay with them. Call emergency services if they are not breathing, cannot be woken within 1 minute, have not fully recovered or have trouble speaking or moving, have chest pain or a pounding, fluttering or irregular heartbeat, have hurt themselves, are shaking or jerking, or fainted while lying down. Call emergency services as well for anyone who faints while exercising, even if they feel fine again quickly.
- Emergency: in or after a sauna or a hot room, a very high temperature, hot skin that is not sweating and may look red (harder to see on brown or black skin), a fast heartbeat, fast breathing or shortness of breath, confusion or clumsiness, a fit (seizure), or loss of consciousness. Call emergency services, as these can be signs of heatstroke, and do not drive yourself. The warning stage before it is heat exhaustion: tiredness, dizziness, headache, feeling sick or being sick, heavy sweating with pale clammy skin (harder to see on brown or black skin), cramps in the arms, legs or stomach, a high temperature, feeling very thirsty, or feeling irritable. Get out, move to a cool place, take off any extra clothing, drink water, and cool the skin by spraying or sponging it with cool water and fanning. Call emergency services if you are still unwell after 30 minutes of resting, cooling and drinking.
- Emergency: after cold water, shivering that does not settle once you are out, dry and wrapped up, pale, cold, dry skin, lips that look blue or grey, slurred speech, slow breathing, or feeling tired or confused. These can be signs of hypothermia. Go to an emergency department or call emergency services, and do not drive yourself. Move somewhere sheltered, get out of wet clothes and wrap up in a blanket or a dry towel, and do not use a hot bath, a hot water bottle or a heat lamp to warm up, do not rub the arms, legs, hands or feet, and do not drink alcohol.
- Emergency: dark pee (brown, red or tea-colored) after exercise, or muscles that become badly swollen, extremely painful or too weak to use, are not normal soreness. Go to an emergency department straight away, as these can be signs of serious muscle damage (rhabdomyolysis).
Common questions
Does a cold plunge after a workout kill gains?
It takes a small bite out of them, on the evidence that exists, and the phrase is wider than what was measured. A 2024 systematic review with meta-analysis pooled 8 interventions with 116 participants between them, comparing 4 to 12 weeks of resistance training against the same training followed by cold water immersion. The pooled comparison favored training without the cold, at a comparative standardized mean difference of -0.22 (95% credible interval -0.47 to 0.04), with the probability that the true difference sits below zero put at 0.957 (Pinero and colleagues, 2024). Four limits travel with that figure: every trial applied the cold within 15 minutes of finishing and the authors say the result applies only to that timing; the immersions were 10 to 20 minutes at 10 to 15 C (50 to 59 F); only 1 of the 8 studies included any female participants; and on the review's own quality tool no study scored as good, 3 were fair and 5 were poor. The review measured muscle size and not strength, and its authors point to a study where cold water reduced gains in size but not in strength in the same group of people.
Is a cold plunge good or bad after a workout?
Both, depending on what you want from the next 24 hours, which is why the search results argue with each other. For building muscle it is mildly unhelpful: pooling 8 training studies with 116 participants between them, cold water within 15 minutes of the last set came out behind training alone (Pinero and colleagues, 2024). For performing again soon it is mildly helpful: pooling 52 trials, muscular power 24 hours after high-intensity exercise favored cold water at a standardized mean difference of 0.22 (95% confidence interval 0.004 to 0.43) across 17 studies and 278 participants, and perceived recovery at 0.66 (0.29 to 1.03) across 5 studies and 79 participants (Moore and colleagues, 2022); neither effect is large, and the review rated the certainty of both estimates as moderate. Anyone who has a heart condition needs a doctor's go-ahead before cold water, because entering it raises heart rate and blood pressure sharply (British Heart Foundation, 2023). If your blood pressure is not under control, leave the cold water until it is: the usual advice before starting exercise is to check with your doctor, but exercise is worth that conversation and a cold plunge has nothing to lose by waiting.
Should I use an ice bath or a sauna after a workout?
Judge it by the goal, because the two have been studied for different purposes and the heat side is much thinner. Cold water has training studies behind it on both counts: a small reduction in muscle growth when used within 15 minutes of a strength session, and a small gain in next-day power and perceived recovery after hard work (Pinero and colleagues, 2024; Moore and colleagues, 2022). Heat has no answer yet: a 2025 systematic review found 14 studies with 194 participants, split 9 on acute recovery and 5 on training adaptation. The spread of designs and heating protocols ruled out any pooling, the authors rated the overall quality of the evidence as low to moderate, and they concluded that definitive conclusions are not possible (Ahokas and colleagues, 2025). If you enjoy a sauna, enjoy it, but check with your doctor first if you have a heart condition or high blood pressure, and keep alcohol out of it.
How long and how cold is an ice bath in the research?
In the 8 training studies pooled in 2024 the immersions ran 10 to 20 minutes at 10 to 15 C (50 to 59 F), starting 3 to 15 minutes after the session finished, and 6 of the 8 used 10 C (50 F) (Pinero and colleagues, 2024). That is a description of what was tested, not a recommendation for you, and it is the protocol behind the finding that cooling that soon after lifting slightly reduced muscle growth. A separate meta-analysis of 52 recovery trials reported that shorter durations and lower temperatures appeared to work better when cold water was used after high-intensity exercise (Moore and colleagues, 2022). Before copying any of it, note that the British Heart Foundation puts 26 to 33 C (79 to 91 F) as the safest water range for people with heart conditions, which is warmer than every protocol above (British Heart Foundation, 2023).
Is a sauna after a workout safe?
In the trial literature it has been uneventful, and the wider medical literature is where the serious events live: a systematic review of 40 studies with 3,855 participants in total found the reported harms were mild to moderate heat discomfort or intolerance in 4 of those studies, low blood pressure with light-headedness in 1, airway irritation in 2, and transient leg pain and claustrophobia in 1 each, with no severe symptom anywhere in them needing emergency medical services. The same review lists what the broader literature contains, including burns, heart muscle ischemia especially in people with unstable coronary artery disease, fainting and falls, heatstroke and muscle breakdown, and it cites retrospective population studies of frequent sauna users reporting annual sauna death rates of 0.06 per 100,000 inhabitants in Sweden and 2 per 100,000 in Finland, with half or more of those deaths involving alcohol (Hussain and Cohen, 2018). So: no alcohol, get out when you have had enough rather than when the timer says so, do not use a sauna or a cold tub on your own, and ask your doctor first if you have a heart condition or high blood pressure; come out at the first signs of heat exhaustion too, which the NHS lists as tiredness, dizziness, headache, feeling sick, heavy sweating with pale clammy skin, cramps or being very thirsty, and cool down in a cool place with a drink of water. If you are pregnant, the NHS answer to this question is that there is little research on saunas, jacuzzis, hot tubs and steam rooms in pregnancy, that you may choose to avoid them because of the risks of overheating, dehydration and fainting, that a significant rise in core temperature could be harmful particularly in the first 12 weeks, and that it is best to avoid hot tubs, which can reach 40 C (104 F) (NHS advice on saunas and jacuzzis in pregnancy); nobody has studied cold plunging in pregnancy either, so ask your own midwife or maternity team before using either end of the thermometer. If chest pain, pressure or tightness does not ease quickly when you rest, spreads to your arm, neck, jaw, stomach or back, or comes with sweating, feeling sick, feeling light-headed or being short of breath, call emergency services straight away, as this can be a heart attack.
Does a cold plunge help if I am competing again tomorrow?
That is the situation where it has the most support, and the support is still modest. Pooling 52 randomized trials of cold water immersion against passive rest after one hard session, the outcomes that favored cold water 24 hours after high-intensity exercise were muscular power, at a standardized mean difference of 0.22 (95% confidence interval 0.004 to 0.43) from 17 studies and 278 participants, perceived recovery at 0.66 (0.29 to 1.03) from 5 studies and 79 participants, and the blood marker creatine kinase at -0.85 (-1.61 to -0.08) from 5 studies and 105 participants. Strength at 24 hours showed no difference, at 0.12 (-0.38 to 0.62), and that estimate came from only 3 studies and 62 participants (Moore and colleagues, 2022). After eccentric exercise specifically, power was the only outcome that favored cold water at 24 hours. The adaptation cost of one plunge on a competition weekend is small, so this is the one use that survives the muscle growth argument intact.
References
- Pinero A, Burke R, Augustin F, Mohan AE, DeJesus K, Sapuppo M, Weisenthal M, Coleman M, Androulakis-Korakakis P, Grgic J, Swinton PA, Schoenfeld BJ. Throwing cold water on muscle growth: a systematic review with meta-analysis of the effects of postexercise cold water immersion on resistance training-induced hypertrophy. European Journal of Sport Science. 2024;24(2):177-189. https://doi.org/10.1002/ejsc.12074
- Moore E, Fuller JT, Buckley JD, Saunders S, Halson SL, Broatch JR, Bellenger CR. 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 Medicine. 2022;52(7):1667-1688. https://doi.org/10.1007/s40279-022-01644-9
- Ahokas EK, Hennessy RS, Hanstock HG, Kyrolainen H, Ihalainen JK. Effects of post-exercise heat exposure on acute recovery and training-induced performance adaptations: a systematic review. Sports Medicine Open. 2025;11:106. https://doi.org/10.1186/s40798-025-00910-0
- Hussain J, Cohen M. Clinical effects of regular dry sauna bathing: a systematic review. Evidence-Based Complementary and Alternative Medicine. 2018;2018:1857413. https://doi.org/10.1155/2018/1857413
- British Heart Foundation. Cold water swimming: is it bad for your heart? Published 31 May 2023. https://www.bhf.org.uk/informationsupport/heart-matters-magazine/activity/cold-water-swimming
- NHS. Chest pain. Page last reviewed 8 August 2023. https://www.nhs.uk/symptoms/chest-pain/
- NHS. Fainting. Page last reviewed 17 August 2026. https://www.nhs.uk/conditions/fainting/
- NHS. Heat exhaustion and heatstroke. Page last reviewed 28 May 2026. https://www.nhs.uk/conditions/heat-exhaustion-heatstroke/
- NHS. Hypothermia. Page last reviewed 9 June 2023. https://www.nhs.uk/conditions/hypothermia/
- NHS. Is it safe to use a sauna or jacuzzi if I am pregnant? NHS patient information, republished on an NHS GP practice website; no longer listed on nhs.uk. Accessed 1 October 2026. https://collingwoodsurgery.nhs.uk/new-york/common-questions/pregnancyis-it-safe-to-use-a-sauna-or-jacuzzi-if-i-am-pregnant
- Cleveland Clinic. Rhabdomyolysis. Last updated 24 February 2023. https://my.clevelandclinic.org/health/diseases/21184-rhabdomyolysis
Written and checked by the PocketPhysio editorial team. Last updated 2026-10-01.
This page is general education, not a diagnosis or a personal treatment plan. See a physiotherapist or doctor for advice about your own situation.