Sauna, Ice Baths and Cold Showers: What the Evidence Says About Heat and Cold
Saunas, steam rooms, ice baths and cold showers are everywhere on fitness social media, sold as recovery, fat loss, immunity and longevity in one. The research supports some of it, contradicts some of it, and adds an important warning for people who lift weights. Here is what heat and cold actually do, and how to use them safely.
By Taha Raza
Published
Contrast therapy, cold plunges, infrared saunas and steam rooms have moved from Scandinavia and elite sport into ordinary gyms, hotels and home bathrooms. In Lahore, steam rooms and saunas are common in gyms and clubs, and ice-bath videos are everywhere. The question for most people is simple: does any of it help my health or my training?
Is sauna good for your heart?
The best-known evidence comes from Finland. The Kuopio study followed 2,315 men aged 42 to 60 for a median of 20.7 years. Compared with men who used a sauna once a week, those using it 4–7 times a week had a 63 percent lower risk of sudden cardiac death after adjustment for other risk factors, and similar trends for heart disease and death from any cause; longer sessions of more than 19 minutes were also linked to lower cardiac risk. Over the study, 30.8 percent of the frequent users died compared with 49.1 percent of once-a-week users. This is a striking finding, but it is observational: men who use a sauna daily may differ in health, income and activity. Sauna heat raises heart rate in a way that resembles light exercise, which is a plausible reason for a benefit, but it is not a substitute for exercise.
| Practice | Evidence | Verdict |
|---|---|---|
| Sauna 4–7 times a week | 63% lower sudden cardiac death vs once a week (2,315 Finnish men, observational) | Promising association; not proof |
| Ice bath for soreness | Slightly less soreness vs passive rest; 10–15 °C works best (9 trials) | Small benefit |
| Ice bath after strength training | Less strength and muscle gain over 12 weeks; harmful in 2021 meta-analysis | Avoid if building muscle |
| Ice bath with endurance training | No effect on endurance gains in 2021 meta-analysis | Neutral |
| Cold showers daily | 29% less sickness absence, no fewer illness days (3,018 people) | Modest, uncertain |
| Sauna or cold for fat loss | Weight lost in a sauna is water and returns with drinking | No meaningful fat loss |
Do ice baths help recovery?
A little, for soreness. A 2016 meta-analysis of 9 trials found cold water immersion reduced muscle soreness slightly more than passive rest, both immediately and over the following days, with water at 10–15 °C giving the best results. The effect is modest. For athletes who need to perform again within hours or a day — a tournament, a match the next day — that can be worth it. For most people training a few times a week, soreness fades on its own; our DOMS guide covers what helps.
Do ice baths kill muscle gains?
Used regularly after lifting, they seem to. In a 2015 trial in the Journal of Physiology, 21 active men did 12 weeks of strength training twice a week, followed by either 10 minutes in cold water or an active recovery on a bike. Strength and muscle mass rose more in the active-recovery group; muscle fibre size and other markers increased only in that group. Biopsies showed the cold blunted the signals that drive muscle growth. A 2021 meta-analysis in Sports Medicine confirmed a harmful effect of regular cold water immersion on strength gains, but found no effect on endurance gains. If muscle and strength are your goal, keep ice baths for rest days or skip them, and do not jump in the cold within a few hours of lifting.
Are cold showers good for you?
Possibly, a little. A Dutch trial randomly assigned 3,018 adults to finish their usual hot shower with 30, 60 or 90 seconds of cold water every day for 30 days, or to keep showering normally. The cold-shower groups had 29 percent less sickness absence from work, but no fewer days of illness — they felt ill as often but took fewer days off. Many people also report feeling more alert. It is cheap and safe for healthy people; just do not expect it to prevent illness.
Does sauna help you lose weight?
No. The weight lost in a sauna or steam room is sweat, and it comes back as soon as you drink. Sweating it out before a weigh-in, or using sauna suits and belts, risks dehydration, especially in Pakistani heat, and does nothing for body fat. Our belly fat guide explains what does work.
Who should avoid saunas and cold plunges?
- People with heart disease, chest pain, an irregular heartbeat, a recent heart attack, or uncontrolled high or low blood pressure — ask your doctor first. Sudden cold immersion triggers a gasp reflex and a surge in heart rate and blood pressure (the 'cold shock' response), which is a known cause of cardiac arrest and drowning.
- Anyone who has been drinking alcohol: alcohol plus sauna is a recognised cause of collapse and deaths.
- People who feel dizzy, faint or unwell during a session — get out, sit down and drink water.
- Anyone dehydrated after hard training, fasting or a hot day: drink before and after, and keep sessions to 10–20 minutes.
- Cold plunges alone or in open water: never get in without someone nearby, and never put your face under water when you first get in.
This article is general information, not medical advice. If you have heart disease, blood pressure problems, diabetes with nerve damage, or take regular medicines, talk to your doctor before using saunas, steam rooms, ice baths or cold plunges.
Frequently Asked Questions
Is sauna good for you?
For healthy people it appears safe and may benefit the heart. Finnish men who used a sauna 4–7 times a week had a 63 percent lower risk of sudden cardiac death than once-a-week users, though the study was observational. Drink water and avoid alcohol.
Do ice baths stop muscle growth?
Regular ice baths after lifting seem to. In a 12-week trial, a 10-minute cold bath after strength training led to smaller gains in strength and muscle, and a 2021 meta-analysis confirmed a harmful effect on strength. Keep them away from lifting days.
Are cold showers good for you?
Mildly. In a trial of 3,018 adults, ending a shower with 30–90 seconds of cold water cut sickness absence by 29 percent, but did not reduce days of illness. It is safe for healthy people.
Does sauna burn fat?
No. Sauna weight loss is sweat, and it returns as soon as you drink. Fat loss comes from a calorie deficit, protein and training.
How long should I stay in a sauna?
Most people do well with 10–20 minutes. In the Finnish study, sessions longer than 19 minutes were linked to lower cardiac risk, but leave as soon as you feel dizzy or unwell, and drink water before and after.
Is an ice bath or a sauna better for recovery?
Ice baths slightly reduce soreness, best at 10–15 °C, but blunt muscle gains if used after lifting. Saunas do not blunt gains, but their recovery benefits are less studied. For most people, sleep, food and sensible training matter far more.
Sources
- Laukkanen T et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine, 2015
- 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 Medicine, 2016
- Roberts LA et al. Post-exercise cold water immersion attenuates acute anabolic signalling and long-term adaptations in muscle to strength training. Journal of Physiology, 2015
- 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 Medicine, 2021
- Buijze GA et al. The effect of cold showering on health and work: a randomized controlled trial. PLoS One, 2016
- Tipton MJ et al. Cold water immersion: kill or cure? Experimental Physiology, 2017
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