Water and the Sauna: How Much to Drink, When, and What
19.07.2026
Everyone has an opinion about drinking in the sauna, and most of those opinions are vague. Advice swings between drink as much as you can and drink nothing so you sweat more, and both extremes are poor ideas. The reality is simple and practical: you lose fluid faster than usual in the heat, and that loss needs replacing gradually.
How much you sweat is highly individual. It depends on temperature, humidity, how many rounds you do, your build, and how accustomed you are to heat. Precise millilitre targets are therefore useless as a universal rule. A far more helpful guideline is to drink regularly in small amounts, and afterwards to pay attention to how you feel over the following hours.
Before your session, have a glass or two of plain water, but do not try to stockpile fluid. A large volume immediately before heat only creates heaviness and unnecessary load. If you are already thirsty or dry-mouthed before you start, that is a sign you are beginning at a deficit - better to delay the first round by ten minutes and simply drink.
Between rounds, the principle is less and more often. A glass of water after each round is usually enough. Keep it at room temperature or lukewarm; a very cold drink straight after heat is uncomfortable for many people. Warm herbal tea is a good alternative and plenty of people find it more pleasant than plain water.
One important and frequently forgotten detail is salt. Sweat carries away sodium and other electrolytes, and drinking only large volumes of plain water can shift the balance in the wrong direction rather than the right one. In practice this is easy to solve: eat something salty afterwards - a warm broth, a pickled cucumber, cheese or bread. Specialist sports drinks are not necessary; ordinary food does the job just as well.
Alcohol has no place here. It speeds up fluid loss, alters blood pressure and, more importantly, blunts your ability to judge your own state at exactly the moment when that ability matters most. Sugary fizzy drinks are also a poor choice: they do not satisfy thirst and produce an unsteady energy curve.
How do you recognise that you are short of fluid? Typical signs are a dry mouth, headache, unusual tiredness after the session, dizziness on standing, very dark urine, or a racing heart at rest. If any of these appear, stop doing rounds, cool down, sit and drink gradually. If things do not improve, seek medical help.
One more common mistake happens after the session: people drink a great deal late in the evening and are then surprised by restless sleep. It works far better to start drinking between rounds and continue steadily through the evening than to swallow a litre right before bed. If you take diuretics or blood pressure medication, or you have kidney or heart conditions, or you are pregnant, discuss your fluid plan for a sauna day with your doctor. General advice is not enough in these situations, and individual guidance is considerably safer.
How much you sweat is highly individual. It depends on temperature, humidity, how many rounds you do, your build, and how accustomed you are to heat. Precise millilitre targets are therefore useless as a universal rule. A far more helpful guideline is to drink regularly in small amounts, and afterwards to pay attention to how you feel over the following hours.
Before your session, have a glass or two of plain water, but do not try to stockpile fluid. A large volume immediately before heat only creates heaviness and unnecessary load. If you are already thirsty or dry-mouthed before you start, that is a sign you are beginning at a deficit - better to delay the first round by ten minutes and simply drink.
Between rounds, the principle is less and more often. A glass of water after each round is usually enough. Keep it at room temperature or lukewarm; a very cold drink straight after heat is uncomfortable for many people. Warm herbal tea is a good alternative and plenty of people find it more pleasant than plain water.
One important and frequently forgotten detail is salt. Sweat carries away sodium and other electrolytes, and drinking only large volumes of plain water can shift the balance in the wrong direction rather than the right one. In practice this is easy to solve: eat something salty afterwards - a warm broth, a pickled cucumber, cheese or bread. Specialist sports drinks are not necessary; ordinary food does the job just as well.
Alcohol has no place here. It speeds up fluid loss, alters blood pressure and, more importantly, blunts your ability to judge your own state at exactly the moment when that ability matters most. Sugary fizzy drinks are also a poor choice: they do not satisfy thirst and produce an unsteady energy curve.
How do you recognise that you are short of fluid? Typical signs are a dry mouth, headache, unusual tiredness after the session, dizziness on standing, very dark urine, or a racing heart at rest. If any of these appear, stop doing rounds, cool down, sit and drink gradually. If things do not improve, seek medical help.
One more common mistake happens after the session: people drink a great deal late in the evening and are then surprised by restless sleep. It works far better to start drinking between rounds and continue steadily through the evening than to swallow a litre right before bed. If you take diuretics or blood pressure medication, or you have kidney or heart conditions, or you are pregnant, discuss your fluid plan for a sauna day with your doctor. General advice is not enough in these situations, and individual guidance is considerably safer.