Medical Q&As

Potassium loss - causes?

I have been drinking two to three litres of water per day and have heard recently that drinking too much water can deprive your body of potassium. Is this correct? Should I decrease my intake? I train a lot in the gym and sweat a lot and feel the need to drink extra water to rehydrate. Am I doing something wrong?

The information you have been given is incorrect and you should continue drinking water as you have been because of your vigorous exercise schedule. The level of fluid you are drinking will not wash out potassium from your body. Your kidneys regulate the volume of urine you excrete in order to maintain the correct fluid balance in your body. If you lose a lot of fluid in the form of perspiration the kidneys conserve fluid and you pass less urine and when you replace that fluid by drinking water the volume of urine increases again to normal levels. The adrenal gland also plays a part in this process through the production of aldosterone, which is a hormone that regulates potassium excretion or retention depending on the body’s needs. A low potassium level is known as hypokalaemia and this can occur in a number of situations. It can occur as a result of disorders of the adrenal gland, severe diarrhoea, diuretic therapy and can occasionally happen in the case of dietary deficiency. Hypokalaemia will not occur as a result of fluid replacement following exercise.