To stay healthy, it's important to replace the fluids we lose when we sweat, breathe and urinate by drinking water.
But a health expert has warned that many of us are are going over the top when it comes to hydration and actually drinking too.
According to Professor Mark Whiteley, a consultant vascular Surgeon at The Whiteley Clinic, London, the behaviour has led to a rise in people coming to see him at about hyperhidrosis - the excessive sweating condition.
Speaking to the MailOnline, Whiteley said hundreds of patients visit him each year suffering from hyperhidrosis. Many ask whether they can have their sweat glands removed, but in the majority of cases this is unnecessary.
The patients are simply drinking too much fluid.
"Lots of advertisers advertise water and say you have to drink two or three litres a day. That’s medically incorrect. If you go to intensive care you will be but on 1.5 litres of fluid per 24 hours," he said.
"If you drink more, your kidneys have to work extra hard to get rid of this fluid load. Then you sweat it out, which makes people sweat even more."
According to Whiteley, we should focus on drinking when we're thirsty, rather than drinking because we're sweating.
However, he does note that there are people who suffer from hyperhidrosis which is not linked to their fluid intake. These people may require treatment beyond cutting down on liquids. They should see thier GP for further advice.
Whiteley isn't the first medical expert to suggest that drinking too much water can have a detrimental affect on health.
Writing in the British Medical Journal, Dr. Margaret McCartney previous referred to the health recommendation to drink six to eight glasses of water per day as "thoroughly debunked nonsense".
She said drinking too much water can be dangerous as it causes low blood sodium levels (a condition called hyponatraemia) and exposes people to pollutants in the water.
"People still think that we're all going to die or our kidneys will shrivel up if we don't drink eight cups of water a day," she added.
"From what I can see, there's never been any evidence in the medical literature about it."
That's about eight glasses of 200ml each for a woman, and 10 glasses of 200ml each for a man.
However, the amount of liquid a person needs to drink will vary depending on factors such as whether they are exercising and what the weather is like.