Considering that water makes up about 60 percent of our body mass, it is surprising that it is often overlooked as a key contributor to the proper functioning of so many systems, from temperature regulation to blood volume, and a whole range of things in between. We rely on water to dissolve waste products like ammonia (a by-product of protein metabolism) and for carrying vitamins such as vitamins C and B complex which are water soluble, around the body for use as catalysts and co-factors for reactions such as collagen production and cell division. If we become dehydrated – the state of losing more fluid than we replace – then all of these systems become impaired. In the short term this can lead to fatigue, and also constipation as fluid is reabsorbed from food waste in the colon leaving less lubrication. In the long term, it can cause urinary tract and kidney problems.

The European Food Safety Authority recommendation for adequate intakes of fluid per day is 2l for women and 2.5l for men, although how much you need really depends on what your losses are. Losses of fluid occur primarily through vapour in the breath during gas exchange; urine when excreting waste and sweat which is the mechanism for temperature control. Thirst is the most recognisable sign of dehydration but there are often other symptoms that come before thirst that may not necessarily be associated with a lack of fluids. Poor concentration, fatigue, a drop in fine and gross motor skills too. So, if you are exercising or playing sports, proper hydration can mean accurately getting the football in the goal or not tripping over when running. It’s also very hard to thread a needle and you may notice that you are making more typos if you are not properly hydrated.

Hydration is especially important during exercise as water losses are much higher than if you were stationary. We know water is lost when you breathe and when you sweat – both of these are at a much higher rate when you are moving. Remember that regulation of body temperature depends on being properly hydrated and when you move, you get hot. Drinking fluids offsets the fluid you lose keeping you at the right level of hydration.

How proper hydration aids performance

Water is an obvious choice for rehydration and pretty much anything that contains it will contribute to fluid intake, including food with a high water content like soup, vegetables and even pasta, which absorbs a lot of fluid during the cooking process. However, there are ways to speed up the absorption of water to rehydrate more quickly, and that is through the addition of electrolytes, like potassium, to water. These drinks are up to five times more readily absorbed into the body, depending on the electrolyte concentration. Very useful if you are sweating a lot and hot.