Water is an essential nutrient that contains no calories whatsoever. In actual fact, drinking water causes a thermogenic response within the body and this uses calories. It is estimated that consuming 500ml of water (a small bottle of water) requires the body to expend 24 calories. Therefore drinking two litres of water encourages an increase in your metabolic rate, with an increased expenditure of around 96 calories.

There is no magic number for how much water we should be drinking each day. Your required intake will be partly determined by your body size, level of physical activity and the environment that you are in but general recommendations are between 2-3 litres/day.

  • Exercise – If you partake in any form of physical activity it is likely that you will need to drink extra water to remain hydrated. The duration and type of exercise both affect the amount of additional fluid required as will the rate at which you sweat. For short bouts of exercise, around 400-600ml of extra water should be sufficient however for more intense exercise bouts of longer duration (over 1 hour) it will be necessary to consume more water.
  • Environment – It is likely that you will sweat more in humid and hot environments and this will require you to consume extra fluid to replace this loss. It should also be noted that if you are subjected to altitudes greater than 8,200 feet (2,500 meters) that your breathing rate and urination are likely to increase and again will require you to consume additional water.

It is very important for us to remain hydrated. Even a very small level of dehydration can lead to a reduction in mental and physical performance (percentage indicates fluid loss as a percentage of body weight):

  • 1%: Feelings of thirst, impaired thermoregulation
  • 2%: Impaired mental performance
  • 4%: 20-30% reduction in work capacity
  • 6%: Tingling and numbness of extremities
  • 7%: Collapse
  • 10%: Life-threatening

A few tips… 

  • Keep a bottle of water on your desk to encourage regular fluid intake
  • Increase your daily antioxidant intake through drinking hibiscus tea.
  • Soda water – drink in moderation as carbonated drinks can leach calcium from bones.
  • Try flavouring water with a slice of fruit such as lemon or lime for taste.
  • Avoid drinking flavoured water drinks – these can be high in sugar (500ml of some brands contains 15g of sugar, the equivalent of nearly four teaspoons of sugar).

With nearly a quarter of the added sugar in our diets coming from sugary drinks such as fizzy drinks, sweetened juices, squashes and cordials (500ml of cola contains the equivalent of 17 cubes of sugar), the simple choice of opting for water over other drinks on the market can have huge benefits for your health.