As a basic guide, most people need about 1.5 to 2 litres of fluid each day, which is about 8 to 10 glasses. Except from water, hydration can be achieved also from other drinks, such as milk and fruit juice, and fruit and vegetables, such as cucumber, lettuce and tomatoes.

The main sign of dehydration is thirst, the Club notes, but good indicators are also the number of times you go to the toilet and the colour of your urine, it should be pale yellow. If you don’t need to go often, you only pass a little urine each time and it's dark in colour, it’s likely that you’re dehydrated.

Other signs of dehydration  include:

•    headache
•    feeling weak and dizzy
•    tiredness 
•    dry mouth and lips and eyes
•    feeling confused
•    cramps

Recommendations

The Club cited the following advice:

  • If you think that you may be dehydrated, you need to rehydrate your body by drinking fluid. For mild dehydration, the best way to hydrate is by drinking water. It’s better to drink little and often rather than trying to drink a lot all in one go because this may make you vomit.
  • If you have more serious dehydration that’s caused by diarrhoea or vomiting, you’ll also be losing important salts and sugars from your body. A good way to replace these is with rehydration sachets, which you add to water.
  • If you have more severe dehydration in addition to the above mentioned signs you may also notice a weak or rapid pulse, low levels of consciousness and seizures.  If there are signs of severe dehydration immediate medical advice must be sought.