They had "experts" talking about it on the BBC programme last night, being thirsty is your body's way of telling you it's time to drink. The previous perceived wisdom of drinking before your thirsty appears to be a ploy from drinks companies to get you to consume(buy) more of their products.
Fair enough, but judging by the general sloppiness of BBC reporting I’d take that with a pinch of salt (or isotonic lucazade). As for marketing by drink’s companies, again, the conceived wisdom is to drink tap water. Personally I’d listen to the NHS on this over the BBC:
Quote from http://www.nhs.uk/Conditions/dehydration/Pages/Introduction.aspx :
Some of the early warning signs that you're dehydrated include:
- feeling thirsty and lightheaded
- having dark coloured, strong-smelling urine
- passing urine less often than usual
· How much should we drink?
· Many studies have tried to establish a recommended daily intake of fluid, but it can vary depending on the individual and on factors such as age, climate and physical activity.
Some studies in the UK suggest that adults should drink 1.2 litres (6-8 glasses of water) per day to replace lost fluids and
prevent dehydration.
· A good general recommendation is to drink enough fluid so that you're not thirsty for long periods of time, and to steadily increase your intake during exercise or hot weather.
· You should also drink fluid if you're having symptoms of dehydration, such as feeling thirsty and lightheaded, passing dark-coloured urine or not passing urine within six hours. It's also important to replace fluid lost after an episode of diarrhoea in order to prevent dehydration.