Hydration
Do all drinks count?
With the exception of alcohol, all drinks help to keep us hydrated and they can be enjoyed as part of a balanced diet and healthy lifestyle.
However there are differences between drinks, in terms of their rate of absorption into the body and in the other nutrients they provide. These should be taken into consideration when making choices about what to drink for hydration purposes.
For example plain water and no added sugar squashes will hydrate but will not provide any energy (calories).
Water is an excellent source of hydration but sometimes plain water may be absorbed very rapidly, and this has an impact on the osmoreceptors in the body which send a message to the brain which, in simple terms, turns off the thirst feeling and also stimulates urine output. The composition of many squashes means that they may be absorbed at a slower rate and so there is less likelihood that this thirst mechanism is switched off quickly and potentially before full hydration status is achieved. *
There is a wide variety of sports drinks on the market designed to help replace glycogen stores lost during exercise. They deliver carbohydrates and fluids to the blood stream at different speeds depending on the amounts of carbohydrates and salt they contain.
The addition of carbohydrates (sugars) such as glucose, sucrose or fructose to a drink provides a source of energy for the working muscles. Where rehydration is a priority the sugar content should be low, but where provision of fuel is paramount a higher sugar drink may be used. Very high sugar drinks will hinder fluid absorption and so are not recommended immediately after sport activities.
Caffeine (found in many teas, coffees and colas) is a mild diuretic (it increases water lost in urine) but these drinks can still count towards your daily fluid intake - just not in excessive amounts!
*References:
Maughan RJ, Shirreffs SM, Leiper JB. Rehydration and recovery after exercise. Sport Sci Exc. 1996;9(92):1-5.
Nutrition in Practice: Volume 3 issue 1 keeping the body hydrated why it is necessary and how to achieve it. By Professor Ronald Maughan and Dr Susan Sheriffs, University Medical School Aberdeen.
M. Saltmarsh. Thirst: or, why do people drink? Nutrition Bulletin. 2001;26(1):53-8.
