The American College of Sports Medicine recommends that during activity you should consume about half to one full glass of fluid every 15 minutes, as this approximates the rate at which you lose body fluid through sweating. However, some individuals may require more or less due to differences in exercise intensity and humidity conditions.

Did you know...

	Some highly trained athletes have been recorded to sweat up to 3 litres per hour and 15 litres per day (that's around 20% of body weight in one day!)1.
	In humans, thirst is a poor indicator of hydration status. If you are thirsty you may already be dehydrated2.
	For every litre of sweat lost during activity, your heart rate will increase by about 8 beats per minute and your core temperature will increase by 0.3 °C3.

1. Maughan (2001). Fundamentals of sports nutrition: application to sports drinks. In: Maughan & Murray, Sports Drinks - Basic science and practical aspects (Eds). CRC Press: New York.

2. Wilmore & Costill (1999). Physiology of Sport and Exercise. (2nd Edition) Human Kinetics. Publishing Company, Champaign, Illinois.

3. Coyle (1994). Fluid and carbohydrate replacement during exercise: how much and why? Sports Science Exchange. 7(3):Ed 50.