Goal: To prevent excessive dehydration (>2% body weight loss) and large fluctuations in electrolyte balance.
The amount and rate at which you should replace fluids depend on your sweating rate, exercise duration, and opportunity to drink. You should drink periodically during exercise whenever you can.
Your sweating rate and sweat electrolyte concentrations are influenced by:
- Type of exercise
- Weather condition
- Genetic predisposition
- Heat acclimatisation
- Training status
Therefore, fluid replacement varies from person to person. You may estimate your sweat loss during a particular activity by monitoring your change in body weight during exercise.
For endurance exercise, it is recommended that fluid be replaced at a rate of 0.4-0.8L/hour, varying depending on weight, exercise intensity, and environment. However, individuals engaging in different types of physical activity under more intense conditions may have greater needs. Fluid should be consumed frequently (every 5-20 minutes) in small amounts (150-200mls).