When we exercise, our muscles produce heat. For effective performance our body needs to keep heat levels within safe limits, around 37/38°C. In order to keep our body temperature at the right level we sweat. Sweating gets rid of heat from the body through evaporation.
It is important to continually replace the fluid and electrolytes lost in sweat in order maintain hydration otherwise dehydration will occur and performance will suffer. Dehydration by as little as 2% of body mass can reduce both mental (concentration, reaction time) and physical (endurance) performance.
Sweat and electrolyte loss is dependant on exercise intensity and duration, environmental conditions and the type of clothing worn. Individual factors such as body weight, heat acclimatisation and fitness will also influence sweat rate for any activity. As a result, an individual’s sweat response can vary greatly.