Dehydration is the excessive loss of body fluid, which can adversely affect athletic performance.
Symptoms
Sluggishness
Fatigue
Headaches
Loss of appetite
Feeling very hot
Lightheadedness
Nausea
Exercise is thirsty work. Whenever you exercise you lose fluid, and if this fluid is not replaced quickly, dehydration will follow. This will have an adverse effect on your performance and health, exercise will be much harder, and you will suffer fatigue sooner.
Why do we sweat?
Sweating is the body’s way of regulating your temperature so that you do not overheat. What are the dangers of dehydration?
A 2% loss of body weight in sweat results in up to 20% less physical performance.
If you lose 4%, you may experience nausea, vomiting and diarrhoea.
And an 8% drop will cause dizziness, laboured breathing, weakness and confusion.
Greater drops can have very serious consequences, circulatory collapse and heat-stroke, which can be fatal.
You should produce dilute, pale-coloured urine. A small volume of dark coloured urine indicates you are dehydrated and is a signal to drink more before you exercise.
If you are thirsty, you are already dehydrated, and your performance will be suffering!
The three main types of sports drinks
Hypotonic – contains less than 4g carbohydrate per 100ml and is absorbed faster than water.
Isotonic – contains between 4 and 8g carbohydrate per 100ml and is absorbed at the same rate or faster than water.
Hypertonic – contains more than 8g carbohydrate per 100ml and is absorbed more slowly than water.
Hydration Advice
Always start exercise well hydrated, drink 500ml fluid 2 hours before exercise
During exercise, start drinking early and at regular intervals, aim for 125-250ml every 10-20 minutes
After exercise, replace by 150% any body weight deficit (weigh before and after exercise)
Water is a suitable fluid replacement drink for low to moderate intensity exercise lasting less than an hour
For intense exercise, lasting up to an hour, a sports drink containing up to 8g carbohydrate per 100ml will speed up water absorption, provide additional fuel and delay fatigue
Hypotonic and isotonic sports drinks are the most suitable when rapid fluid replacement is the main priority
The main purpose of sodium in a sports drink is to increase the urge to drink
For a person not exercising it is recommended they drink eight glasses of water a day
