Exercising in Hot and Humid Conditions
During the hot summer months exercising can be draining but if you take some simple precautions you do not have to seriously cut back on your training.
When exercising in hot and humid conditions it is essential to stay hydrated. Dehydration is inevitable to some degree because up to 2 litres of sweat can be lost per hour of exercise on hot days while the maximum rate at which fluid can be absorbed is about 1.2 litres per hour. A good way to determine how much fluid you are losing while exercising on hot days is to weigh yourself naked before and after your run. If you weigh one kilogram less after exercise you need to drink one litre of fluid to replace your sweat loss.
Here are some simple rules.
Drink when you feel thirsty
Your desire for fluid is driven by small changes in blood salt concentration and drinking when you feel thirsty will maintain the volume of water inside cells. Always take fluid with you when exercising on hot days and drink when you feel the need.
Some people drink far too much before they exercise on hot days and this can lead to stomach cramps, discomfort and in some cases a lowering of blood salt levels or hyponatraemia.
Isotonic rather than water
When exercising for more than an hour an isotonic sports drink is better than water. The isotonic drink will provide some carbohydrate to renew energy and replace some of the salt loss through sweating.
Flat drinks are better than fizzy
Carbonated drinks are absorbed more slowly than non-carbonated drinks so go for flat rather than fizzy drinks. Avoid smoothies and fruit juices as these are often energy dense and absorbed more slowly.
Check your urine
Checking the colour of your urine in the morning is a good way to monitor your hydration. If your urine is clear, pale yellow or straw coloured you are well hydrated. If it is darker you are dehydrated.
When exercising in hot and humid conditions