When you exercise, your body endures many physiological and metabolic processes that produce heat, causing you to sweat, lowering your core temperature and reducing the fluid in your body. You can sweat up to 2 litres per hour with intense exercise, especially in the in the heat. If you don’t replace this fluid, you will become dehydrated, which can negatively affect your workout and overall health.
Sweat and the Environment
Your perspiration rate is influenced a lot by temperature and humidity. In warm conditions and peak sunlight, your body temperature rises rapidly, causing you to sweat quickly and more profusely. In high humidity, sweat doesn’t evaporate as readily, so your body keeps producing more in an effort to keep cool. You don’t sweat as much under cool or windy conditions because your body temperature remains steady for longer and the wind speeds up evaporation of your sweat. Your body adjusts to the environment in which you live, so if you are accustomed to warm, humid temperatures, you will sweat less than someone not used to them. Obviously, in the UK we are not used to the warm temperatures or humidity, so exercising in the heat may seem difficult as it is not the norm for our bodies.
Your age and gender determine how much fluid you lose through sweat. Females tend to sweat less because they have smaller bodies and lower metabolic rates than males. Young children don’t sweat as profusely as adults for the same reasons. Older individuals tend to sweat more.
Lessen Fluid Loss
If you are physically in shape, it takes longer for your body to increase heart rate, breathing rate and other metabolic processes, so your body temperature stays steady. You won’t sweat immediately, and when you do you won’t sweat as much as someone just starting an exercise programme. However, this isn’t always the case, as the fitter you become, the harder you can work and the more you sweat. In addition, the more clothing you wear, the more fluid you lose. Your body temperature will rise faster with a lot of layers, and sweat will not evaporate as quickly. Your body will not cool as rapidly, so you end up wasting fluids.
Replacing Fluid Loss
The American College of Sports Medicine recommends you consume 500ml – 750ml water at least four hours before exercising and another 300ml – 500ml around 10 to 15 minutes before starting. During exercise, drink 100ml to 250ml of water every 15 to 20 minutes. To monitor fluid loss during exercise, weigh yourself before and after your workout session. For every pound you lose, consume 500ml of water.