You’re probably sick of hearing this, but the importance of drinking enough water while exercising, especially during the warmer months, cannot be emphasised enough.

When we exercise, we build up heat in working muscles causing our internal temperatures to rise. We cool ourselves by perspiring. It is this evaporation of sweat from our skin that helps us maintain a lower core body temperature. When there is a lot of moisture in the air, evaporation isn’t an effective cooling means and we keep sweating and losing fluids in order to try and stay comfortable. As a result, we have to drink more water to replenish this lost fluid.

The first drawback to dehydration is diminished performance. The water we lose through sweating comes from blood plasma. Plasma is the vehicle for red blood cells, which contain the oxygen that muscles need in order to perform. As you become dehydrated, your total blood volume is reduced, and the oxygen-carrying capability of your blood decreases. If you continue to exercise without proper fluid intake, you may experience a drop in blood pressure, feel faint, dizzy or nauseous. These are the symptoms of heat exhaustion. If you keep going, your body's ability to dissipate heat is further impaired and you may suffer heat stroke.

During heat stroke, your temperature can rise above 41 degrees Celsius. At this point, you no longer sweat, and seizures, coma or even death may result. Remember, blood not only carries oxygen to your working muscles, it sends it to all of our vital organs, like the brain.

How do you get enough water? Drink a glass of water every fifteen minutes during your workout. This may sound like a lot, but it is necessary to keep you hydrated. If you can't drink that much water at once, take smaller amounts every ten minutes.

You should follow the same guidelines when exercising indoors. Even if the air conditioning is on, you still sweat a lot if you spend 45 minutes or more on a stepper, treadmill or stationary bike. Don’t assume you have to be outdoors for serious dehydration to occur.

Don't wait until you're thirsty to start drinking. The sensation of thirst is triggered by the hypothalamus in the brain. It measures the concentration of salts in your blood. As blood volume decreases due to sweating, your concentration of salts goes up, and the hypothalamus sends the signal to start drinking. By the time you feel thirsty, you are already dehydrated.

How can you be sure you're drinking enough water? When your urine is clear, rather than yellow, you are sufficiently hydrated. Make sure you keep drinking water after exercise. If you can weigh yourself before and after a workout, a good rule of thumb is to drink one pint of water for every pound you've lost.

Don't forget that caffeinated beverages are diuretics. These drinks make you pee and lose fluid quickly, so you’ll need an additional glass of water for each cup of coffee or fizzy drink you have. Alcohol also dehydrates you, so for every beer or vodka you enjoy, match it with a glass of water.

All of these recommendations are, of course, in addition to the eight glasses of water per day that we know you are already drinking.