Motorsport drivers are subjected to high temperatures and humidity within the cockpit because of heat generated by the engine and exhaust systems. Temperatures in the cockpit can exceed 50°C and you’re often exposed to these conditions for several hours. Protective clothing can make the heat problem worse by creating a microclimate, reducing air flow to your skin, blocking ventilation and reducing heat loss. Driving at 50°C reduces your driving and mental performance and significantly increases sweat loss, core temperature and heart rate. If you don’t keep your fluid levels topped up, you will become dehydrated so it’s important that you drink the right amount of fluid before, during and after driving or exercise.
Dehydration can reduce your performance. You can test if you’re dehydrated by looking at the colour of your urine. It should be pale, so if it’s dark then you could be dehydrated. There is a simple technique to work out how much fluid you lose during exercise or while driving, and how much you will need to drink to ensure you’re well hydrated. Weigh yourself before the session and then compare it with how much you weigh after the session. You need to drink around 1.5 litres of fluid for every kg that you lose.
If you don’t drink enough before the session, your core temperature will increase quicker and your heart will have to work harder than normal. To ensure you work at your best performance and prevent conditions such as heat stroke, keep yourself topped up with fluid throughout the day. You should drink around 5 to 7ml of fluid per kg of body mass at least four hours before you exercise to ensure you’re well hydrated. If you don’t urinate, or your urine is dark, then slowly drink more fluid around 2 hours before your session.
The amount of fluid you need to drink during execise can vary depending on the temperature outside, the amount you sweat and length of your session. Drinking sports drinks can be helpful as they contain a source of energy. The best way to know how much you need to drink during exercise is to weigh yourself before and after a session – aim to maintain your weight. If you’re driving or exercising for a long period of time, a sports drink can be helpful, such as Lucozade Sport (30 to 60g carbohydrate per hour). Experiment with timings and the amount of fluid before you race so that you know what works well for you.
Replacing the amount of fluid that you lose during exercise is very important, especially if you’re doing repeated bouts of exercise or driving. It’s also important that you replace the salt that you lose when sweating. You can have sports drinks, or water with a pinch of salt to help restore your fluid levels. Slowly drink 1.5 litres of fluid per kg of body mass lost. Don’t drink coffee or other caffeinated drinks or alcohol because they remove water from your body by increasing the amount of urine your kidneys produce.
What is the difference between hypotonic, isotonic and hypertonic sports drinks?
Hypotonic drinks have low carbohydrates (less than 4g per 100ml) and replace the fluids you lose during exercise. Isotonic drinks contain 4 to 8g of carbohydrate per 100ml and as well as helping to replace fluid, they also help top up your body’s carbohydrate stores. Hypertonic fluids have a high amount of carbohydrate (over 8g per 100ml). Your body absorbs them more slowly but it will really help to refuel your energy stores.