Transcript Slide 1
Hydration It might surprise you to know that when you exercise you can lose up to a litre of fluid in an hour, although the amount lost varies from person to person and depends on how long and how hard you’re exercising. You mainly lose fluid through sweating and in the air that you breathe out. If you don’t keep your fluid levels topped up, you will quickly become dehydrated, which can affect your health and ability to continue exercising. Therefore, it’s important to make sure you get the right amount of fluid before, during and after exercise Click on a button below to learn more Before you Start Exercise During Exercise After Exercise Drinking To Much Sports Drinks Dehydration Hydration Sports Drinks The array of different sports drinks can be overwhelming and you could be forgiven for not knowing which to choose or whether they really offer any benefit. Most people doing moderate amounts of exercise won’t need them, but if you’re doing a lot of strenuous training, they may be useful. As well as replacing lost fluid, these drinks contain carbohydrates and electrolytes (sodium, potassium, magnesium and chloride). These provide fuel, help to keep you hydrated and simply make the drink taste better. There are three types of sports drink all of which contain various levels of fluid, electrolytes and carbohydrate. Which is most suitable? Isotonic - quickly replaces fluids lost by sweating and supplies a boost of carbohydrate. This drink is the choice for most athletes - middle and long distance running or team sports. Glucose is the body's preferred source of energy therefore it may be appropriate to consume Isotonic drinks where the carbohydrate source is glucose in a concentration of 6% to 8% - e.g. High Five, SiS Go, Boots Isotonic, Lucozade Sport. Hypotonic - quickly replaces fluids lost by sweating. Suitable for athletes who need fluid without the boost of carbohydrate e.g. jockeys and gymnasts. Hypertonic - used to supplement daily carbohydrate intake normally after exercise to top up muscle glycogen stores. In ultra distance events, high levels of energy are required and Hypertonic drinks can be taken during exercise to meet the energy demands. If used during exercise Hypertonic drinks need to be used in conjunction with Isotonic drinks to replace fluids. Created by: [email protected] Hydration Before You Start Exercise Making sure you’re well hydrated before exercising is very important, especially if you’re in a warm environment. If you’re dehydrated before you even start, your core temperature will rise faster and your heart will have to work harder than usual. This can have a negative effect on your performance and can even lead to serious conditions such as heat stroke. Provided you keep yourself topped up with fluid during the day, and you haven’t exercised for eight to 12 hours, you should be hydrated enough to exercise at any time of the day. Hydration During Exercise If you’re even just a little dehydrated, it can have a negative effect on your performance so it’s important to keep an eye on your fluid levels. It’s best to drink early on and at regular intervals while you’re exercising. The amount you need to drink will depend on how much you sweat and how long you exercise for. You can work out how much fluid you lose in a typical exercise session and how much you will need to drink during and afterwards by weighing yourself after exercise (do this before passing urine). Compare this with how much you weighed before exercising (weigh yourself after passing urine). For every kilogram of body weight you lose, you need to drink about 1.5 litres (l) of fluid. If you’re exercising for less than an hour, water is all you need to keep you hydrated. If you’re exercising for longer than an hour, sports drinks that contain carbohydrate or even just squash, can help you keep going as the sugar provides extra fuel. If you’re training for a race or other event, it’s a good idea to practise drinking while you exercise. This will help you get to know how much fluid you need and when to drink. It’s important that you don’t wait until you feel thirsty before you drink – by then, it’s too late and you will already be dehydrated. Hydration After Exercise Once all the hard work is over, no doubt you will be ready for something to drink. Not only will this be refreshing, but it’s important for restoring your fluid levels, which helps your muscles to recover. Remember that you need to be replacing the fluid you lose while you’re exercising – don’t wait until you finish. The sooner you start to replace the fluid, the sooner you will recover. Sports drinks or water with a pinch of salt can help to restore your fluid levels. Try having something salty to eat – it might sound odd but this will naturally make you thirstier so you will drink more and therefore rehydrate more quickly. Don’t drink alcohol or caffeinated drinks straight after exercise because they are diuretics, which means they remove water from your body by increasing the amount of urine your kidneys produce. Effects of Drinking To Much Although you may be so parched after exercise that you feel you could drink gallons of water, it’s important to bear in mind that drinking too much can be harmful and could cause a rare condition called hyponatremia. This is when excess water dilutes the salts in your body and your cells swell up, which can cause a number of health problems. Symptoms of hyponatremia include feeling confused or disorientated, a headache, feeling sick, vomiting and muscle cramps. In a worst case scenario, severe hyponatremia can lead to a coma, seizures (fits) and even death. Polly Kerr, Bupa Health Information Team, October 2012. http://www.bupa.co.uk/individuals/health-information/directory/h/hydrationexercise#textBlock225885 Dehydration Effects of Increasing Dehydration on Physical Performance Body Water Loss Effects 0.5% Increased strain on the heart 1% Reduced aerobic endurance 3% Reduced muscular endurance The Performance Zone by Dr John Ivy 4% Reduced muscular strength, heat cramps 5% Heat exhaustion, cramping and fatigue 6% Heatstroke , coma What Does Your Urine Say About You? *1Kg= 1 lL