24 July 2014
We have been experiencing some fantastic and prolonged warm weather. Often too rare in the UK, so no doubt everyone has been outside making the most of the sunshine and getting an important vitamin D top while doing so.
Although the warm weather is great to see and enjoy, it does bring some added challenges that need to be addressed for; not only during exercise, to ensure we stay healthy, fit and able to enjoy the weather all summer. When the temperature rises it places extra strain on the body and we begin to sweat at lower levels of exertion than we would at lower temperatures. There is also the chance of sweating through the day as we try to keep cool during our busy lives, however everyone will experience an increased water loss due to the evaporation effect while breathing.
The result of all this is increased water loss and so increased risk of dehydration. Evidence shows that a mere 2% dehydration of the body can decrease performance by 10%. As fluid is lost from the body the blood becomes more viscous and is harder for the heart to pump, which combined with decreased blood volume means more strain on your heart. To ensure optimum health as well as performance it is essential to stay hydrated. When participating in long endurance exercise or in very hot or humid conditions, it is also necessary to address electrolyte loss as these are excreted in sweat which can cause muscle cramping as well as altering the fluid balance within the body.
Aim to avoid dehydration by acting in advance and carrying a bottle with you that you can sip from and replenish all day, this will help keep your fluid levels up and avoid downing a litre in one go. We should generally aim to consume two litres of pure water a day, plus replenishing extra losses caused by sweating on top of that. Hard exercise in high heat and humidity can cause water loss by sweating of up to three litres an hour. This rapid loss will quickly impact on the bodys ability to perform, so extra water must be taken on during the exercise. This can take some getting used to and you don’t want to make yourself sick from drinking too much, so start with small amounts frequently. The body can be trained to consume larger amounts up to 500ml at a time without negative consequences. A useful guide to water loss can be to weigh yourself before your exercise session and again at the end (do this in minimal/fresh clothing to avoid the weight of sweat in the clothes), as a litre of water weighs one kilo you then need to consume a litre of water for every kilo of weight loss.
If water and mineral loss is substantial through either prolonged sweating at lower effort levels or heavy sweating at high effort levels, then an electrolyte solution should be used to rehydrate the body. A hypotonic solution is best for rehydration as it achieves a quicker uptake of water into the body. Isotonic solutions will replace fluid and salts at a slower rate and contain varying amounts of carbohydrate. The carbohydrates can help us recover from exercise or help keep the body fuelled during exercise and improve performance, but be aware of the extra calories they contain and that many of these types of drinks contain a lot of simple sugars.
Bristol Gym