We asked endurance athlete Shona Thomson for her tips on how to avoid dehydration and how you can spot the signs that you might be heading that way.
Why stay hydrated?
50-75% of the human body is made up of water. Ensuring that our bodies retain enough water to function properly and perform to the best level is essential to life. Children and the elderly are particularly susceptible to the effects of heat so need to take additional care in the hot weather to avoid dehydration.
How can a lack of water effect performance?
Exercise performance is impaired when an individual is dehydrated by as little as 2% of body weight. Losses in excess of 5% of body weight can decrease the capacity for work by about 30% (Armstrong et al. 1985; Craig and Cummings 1966; Maughan 1991; Sawka and Pandolf 1990).
What are the signs to watch out for that you are or may becoming dehydrated?
By the time you are thirsty you are probably already dehydrated. In addition to thirst, other signs include:
- Headache or nausea
- Low concentration
- Producing dark or less urine
How can you avoid dehydration?
There are several ways to help avoid dehydration:
- Avoid diuretic drinks when it's hot such as alcohol, tea and coffee.
- Sip water regularly throughout the day. An adult should aim to drink around 2 litres of water - more if you are participating in exercise.
- Add electrolytes to your water to help replace lost salts and minerals.
- Try to avoid exercising in the midday heat, instead plan your activity for the morning or evening when you're less likely to suffer heatstroke.
- Dress for the weather so that you are not sweating more than you need to. Wear light, wicking fabrics when it is hot and the correct layering system when it is cold.
How much water should I drink?
The European Food Safety Authority recommends that women should drink about 1.6 litres of fluid and men should drink about 2 litres of fluid per day. That's about eight glasses for a woman, and 10 glasses each for a man. However, the amount a person needs to drink to avoid getting dehydrated will vary depending on a range of factors, including their size, the temperature and how active they are. So, for example, if you're exercising hard in hot weather you'll need to a lot drink more.
How Do I know when I've drunk too much?
Perhaps talk about "drink to thirst" which hopes to persuade athletes not to over hydrate with the potentially fatal consequence of diluting your sodium level, causing hyponatraemia. The symptoms of over hydration are similar to those of dehydration and in very severe cases can lead to unconsciousness. The best advice is not to drink too much at once but sip as you go.
Should I drink Isotonic drinks?
Isotonic or sports drinks and other energy products contain similar concentrations of salt and sugar as the human body. They can be effective for athletes who lose water and electrolytes in training and competition. Due to the high energy content of the drinks, research suggests they are best suited for individuals who are competing in endurance events or doing exercise sessions of over 90 minutes.
Any extra tips for staying hydrated?
- Always carry a bottle with you
- Use a Camelbak or similar when exercising
- If you don't like the taste of water squeeze some lemon or lime into it
- Eat the right foods. Fruit and vegetables have a high water content so it's a good way to hydrate without having to drink too much water.
What to do if you feel dehydrated?
Drink fluids and rest for a while in a cool area. If the dehydration or over hydration is serious, please contact a medical professional.
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