The Importance of Hydration Whilst Exercising No ratings yet.

According to research, dehydration by just 2% of your body weight can noticeably impair your exercise performance. This negative effect gets even more severe when that figure hits 5% as the capacity for work decreases by about 30%.

With just small amounts of dehydration responsible for such massive amounts of loss in performance and productivity when out walking, hiking or partaking in any other activities, keeping hydrated should be at the top of your list of priorities when out and about.

Depending on the level of exertion when exercising, it is not uncommon to lose up to a litre of fluid per hour. This fluid is expelled during sweating as well as through the breathing process so even if you aren’t visibly sweating, you are still getting through a lot of essential fluid when the pace picks up.

Sweating is one of the body’s favoured physiological mechanisms for controlling body heat and keeping your core temperature down. This is done using a technique known as evaporative heat loss. However, once you become dehydrated you no longer have enough fluid to sweat out, severally hampering the body’s natural ability to keep your temperature under control and therefore affecting your performance.

This is all fluid that needs replacing to ensure you can work at your best and don’t succumb to premature fatigue when enjoying outdoor pursuits.

Signs of Dehydration

Waiting until you are thirsty before deciding to have a drink can be too late as by that point the dehydration process has already begun. For that reason it is best to be proactive in avoiding dehydration as the signs of dehydration tend to occur after the fact. However, if any of these symptoms arise, they could be considered good indicators that it’s time to rehydrate:

  • Dry mouth
  • Decreased urine volume and yellow or darker urine
  • Unexplained tiredness
  • Headaches

After that, the list gets pretty severe with symptoms such as dizziness, insomnia, rapid heart rate, confusion, shrivelled skin, spastic muscles and finally death by terminal dehydration amongst them. So in other words, don’t scrimp on the water!

Tips for Staying Hydrated

Obviously when the temperature rises and the sun comes out the need to stay hydrated increases due to the mounting risk of dehydration. However, even in the colder months dehydration is a serious issue and any activities that increase your heart rate or body temperature should be prepared for with a thorough hydration programme.

By following these tips, in the cooler months as well as the hot, you should be able to stave off dehydration for as long as possible, and therefore counteract and loss in performance associated with this condition:

  • Alongside hydration for exercise, it is recommended that women consume 2 litres of liquids a day, while men need 2.5 litres.
  • To keep everything ticking over this should be the minimum amount of water you drink each day, before factoring in exercise.
  • Ensure you begin your activity fully hydrated by consuming around 500 ml of water two hours before you begin.
  • When exercising drink early and at regular intervals to keep your fluid levels topped up, don’t want until you are thirsty or showing other signs of dehydration.
  • To rehydrate yourself after exercise, weigh yourself before and after a session and compare the weight. This will tell you how much fluid you lost. For every kilo of bodyweight lost, you will need to drink 1.5 litres of fluid.


While it is important to stay hydrated by taking in fluids, don’t go overboard and drink excessive amounts of water as this can lead to hyponatremia which isn’t good! However, by following these guidelines you should be able to reduce the risk of dehydration related performance impairment.

Image credit: Andy Hurvits (Flickr)

Please rate this

Share This:

Comments are closed.