03 December 2022

Common sense advice: Hydration/drinking while exercising

March 8, 2017

Even if you’re not exercising regularly you should be drinking 1.5 – 2 litres of water a day. Being even slightly dehydrated can seriously impact your performance and whilst water is the go-to choice for pure hydration, the extra elements in sports drinks will help keep you fresh and performing at your best whilst you exercise.


What are the difference between sports drinks and water?

Sports drinks contain carbohydrate (CHO) in the form of glucose, a nutrient that helps to replenish glycogen stores. Water also doesn’t provide the body with sodium (salt), a key element that helps the body hold on to fluid to hydrate.

How to make your own sports drink at home

Sports drinks can easily be made at home and are much cheaper than buying commercial brands. An isotonic drink could include:

  1. 200ml of fruit squash or juice
  2. 800ml water
  3. A pinch of salt

Types of sports drinks

Commercial sports drinks are designed to offer you a combination of the fluids and salts you lose during exercise, and they come with a variety of descriptions:

Hypotonic: Contain a small amount of CHO (under 4%). This is lower than your blood plasma concentration and so they are relatively easy to absorb and digest

Isotonic: Contain 4-8% CHO and also some salts, which is similar to the concentration of the blood plasma, so these are a better choice for replacing fluids rapidly during prolonged exercise.

Hypertonic: Include a higher concentration of CHO at over 8%, but do not include salts, and are sometimes used for refuelling glycogen stores post exercise. They can also be used during endurance events, but should be combined with isotonic drinks to ensure salts are also replenished.

Why is hydration important for exercise?

Around 70% of our body is made up of water and it is vital for every chemical reaction in the body. We need around 2-3 litres of water a day to transport nutrients, help with cellular enzyme activity and digestion of food, carry out waste and toxins and support brain function.

We lose water and body salts (largely sodium and chloride) through urine, but also when it evaporates as sweat during exercise. A loss of only 1-2% of our fluid body weight can impair performance by around 10-20% so it is vital to stay hydrated when you exercise.

How to stay hydrated

Some of the water we need will be extracted from our food, but day to day, we should be aiming to drink around 1.5 – 2 litres (roughly six large glasses) of water to replenish our stores.

This amount should be increased during exercise to prevent dehydration, and sports drinks which also contain carbohydrate (CHO) in the form of glucose can also be beneficial to help replenish glycogen stores.

Everyone loses fluids at different rates, and depending on their level of exertion, but as a general guide, always start any exercise session well-hydrated, then follow these guidelines according to the duration of your session:

  • Exercising under 30 minutes: No need to drink whilst exercising (unless it’s very warm), but re-hydrate with water after the session
  • Exercise from 30-60 minutes: As above, then re-hydrate post-training with a drink containing both water and CHO
  • Exercise 1-3 hours: Take a sports drink with you which combines water and CHO. Sip regularly throughout the session – aim for 30-60g CHO per hour. Continue to hydrate post training
  • Exercise 3hrs +: Choose a sports drink which combines water, CHO and some sodium/salts. Sip regularly taking on 30-60g CHO per hour and continue to drink post training

Checking hydration levels

There are two effective ways to check hydration levels when exercising. Weigh yourself both before and after a workout to see how much your weight has reduced. You should aim to restore levels to your original weight post-training (as a rough guide 1kg weight loss equates to around 1 litre of fluid).

Also check your urine colour; the darker it is, the more dehydrated you are (although if you are taking single nutrient supplements these can affect urine colour e.g. B Vitamins can turn urine fluorescent yellow.)

Tips for hydrating

  • Don’t allow yourself to become thirsty. If you are thirsty you are already dehydrated
  • Check your urine colour to monitor our levels of hydration
  • Sip small amounts frequently and practice drinking as part of your training (particularly if you are in training for a big event)
  • Try sports drinks before the event to ensure they agree with you. Most endurance events will tell you which ones they use
  • Don’t over-drink.  This can lead to hyponatremia, whereby plasma sodium levels are depleted to dangerous levels, resulting in confusion, lack of co-ordination and in some cases this can be fatal

For more nutrition and workout advice, visit Sportsshoes.com’s Training Hub

The Women’s Sports Magazine





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