Staying Hydrated When Exercising in The Heat

Staying hydrated doesn’t just mean drinking lots of water. After a run, workout or any other physical challenge, your body loses vital fluids and electrolytes and making sure you replenish those is essential to keep your energy levels up, brain firing and body performing.

The summer is finally bringing some wonderful weather, and whether you are a keen athlete or a casual sportsperson, staying hydrated is particularly important during these very hot days. 

Proper hydration not only helps perform at your best but also keeps you focused and feeling good overall. So, when it comes to picking the right drink, it’s good to know the different options and how they affect your body.

Hydration is key in athletic performance. When you work out, your body sweats to cool down. Sweating means you lose fluids and salts, and if you don’t replenish them, you risk dehydration. This results in fatigue, decreased cognitive function, and impaired physical performance. 

Of course, drinking water is essential, and as a rule of thumb its good to drink little and often when exercising. Aim for 500ml per hour of exercise, drinking 2 – 3 sips at a time every 7 to 10 minutes.

However, water alone might not be the best choice when you’re sweating more than usual. So, let’s look at ways to replace these lost fluids and electrolytes.

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Isotonic, hypotonic: which drink is best? #

For most athletes, an isotonic drink is the go-to option, especially during prolonged exercise. It’s usually well-tolerated, helps keep you optimally hydrated and provides a bit of energy to keep you going. 

An isotonic drink typically contains 4 – 8g of carbohydrates and electrolytes such as sodium, magnesium, and potassium. However, during high-intensity workouts, some athletes may find that they better tolerate a hypotonic drink. It contains less sugar (less than 4g of carbohydrates per 100ml) and, as a result, will lead to fewer gut troubles.

But when choosing your rehydration drinks, it is important to consider individual preferences and what your body can handle. The type of sugar used can affect how well you tolerate the drink. Some athletes may experience digestive issues with certain sugars or added ingredients such as flavouring agents, emulsifiers, or sweeteners. 

What works for some athletes may not be the best option for you, so it is important to experiment and find what suits you best. It is also worth noting that drinking smaller volumes more frequently will also minimise gut discomfort.

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Energy drinks, but made your way #

Now, what about energy drinks, you may ask? These are considered hypertonic drinks as they have a high content of carbohydrates, more than 8g/​100ml. While they may help in the recovery phase, they are not ideal for rehydration during the exercise because they can be hard to digest, and some may not contain much electrolytes.

It’s important to mention that hypertonic drinks are hard to digest when in action because their digestion requires oxygen and energy but the body prioritises movement over digestion. Most of the oxygen is utilised by the contracting muscles and digestion suffers.

In my opinion, nothing beats a homemade rehydration drink. It’s affordable, and you can customise it to fit your taste, needs, and tolerance. Here’s a recipe for you to try out:

Homemade Rehydration Drink Recipe #


  • 500ml of orange juice
  • 500ml of water
  • 14 teaspoon of salt


  • In a large container, combine the fruit juice.
  • Add 14 teaspoon of salt and mix well until the salt is dissolved.

With this recipe, you can tailor the drink to your liking while ensuring an appropriate carbohydrate level (4 – 8g per 100ml) for optimal hydration and comfort. Feel free to get creative with different fruit juices or cordials to make it tastier. After all, the more you enjoy the flavour, the more likely you’ll keep sipping and stay hydrated throughout your activities!

So, as with most nutritional advice, it’s all about personalisation and finding out what works for you and your body. Make sure to replenish your lost fluids and electrolytes after workouts, find something that your gut approves of, and make it tasty! 

Are you looking for nutritional advice to support your daily activities, lifestyle, or sporting goal? Click the button below to find out how we can help. 

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