Hydration on hot days – who should take electrolytes?

As the temperature outside rises, the body has to work harder to maintain a normal body temperature. On hot days, sweat production increases, and along with it we lose not only water but also some minerals. Even mild dehydration can affect how you feel, your concentration and your physical performance. That is why staying properly hydrated is one of the most important aspects of looking after your health in summer. Contrary to popular belief, however, it is not simply a matter of drinking as much water as possible. Consistency, diet and tailoring fluid intake to individual needs are also important.

1. Why is hydration so important?
2. How much fluid should you drink?
3. Is water the only way to stay hydrated?
4. Physical activity and hydration
5. Do you need to replenish electrolytes?
6. Which drinks are best avoided?
7. Practical ways to stay better hydrated
8. Who should take particular care to stay hydrated?
9. FAQ
10. Summary

Why is hydration so important?

Water makes up more than half of an adult’s body weight and plays a part in almost all the processes taking place in the body. Among other things, it is responsible for transporting nutrients, regulating body temperature, removing waste products, and ensuring the proper functioning of the muscles and brain.

During hot weather, the body cools itself through sweating. This is a natural protective mechanism, but it leads to increased fluid loss. If fluids are not regularly replenished, this can lead to tiredness, headaches, a dry mouth, dizziness or impaired concentration. For people who are physically active or work outdoors, the need for fluids is even greater.

How much fluid should you drink?

There is no single, universal amount of water that is suitable for everyone. Your fluid requirements depend on your age, body weight, ambient temperature, level of physical activity and state of health. On hot days, most people need more fluids than usual, as fluid loss through sweating increases significantly. The best approach is to drink small amounts of water regularly throughout the day. It is not a good idea to wait until you feel very thirsty, as this is a sign that your body is already starting to become dehydrated. The colour of your urine is also a good indicator of hydration – a pale yellow colour usually indicates that you are adequately hydrated.

Is water the only way to stay hydrated?

Although water is the best choice, it is not the only source of fluids. Milk, herbal teas, coffee and soups can also be included in your daily fluid intake. On hot days, unsweetened water-based drinks with added mint, lemon or slices of cucumber also work well, as they can make it easier to drink regularly. We mustn’t forget about foods rich in water. Watermelon, melon, strawberries, cucumbers, tomatoes, courgettes and lettuce provide significant amounts of fluids, as well as vitamins and minerals. As a result, they help keep the body hydrated and make for light meals that are ideal in hot weather.

Physical activity and hydration

In summer, many people continue to go running, cycling or training outdoors. In such conditions, fluid loss can be very significant, especially during intense exercise or in high humidity.

Before starting any activity, it is important to ensure you are properly hydrated, and during longer training sessions, you should replenish fluids regularly. After finishing your workout, you should also remember to drink an adequate amount of fluid. For training sessions lasting around an hour or less, plain water is usually more than enough. During prolonged and intense exercise, particularly when combined with heavy sweating, drinks containing carbohydrates and electrolytes can be helpful.

Do you need to replenish electrolytes?

Through sweat, the body loses not only water, but also sodium and smaller amounts of other minerals. In most cases, healthy people replenish these through a daily, well-balanced diet. Additional electrolyte supplementation is not necessary during normal activity and moderate sweating.

The situation is different during training sessions lasting many hours, sporting competitions or work in very high temperatures. In such cases, drinks containing electrolytes can help to replenish losses associated with intense sweating. The most important thing, however, is to tailor their use to your actual needs, rather than consuming them preventatively every day.

Electrolytes and their functions

Which drinks are best avoided?

In summer, sweet fizzy drinks, colourful lemonades and ice-cold energy drinks are particularly tempting. Although they provide fluids, they often contain large amounts of sugar, which increases the calorie content of your diet and does not support daily hydration. It’s also worth exercising caution with alcohol. It can increase fluid loss and disrupt the body’s ability to regulate its temperature. If alcohol is consumed during summer gatherings, it’s a good idea to remember to drink water at the same time.

Practical ways to stay better hydrated

Drinking regularly is much easier once you’ve established a simple habit. It’s a good idea to carry a bottle of water with you, whether at work, out for a walk or travelling. It can also be helpful to start each meal with a few sips of water and to drink a glass as soon as you wake up. Those who aren’t keen on the taste of plain water can add slices of citrus fruit, fresh fruit, mint leaves or lemon balm. This makes the drink more appealing without the need to add sugar. Chilling the water in the fridge is also a good idea, although there’s no need for it to be very cold.

Who should take particular care to stay hydrated?

Young children, older people, and pregnant and breastfeeding women are more at risk of dehydration. In children, the mechanisms regulating body temperature are not yet fully developed, whilst older people often have a reduced sense of thirst. People doing heavy physical work and athletes training outdoors also need to take extra care. In these groups, it is important to pay particular attention to drinking fluids regularly, avoiding direct sunlight during the hottest part of the day, and choosing appropriate clothing.

"During hot weather, regularity is key. The body copes much better with small amounts of fluid drunk throughout the day than with replenishing large amounts of water only when a strong sense of thirst arises. In most cases, plain water remains the best choice, whilst drinks containing electrolytes are mainly needed during prolonged and intense exercise or when working in high temperatures." Łukasz Domeracki – Dietitian

FAQ

How much water should you drink in hot weather?

There is no single, universal amount that suits everyone. Fluid requirements depend, amongst other things, on the ambient temperature, age, body weight, state of health and level of physical activity. On hot days, most people need more fluids than usual.

Do coffee and tea dehydrate the body?

No. For people who regularly consume caffeine, coffee and tea can be counted towards their daily fluid intake. However, it is worth remembering that water remains the primary hydrating drink.

How can you tell if your body is well hydrated?

One simple indicator is the colour of your urine. A pale yellow colour usually indicates adequate hydration, whilst darker urine may suggest a need to increase your fluid intake.

Do you need to drink electrolyte drinks during hot weather?

Not always. For most healthy people, electrolytes are replenished through their daily diet. Electrolyte drinks can be helpful during prolonged, intense exercise or when working in high temperatures combined with heavy sweating.

Which foods help maintain proper hydration?

As well as water, it’s worth eating foods rich in water, such as watermelon, melon, strawberries, cucumbers, tomatoes, lettuce and courgettes. These provide an additional source of fluids, as well as vitamins and minerals.

Does feeling thirsty mean that the body is already dehydrated?

Thirst is a sign that the body needs fluids. It is therefore better to drink regularly throughout the day, rather than waiting until you feel a strong urge to drink.

Does alcohol help quench your thirst on hot days?

No. Alcohol can increase fluid loss and make it harder for the body to regulate its temperature. If you do drink alcohol, it’s important to remember to drink water regularly at the same time.

Who is most at risk of dehydration during hot weather?

Young children, the elderly, pregnant and breastfeeding women, as well as those doing heavy physical work and athletes training outdoors, should take particular care. People in these groups should make a special effort to drink fluids regularly and avoid being out in the sun during the hottest part of the day.

Summary

Staying well-hydrated is one of the simplest ways to support your body during hot weather. Drinking water regularly, eating foods rich in water, and adjusting your fluid intake to suit the temperature and your level of physical activity help to maintain your well-being and ensure your body functions properly. It is not worth waiting until you feel very thirsty – it is much better to get into the habit of drinking fluids regularly throughout the day. Combined with a light diet, limiting alcohol intake and sensible planning of physical activity, this allows you to get through even the hottest days more safely and comfortably.

Sources:

• https://www.healthline.com/health/nutrition/how-to-stay-hydrated-in-heat
• https://pmc.ncbi.nlm.nih.gov/articles/PMC12787638/