Why You Feel More Tired in Hot Weather — and What You Can Do About It

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1. Your body is working overtime to keep you cool

2. Dehydration can leave you feeling drained

3. Hot nights can mean poorer sleep

4. Exercise can feel harder in the heat

5. You may be losing more than just water

6. Heat can affect your appetite and routine

7. How to feel more energised in hot weather

8. When tiredness could be something more serious

9. The bottom line

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Ever notice that a hot summer day can leave you feeling completely wiped out—even when you haven’t done much?

You’re not imagining it. Hot weather can make you feel more sluggish, sleepy and generally low on energy because your body has to work harder to keep your temperature within a safe range.

From dehydration and disrupted sleep to the extra effort involved in cooling yourself down, there are several reasons why summer heat can leave you feeling drained. The good news? A few simple habits can help you feel more comfortable and energised.

Your body is working overtime to keep you cool

Your body naturally tries to maintain a stable internal temperature. When the temperature outside rises, your body has to work harder to release excess heat.

One of the main ways it does this is by sending more blood towards the skin, allowing heat to escape. You also sweat, and as that sweat evaporates, it helps cool you down.

All of this requires energy. So even if you’re relaxing in the garden or sitting at your desk, your body may be putting in more work than usual.

That can leave you feeling tired, particularly during very hot or humid weather.

Dehydration can leave you feeling drained

Sweating is essential for cooling your body, but it also means you lose fluids.

If you don't replace those fluids, even mild dehydration can contribute to tiredness, headaches, dizziness and difficulty concentrating. You may also feel less motivated to exercise or carry out everyday activities.

Rather than waiting until you feel extremely thirsty, try drinking regularly throughout the day. Water is usually the best choice for everyday hydration.

You can also get fluids from foods with a high water content, including:

• Watermelon

• Strawberries

• Cucumber

• Tomatoes

• Oranges

• Peaches

  
  

If you’ve been sweating heavily for a prolonged period, particularly during exercise, replacing electrolytes may also be helpful.

Hot nights can mean poorer sleep

One of the biggest reasons you might feel exhausted during a heatwave actually happens while you’re asleep.

Your body temperature naturally changes as part of your sleep cycle. When your bedroom is excessively warm, it can become harder to fall asleep and stay asleep comfortably.

You might wake up more frequently, sleep less deeply or simply feel as though you haven't had a refreshing night's sleep.

Try keeping your bedroom as cool and well ventilated as possible. Lightweight bedding, breathable sleepwear and closing curtains or blinds during the hottest part of the day can also help.

Exercise can feel harder in the heat

If your usual workout suddenly feels much more difficult during summer, heat could be partly responsible.

During exercise, your body needs to supply your muscles with oxygen while also working to cool itself. In hot conditions, this puts additional strain on your cardiovascular system.

You may notice that your heart rate feels higher, you sweat more or you become tired more quickly than usual.

That doesn't necessarily mean you're getting less fit. It simply means your body is dealing with an additional challenge.

Consider exercising early in the morning or later in the evening when temperatures are lower, and reduce the intensity when necessary.

You may be losing more than just water

Heavy sweating doesn't only result in fluid loss. Sweat also contains electrolytes, including sodium.

For most people doing normal day-to-day activities, a balanced diet and regular fluid intake are enough to replace what is lost. However, prolonged exercise or significant sweating can increase your electrolyte losses.

This is one reason you might feel particularly depleted after spending hours exercising, working outdoors or being active in very hot conditions.

Heat can affect your appetite and routine

Summer often changes our normal habits, too.

You might eat lighter meals, stay up later, travel more, drink more alcohol or spend longer outdoors. While none of these things is necessarily a problem on its own, changes to your usual routine can contribute to feeling tired.

Rather than trying to maintain a perfect routine, focus on the basics: regular meals, plenty of fluids, enough sleep and sensible breaks from the heat.

How to feel more energised in hot weather

You don't need to overhaul your entire lifestyle to cope better with summer heat.

Try these simple strategies:

Stay hydrated. Keep water nearby and drink regularly throughout the day.

Eat regularly. Choose balanced meals containing protein, carbohydrates, healthy fats and plenty of fruit and vegetables.

Take breaks from the heat. Spend time somewhere cool or shaded, particularly during the hottest part of the day.

Adjust your workouts. Exercise at cooler times and don't be afraid to reduce the intensity.

Protect your sleep. Keep your bedroom cool and comfortable wherever possible.

Listen to your body. Feeling more tired than usual during hot weather is a good reason to slow down and give yourself time to recover.

When tiredness could be something more serious

Although feeling tired in hot weather is common, extreme symptoms shouldn't be ignored.

If you develop severe weakness, confusion, fainting, significant dizziness or other concerning symptoms while exposed to heat, move somewhere cool and seek appropriate medical help. Heat-related illness can become serious, particularly during periods of extreme temperatures.

The bottom line

Feeling more tired when it's hot isn't simply a lack of motivation. Your body is constantly working to regulate its temperature, and heat can affect hydration, sleep, exercise performance and your normal daily routine.

The best approach is to work with your body rather than against it. Drink regularly, prioritise sleep, eat well, take breaks from the heat and adjust your activity levels when temperatures rise.

So the next time a hot summer afternoon leaves you ready for a nap, don't feel guilty about taking it easy. Your body might genuinely be asking for a little extra recovery time.