Why do you feel more lethargic in hotter weather?

Is there an explanation for why many of us feel more tired during the summer? And is there a way of preventing this from happening?

Why do you feel more lethargic in hotter weather?
© unsplash
Why do you feel more lethargic in hotter weather?

Have you ever noticed whether it was when you were on vacation in some hot tropical holiday destination or during British heatwaves (as is currently the case!) that you feel more tired?

Discover our latest podcast

It's almost as if the hotter the weather the more prone we become to taking naps or the harder it gets to get up in the morning. Well, according to science there is a perfectly reasonable explanation for this peculiar phenomenon.

Temperature regulation and dehydration

Dr, Aimée Brame, Consultant Physician at London Bridge Hospital, explains that the main reason for feeling more tired during the warmer months of the year boils down to the body's effort to regulate one's own temperature. She says:

It takes a lot of energy to maintain the temperature of the body, keeping cool takes effort. Maintaining a constant internal temperature is vital for normal body function.

And adds:

The brain detects a rise in blood temperature and causes the body to sweat and blood vessels to dilate to lose heat—these processes are active and require energy.

Dr. Brame goes on to explain that excess sweating caused by high temperatures outside result in higher chances of dehydration, which in turn can leave you feeling quite drowsy:

In addition to fluid loss, the loss of essential salts and electrolytes such as potassium, calcium and magnesium can also make you feel worn out.

Another common reason why we tend to feel much more tired in the summer is that people often have a harder time falling (and staying) asleep when we are uncomfortably sweaty at night. Naturally, poor sleep the night before makes for a lethargic day to be had the following day.

How to avoid overheating?

So what should be done to avoid this from happening? Perhaps the most obvious advice is to avoid overexposure to the sun by staying in the shade and cool areas as much as possible. Specifically, avoiding the sun between 11 am and 3pm—when it's at its strongest—is a good way of keeping cool.

Dr. Brame also suggests taking cold showers and making sure you are drinking sufficient amounts of water throughout the day. Finally, snacking on fruits and vegetables and avoiding diuretics, such as coffee and alcohol, are key to staying awake, alert and focused throughout the day.

Sleep deprivation: This is what happens to your body when you are sleep-deprived Sleep deprivation: This is what happens to your body when you are sleep-deprived