Why does hot weather make you tired?

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Health Advisor

15 July 2016

The weather and your energy levels

Just when we’d like our energy levels to be at their maximum so we can get out and about and enjoy the good weather, many of us find that instead our energy levels drop suddenly as the temperature warms up. 

We often begin to feel sluggish, lethargic and sleepy during hot weather, making us less inclined to get up and about. For some, hot weather even causes irritability and grumpiness!

This is rarely any cause for concern and can be easily remedied, but if you find that you are experiencing other symptoms such as dizziness, nausea, dark coloured urine and confusion, you may be suffering from heat exhaustion – a more serious condition that requires swift action.


The main cause of fatigue during hot weather is simply dehydration. When temperatures increase many of us forget to increase our water intake along with it – and this isn’t helped by the fact that many of us aren’t drinking enough water to start with.

This is also exacerbated by the fact that during sunny weather, many of us treat ourselves to cocktails, wine and cold beers in the sun with friends and family. Unfortunately, these actually dehydrate you faster than not drinking anything at all!

Water is vital for the metabolism of energy from food, so without it we struggle to make the most of the food we’re eating. Water is also important for carrying oxygen and nutrients around the body, and without these resources, our muscles and brain will begin to slow down, making us feel sleepy and sluggish.

When we sweat, we also lose vital electrolytes, which are important for a number of functions, including muscle and brain function.

Severe dehydration and loss of electrolytes are major contributing factors to heat exhaustion – so make sure to increase your water intake before this develops. This can be tricky for some, so for some advice on increasing your water intake, read our tips on how to avoid dehydration this summer.

Lack of sleep

It is surprising how often people seem to forget that tiredness is a direct result of a lack of sleep. This is common when temperatures stay warm overnight, as many of us struggle to get a good night’s sleep while our rooms are stuffy and hot. We begin to sweat, we toss and turn to get comfortable and we wake up repeatedly through the night. 

To help this, try switching to a lighter duvet or even a duvet cover with no duvet inside. Changing your sheets from synthetic material to cotton will also help. For more tips on alleviating this problem, read our blog post on 7 tips to keep cool at night.


If you need a helping hand, try Dormeasan, a natural sleep remedy containing Valerian and Hops that helps ease you into your natural sleep cycle.


Stress is a factor that is often overlooked. Summertime can bring new stresses to our lives: the kids are at home all day instead of in school, demanding attention and entertainment; family holidays bring financial worries, plus the stress of organising the holiday and getting everyone packed and ready; and the general disruption to routine that summer tends to bring is enough to unsettle our minds and cause stress. 

Stress causes our digestive system to slow down, meaning we aren’t absorbing as many nutrients from our food as usual. This makes it harder to metabolise energy, and it also means we can become deficient in the vitamins and minerals that we need to keep our bodies working and our energy levels up. Stress keeps our minds busy and burns up extra energy to prepare us for the fight or flight response, which can quickly leave us feeling drained.

Throughout the summer months, taking a stress herb like such as AvenaCalm can help reduce the symptoms of stress and keep your mind calm. If you need something a bit stronger, for sudden onsets of stress, try our Stress Relief Daytime.

What else can you do to combat tiredness?

There are a number of things that you can do to boost your energy levels, regardless of the cause of your tiredness (though addressing the root cause as well will boost these beneficial effects).

Make sure to eat plenty of energy-rich foods, like complex carbohydrates –brown rice, sweet potatoes, quinoa and legumes – chia seeds, leafy greens (such as kale and spinach) and nuts. For some more advice, head to our article on the foods to eat for fatigue.

For overall tiredness, we recommend our Balance Mineral Drink. It helps to rectify pH imbalances in the gut (caused by stress-eating, overindulgence of alcohol, or consumption of sugary and acidic foods), to maximise your absorption of essential nutrients. It also contains zinc, potassium, calcium and magnesium to replace the electrolytes lost through dehydration – electrolytes that are vital for energy, muscle function and the nervous system

Cool down with homemade ice cream!

This banana and pistachio 'nice' cream is vegan, easy to make and perfect for warm summer days.

Get the recipe

What we recommend

Try Balance Mineral drink to restore minerals, reduce fatigue and rehydrate after a day in the sun.

Learn more

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