How to stay safe during hot weather and recognize heat exhaustion

Periods of hot weather can affect anyone, but some people run a greater risk of serious harm.

Experts recommend that those who may be more vulnerable - such as older people and babies and young children - should take extra precautions.

As the body gets hotter, blood vessels open up. This lowers your blood pressure and makes your heart work harder to push the blood around the body.

This process can cause mild symptoms such as an itchy heat rash or swollen feet.

At the same time, sweating leads to the loss of fluids and salt and, crucially, the balance between them in the body changes.

This, combined with the lowered blood pressure, can lead to heat exhaustion. Symptoms include:

dizziness

nausea

fainting

confusion

muscle cramps

headaches

heavy sweating

tiredness

If blood pressure drops too far, the risk of heart attacks rises.

Our bodies strive to keep a core temperature of about 37C whether we are in a snowstorm or a heatwave.

That is the temperature at which our bodies have evolved to work.

But as the weather gets hotter, it is harder for the body to keep its core temperature down.

It opens more blood vessels near the skin to lose heat to our surroundings and starts sweating.

As the sweat evaporates, it dramatically increases the heat lost from the skin.

The UK Health Security Agency (UKHSA) recommends looking out for those who may struggle to keep cool, such as older people, those with underlying conditions and those who live alone.

Other advice includes:

staying cool indoors by closing curtains on rooms that face the sun

drinking plenty of fluids and avoiding too much alcohol

keeping out of the sun between 11:00 and 15:00 when the sun's rays are strongest

staying in the shade, using sunscreen with a high SPF and UVA rating, and wearing a wide-brimmed hat

avoiding physical exercise in the hottest part of the day

carrying water with you if travelling

Anyone tempted to cool off in rivers and open water should consult local warning signs and consider any hidden dangers, external.

No one - especially babies, young children and animals - should ever be left in a locked vehicle.

If you see someone you think has heat exhaustion, the NHS says you should:, external

move them to a cool place

get them to lie down and raise their feet slightly

get them to drink plenty of water - sports or rehydration drinks are also OK

cool their skin - spray or sponge them with cool water and fan them. Cold packs around the armpits or neck are also good

If they can be cooled down within half an hour, then heat exhaustion is not normally serious.

However, if they do not recover within 30 minutes, then they are at risk of heatstroke.

This is a medical emergency and you should call 999 immediately.

People with heatstroke may stop sweating even though they are too hot. Their temperature could go over 40C and they might have seizures or lose consciousness.

People who are older or have some long-term conditions - such as heart disease - are sometimes less able to cope with the strain heat puts on the body.

Diabetes can make the body lose water more quickly and some complications of the disease can alter blood vessels and the ability to sweat.

Children and those who are less mobile may also be more vulnerable. Brain diseases, such as dementia, can also leave people unaware of the heat or unable to do anything about it.

People who are homeless will also be more exposed to the sun. Those living in top-floor flats will also face higher temperatures.

During 2022 - which saw the highest recorded temperature in England at 40.3C - there were an estimated 2,985 so-called "excess deaths" as a result of the heat, external, the most recorded in any given year.

There were an estimated 1,311 heat-associated deaths, external during summer 2024, and an estimated 1,504, external during summer 2025.

Most heat-related excess deaths are due to heart attacks and strokes caused by the strain of trying to keep body temperatures stable.

The higher death rate starts to kick in once the thermometer passes 25C-26C.

However, evidence suggests the deaths tend to be caused by higher temperatures in spring or early summer rather than during "peak summer".

This could be because we start to change our day-to-day behaviour as summer progresses and we get more used to dealing with the heat.

The evidence from previous heatwaves is the increase in deaths happens very quickly - within the first 24 hours of a heatwave.