What are the symptoms of dehydration? Signs to spot and how to prevent heat stroke as UK prepares for heatwave

Temperatures are forecast to exceed 40C in parts of the UK

Brits are being warned that an “exceptional” hot spell could lead to “widespread impacts” on people and infrastructure.

The Met Office has issued a red heat warning for the first time ever - as 41C temperatures are predicted for Heathrow Airport on Tuesday (19 July).

There could be “serious” health implications of the hot weather in the coming days, as a sweltering heatwave sweeps the UK.

The red weather warning will be in place for London, Manchester and as are as the Vale of York on Monday (18 July) and Tuesday.

Brits are being warned to be wary of the “serious” health implications of the hot weather (Composite: Kim Mogg / NationalWorld)

What is a red weather warning?

The Met Office is forecasting temperatures exceeding 40C for the first time.

It is currently predicting highs of 41C could be seen at Heathrow Airport on 19 July, which would make it the hottest day on record in the UK.

The current record is 38.7C seen in Cambridge in 2019.

A red heat warning means that the Met Office expects “extreme heat”.

A level four heat health alert has been issued by the UK Health Security Agency (UKHSA) for Monday and Tuesday.

It has declared the coming hot spell a “national emergency” and this is “reached when a heatwave is so severe and/or prolonged that its effects extend outside the health and social care system”.

At this level, illness and death may occur among the fit and healthy, and not just in high-risk groups.

People are being urged to take precautions in the warm weather and to be aware of the direct health effects of extreme heat, including heatstroke and dehydration.

What are the symptoms of dehydration?

Dehydration is a common symptom of extreme heat and occurs when the body loses more fluid than it is taking in.

When the normal water content of your body is reduced, this upsets the balance of salts and sugar in your body, affecting the way it functions. If left untreated, symptoms can worsen and become a more serious problem.

Early warning signs of dehydration include:

  • Feeling thirsty
  • Dark yellow and strong smelling urine
  • Feeling dizzy or lightheaded
  • Feeling tired
  • Dry mouth, lips and eyes
  • Urinating little and fewer than four times per day

A lack of fluids is the most common cause of dehydration, but it can occur more easily if you are suffering from heatstroke, have a high temperature of 38C or above, have diabetes, or you have been vomiting or have diarrhoea.

How can I treat dehydration?

If you are severely dehydrated your body needs to be replenished with the sugar, salts and minerals it lost.

Oral rehydration sachets are a good way to do this, which a pharmacist can recommend, or you can drink lots of water. Try to avoid large amounts of tea or coffee as these are high in caffeine.

If you feel too hot, it is advised that you move to a cool place, lie down with your feet slightly raised, and apply cold water to your skin to help bring your body temperature down.

You should call 999 or go to A&E if:

  • you are feeling unusually tired
  • you are confused and disorientated
  • any dizziness when you stand up doesn’t go away
  • you haven’t urinated for eight hours
  • your pulse is weak or rapid
  • you have fits (seizures)

These symptoms can be signs of serious dehydration and require urgent treatment.