Heatwave: level four alert

A level four alert is the highest heatwave alert in Britain, and is an emergency situation. It is raised when a heatwave is severe and/or prolonged, as the hot weather can cause problems.

At level four, the health risks from a heatwave can affect fit and healthy people, not just those in high-risk groups such as the elderly, the very young and people with chronic medical conditions.

The more prolonged a heatwave is, the greater the potential risk to our health, especially for those in high-risk groups.

If a level four alert is declared, follow the health information given during a level three alert. Check that anyone around you who is in a high-risk group is coping well with the heat.

During a heatwave, make sure you:

  • Listen to alerts on the radio and TV about keeping cool.
  • Avoid unnecessary travel.
  • Visit or phone people who are less able to look after themselves, such as older neighbours, relatives and friends, and people with health conditions or mobility problems.
  • Stay inside and in the coolest room in your home as much as possible, and splash yourself with cool water.
  • Keep rooms cool by using shade or reflective material outside the glass; if that's not possible, have light-coloured curtains and keep them closed (metallic blinds and dark curtains can make the room hotter).
  • Keep the windows closed while the room is cooler than it is outside, and, if it's safe, open the windows at night when the air is cooler than the room. 
  • Drink water or fruit juice regularly.
  • Avoid tea, coffee and alcohol, and if you do drink alcohol be sure to have water or other non-alcoholic drinks as well. 

People with heart problems, breathing difficulties or serious illnesses may find their symptoms become worse in hot weather. Make sure you have enough medicines in stock and take extra care to keep cool. 

Heat exhaustion and heatstroke

Severe heat can cause heat exhaustion or heatstroke. Keeping yourself cool will reduce the risk of illness. If you start to feel unwell, it's important to seek medical advice.

The symptoms of heat exhaustion include:

  • headaches
  • dizziness 
  • nausea and vomiting
  • muscle weakness or cramps 
  • pale skin 
  • high temperature

If this happens, move somewhere cool and drink plenty of water or fruit juice. If you can, take a lukewarm shower or sponge yourself down with cold water.

Heatstroke can develop if heat exhaustion is left untreated, but it can also occur suddenly and without warning.

Symptoms of heatstroke include:

  • headaches 
  • nausea 
  • intense thirst 
  • sleepiness 
  • hot, red and dry skin
  • a sudden rise in temperature
  • confusion 
  • aggression 
  • convulsions 
  • loss of consciousness

If you suspect that someone has heatstroke, call 999 immediately. Heatstroke can cause irreversible damage to your body, including the brain, or death.

Read more about heat exhaustion and heatstroke.

Page last reviewed: 03/07/2014

Next review due: 03/07/2016

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