What is heat exhaustion?

Long periods in the sun can lead to heat exhaustion. Heat exhaustion is caused by a loss of salt and water from the body, usually through excessive sweating.

It develops slowly and usually happens to people who aren’t used to hot, humid weather. If you’re at a festival, a sports match or an outdoor event and it’s very hot, it’s easy to suffer from heat exhaustion.  Prevention is best, so always try to stay well hydrated by drinking plenty of water (but not too much, drink to thirst), wear light and loose-fitting clothing, a wide-brimmed sun hat, and sun cream. 

Try to keep out of the direct sun during the hottest part of the day, from 11am to 3pm. Heat exhaustion isn't always caused by weather and can be a consequence of the body producing more heat than it can lose during vigorous or endurance exercise. 

Some prescribed medications can make people more susceptible to heat illness (for example, Selective Serotonin Reuptake Inhibitors (SSRIs) like Sertraline and Tricyclic Antidepressants like Amitriptyline). Recreational drugs such as ecstasy can also affect a person's ability to regulate their temperature. It is important to spot and treat heat exhaustion, as it can lead to heatstroke.

Signs and symptoms

Look for:

• headache
• dizziness and confusion
• loss of appetite and feeling sick
• sweating with pale, clammy skin
• cramps in the arms, legs and stomach
• fast, weakening pulse and rapid breathing