What should you know about heat cramps and heat exhaustion?

Heat cramps usually involve sudden tightening in working muscles after sweating and exertion. Heat exhaustion can include excessive sweating, headache, dizziness, unusual tiredness, nausea, thirst, weakness, and cool or clammy skin. Dark urine may suggest significant fluid loss. A person can have cramps and heat exhaustion at the same time.

Heat intolerance is a tendency to feel unwell in warm conditions and is not the same as an acute heat illness. Heat exhaustion can worsen if exposure continues, so early action matters even when the person is still awake and able to speak.

Stop activity and move the person to shade or an air-conditioned space. Lay them down if dizzy, loosen clothing, cool the skin with wet cloths or a fan, and offer small sips of cool fluid if they are alert and able to swallow. Do not leave them alone, and do not give drinks to someone who is confused, vomiting repeatedly, or unable to swallow.

A cramping muscle can be gently stretched after exertion stops. Avoid returning to exercise until symptoms have fully settled and the person has recovered.

Call emergency services for confusion, loss of consciousness, seizure, severe breathing difficulty, or a very high body temperature. These can indicate heatstroke, which is life-threatening. Cool the person while waiting for help and follow the dispatcher’s instructions.

Seek urgent medical advice if symptoms do not improve promptly with cooling and fluids, or if there is persistent vomiting, worsening dizziness, marked weakness, or very little urine. Children, older adults, pregnant people, and those with long-term conditions may need earlier assessment.

How can I recognise heat illness early? Does my medication or health condition raise my risk? When can I safely return to work, sport, or outdoor activity after an episode?