What causes heat cramps?

Heat cramps often affect muscles used during exercise, such as the calves, thighs, arms, or abdomen. Heavy sweating removes water and electrolytes, while repeated contractions place extra demand on already tired muscles. Dehydration can make the situation worse. Muscle Cramps may begin during activity or soon afterward, with tight, painful knots that come and go. Muscle Aches can remain after the spasm settles. Hot, humid weather, protective clothing, long shifts, and sudden increases in exertion can all raise the strain on temperature control.

Stop the activity and move to a cooler place. Rest the affected muscle in a comfortable position and gently stretch it without bouncing or forcing the joint. Sip fluids; an electrolyte drink may be useful after heavy sweating when appropriate for your health. Cool the skin with shade, ventilation, or a damp cloth. Do not return to strenuous activity until cramps and other symptoms have settled. Oral Rehydration Therapy may be discussed with a clinician when fluid and electrolyte replacement is needed.

Get urgent help if cramps occur with confusion, fainting, seizures, severe weakness, hot dry skin, persistent vomiting, or difficulty breathing. These can signal a more serious heat illness. Arrange medical advice if spasms do not improve with rest and cooling, keep recurring, or occur without heat or exertion. People with heart, kidney, or fluid-balance conditions should seek tailored advice before increasing fluids or electrolytes.

Ask how much fluid is appropriate for your health, whether you need electrolyte replacement, and how to pace activity in hot weather. Ask which medicines or medical conditions could affect sweating, hydration, or muscle function, and how to recognise heat exhaustion early.