Heat cramps at night

A calf, foot, thigh or abdominal muscle may tighten after a day spent in heat. Sweat loss, not drinking enough, or strenuous activity can alter the balance needed for normal muscle contraction. A warm bedroom, tight bedding or prolonged positioning may add discomfort, but recurring [Muscle Cramps](/symptoms/muscle-cramps/) also have causes unrelated to heat. Thirst, fatigue, dry mouth or [Muscle Aches](/symptoms/muscle-aches/) can point toward [Dehydration](/conditions/dehydration/).

Sit up safely, loosen bedding and gently lengthen the affected muscle: for a calf, straighten the leg and draw the toes toward you only as far as comfortable. Light massage and a cool room may help. Once the spasm eases, sip water slowly if you are alert and able to swallow. If a clinician has recommended it, [Oral Rehydration Therapy](/treatments/acute-and-urgent-care/oral-rehydration-therapy/) can replace fluid and salts. Avoid taking salt tablets or changing medicines without medical advice.

Arrange medical advice if cramps repeatedly wake you, last longer than expected, leave persistent weakness, or begin after a new medicine. Seek urgent help for confusion, fainting, seizure, breathing trouble, inability to drink, or severe overheating. These signs need prompt assessment rather than home treatment alone.

Ask whether your medicines, sleep environment, activity, fluid intake or medical history could be contributing. Keep a note of the time, muscle involved, heat exposure and any thirst, vomiting or urine changes.