What should you know about shivering after heat exhaustion?

After heat exposure, sweating and dehydration can disturb the body’s temperature control. As you cool down, blood flow and muscle activity may change, producing shivering even when the skin feels warm. Heat exhaustion commonly includes heavy sweating, weakness, headache, dizziness, thirst, nausea, and cool or clammy skin. Dark urine can suggest that you need more fluid, although it does not establish the cause. Shivering should gradually settle as you move to a cooler place and rehydrate. It is not a sign that you should return to heat or exercise.

Stop activity and rest in a shaded or air-conditioned place. Loosen tight clothing and cool the skin with a fan, cool cloths, or a lukewarm shower. If you are awake, able to swallow, and not vomiting, take frequent small sips of water or an oral rehydration drink. Avoid alcohol. Have someone stay with you and note whether your alertness, sweating, dizziness, and shivering improve. Do not force fluids if you are confused or drowsy.

Call emergency services for confusion, collapse, seizure, severe breathlessness, inability to drink, or a worsening headache. Urgent assessment is also needed if shivering persists despite cooling and fluids, if you become very hot, or if symptoms return after seeming to improve. Heat illness can progress quickly, and dehydration may need medical treatment.

Could this be ongoing heat illness or dehydration? How should I replace fluids? When can I safely resume work or exercise in heat? Do my medicines or health conditions increase my risk?