Why does heat exhaustion cause nausea?

In heat, the body directs more blood toward the skin to release warmth. Digestion may slow when less blood is available to the stomach and intestines, especially during exercise. Sweating can also deplete fluid and salts, which may bring dizziness, headache, weakness and a queasy feeling. Nausea is a common presentation of Heat Exhaustion, although nausea can also arise from infections, medicines and many other causes.

Stop the activity, get into a cool place and rest. Use a fan, cool wet cloths or a cool shower if this is comfortable. If you can swallow without vomiting, begin with tiny, regular sips of a cool drink rather than a large amount at once. Avoid alcohol, heavy meals and further heat exposure. If nausea passes, choose light food only when you feel ready.

Call emergency services if there is confusion, fainting, seizure, collapse, severe weakness, or altered behaviour after heat exposure. Get urgent medical advice if repeated vomiting stops you from drinking, you cannot keep fluids down, abdominal pain is severe, or symptoms fail to improve with cooling and rest. Children, older adults and people with chronic illness may need assessment sooner.

Ask whether your symptoms and activity pattern fit heat illness, and whether any medicines could contribute to dehydration or nausea. A clinician can also advise on safe fluids and a gradual return to outdoor activity.