What should you know about humidity exhaustion?

Sweating cools the body when it evaporates. In humid air, evaporation is slower, so the body may work harder to release heat. You may notice tiredness, thirst, headache, dizziness, nausea, heavy sweating or reduced concentration. Dehydration can add to the problem. Fatigue that continues indoors or on cooler days has other possible explanations, including anaemia, infection, poor sleep, burnout, kidney disease or a nutritional condition.

Stop exertion, move to a cool or shaded place, loosen extra clothing and sip fluids. Use cool wet cloths or a fan, and ask someone to stay with you if you feel faint. Avoid alcohol while recovering because it can worsen fluid loss. Resume activity gradually only after you feel well. If tiredness returns often, keep a record of sleep, heat exposure, medicines, food and associated symptoms for a clinician.

Seek emergency help for confusion, collapse, seizure, severe breathlessness, chest pain, inability to drink or a person who is very hot and not improving after cooling. Arrange medical review for persistent fatigue, faintness, unexplained weight change, fever, breathlessness on ordinary activity or symptoms that occur without heat exposure. Do not assume ongoing exhaustion is caused by humidity.

Ask whether your symptoms fit heat strain or dehydration, whether medicines or sleep could contribute, and whether testing for anaemia, infection or another condition is appropriate.