Dizziness from heat: what to know

In hot conditions, sweating removes water and salts, and widened skin blood vessels can affect blood pressure when you stand. Heat exhaustion commonly presents with heavy sweating, weakness, headache, nausea, cramps, and dizziness. Dehydration may add thirst, dry mouth, and reduced urine. Dizziness can also have an unrelated cause, such as benign paroxysmal positional vertigo, anaemia, iron deficiency anaemia, an irregular rhythm called atrial fibrillation, low blood sugar, or anxiety. The setting is a clue, not a diagnosis.

Stop activity and move to a cool, shaded or air-conditioned place. Sit or lie down, loosen extra clothing, and cool your skin with damp cloths or a fan. If you are awake and able to swallow, take small, frequent sips of water or an oral rehydration drink. Avoid returning to exercise until you feel fully recovered. Do not give drinks to someone who is confused, vomiting repeatedly, or unable to swallow safely. Arrange medical advice if symptoms do not improve with cooling and fluids.

Call emergency services for confusion, collapse, seizure, loss of consciousness, severe breathing difficulty, or inability to drink. Seek urgent care for worsening symptoms, repeated vomiting, very little urine, severe headache, chest pain, or an irregular heartbeat. A person who remains very unwell after moving to a cool place needs prompt assessment because heat illness can progress.

Ask whether your symptoms fit heat exhaustion or dehydration and whether medicines, heart rhythm, blood count, or blood sugar need review. Tell the clinician how long you were exposed to heat, your activity, drinks, sweating, urine, medicines, and the symptoms that continued after cooling.