Feeling sick from heat

Heat makes the body send more blood to the skin and lose fluid through sweating. If fluid and salts are not replaced, you may develop nausea, thirst, headache, dizziness, weakness, muscle cramps, or heavy sweating. Hot environments can also worsen an unrelated illness, including a stomach infection or food poisoning. Reflux or gastritis may feel worse after eating in discomfort, but heat-related symptoms usually improve after cooling and drinking.

Risk rises during exercise, outdoor work, travel, or time in a poorly ventilated room. Young children, older adults, pregnant people, and anyone with a chronic illness may need help cooling down and drinking safely.

Stop exertion and rest in shade or an air-conditioned room. Loosen extra clothing, cool the skin with wet cloths or a fan, and take frequent small sips of cool water or an oral rehydration drink. Avoid alcohol and strenuous activity while recovering. If vomiting prevents fluids staying down, seek medical advice rather than forcing large drinks.

Call emergency services if the person is confused, has a seizure, collapses, cannot drink, has very hot skin, or does not improve quickly with cooling. These can signal heatstroke. Get same-day care for worsening dizziness, faintness, repeated vomiting, severe headache, marked weakness, or very little urine. Do not leave an unwell person alone in the heat.

Ask whether your symptoms fit heat exhaustion, how much fluid is suitable with your health conditions, and when it is safe to return to work, exercise, or outdoor activity.