Heat nausea

Hot conditions increase the body’s effort to release heat. Sweating can reduce fluid and salt levels, while blood flow shifts toward the skin. Together, these changes may cause nausea, thirst, headache, weakness, dizziness, or vomiting. Nausea after a meal, with diarrhoea, upper abdominal pain, yellowing of the skin, burning behind the breastbone, or shaking may have another explanation, such as gastroenteritis, food poisoning, gastritis, acid reflux, gallstones, hepatitis A, or low blood sugar.

Stop activity and move to a cool, quiet place. Sit or lie down, loosen tight clothing, and take small sips of water or an oral rehydration drink if you are awake and able to swallow. Avoid alcohol and heavy meals until the stomach settles. If vomiting continues, note how often it happens and whether you are passing urine. People with fluid or salt restrictions should follow their clinician’s advice rather than forcing drinks.

Get urgent help for confusion, fainting, seizure, severe weakness, chest pain, severe abdominal pain, blood in vomit or stool, yellow skin, or trouble breathing. Seek help promptly if you cannot keep fluids down, pass very little urine, or become increasingly drowsy after heat exposure. Ongoing or recurrent nausea needs assessment even when the weather is mild.

Ask whether heat illness fits the timing, which symptoms suggest a stomach or abdominal cause, whether medicines affect nausea, and how to replace fluids safely.