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Heat exhaustion and heatstroke are two potentially serious conditions that can occur if you get too hot.
Carbon monoxide is a poisonous gas that has no smell or taste.
Hypoglycaemia, or a "hypo", is an abnormally low level of glucose in your blood (less than four millimoles per litre).
Our Health A-Z contains more information on the above symptoms.
Important: If you have these symptoms, they may be unrelated to any of these conditions listed. If you are concerned about your symptoms then you should see a doctor.