Fear and low blood sugar are only some of the reasons why otherwise healthy people faint. Fainting causes a temporary loss of consciousness and occurs when the blood flow to the brain is reduced or when there is excessive loss of blood or tissue fluids.

Low blood pressure is a common cause of fainting. Some healthy people naturally have low blood pressure which isn't harmful unless it falls below a critical level. A lack of sugar can sometimes be the cause, although this is more likely to occur in individuals who are insulin dependent diabetics. Having a fright, seeing something unpleasant or standing up for too long can also lead to fainting. Fainting in pregnancy is quite common and is usually perfectly normal. Sometimes fainting can be a symptom of anaemia. Drugs which act on the brain or which are used to treat angina can also cause fainting.

Fainting attacks come on gradually so if you can recognise the signs that you're going to faint - lightheadedness, sweating and blurred vision - you can usually stop yourself by sitting down, putting your head between your knees and taking several slow deep breaths. Then if you need to, you should lie down and raise your legs so that the blood flow to your brain can be maintained. You'll feel better once flow is restored but you should remain lying down for ten to fifteen minutes afterwards to make sure that you fully recover. Get plenty of fresh air and loosen any tight clothing.