Dizziness: Does my lifestyle have anything to do with it?

Why is it that whenever I bend down and then stand up suddenly I feel dizzy?I have had a normal ECG and blood test. I am a 58-year-old man, a smoker, slim build and reasonably fit. I work in an office and walk for two to three hours a day.

Dr Fred Kavalier answers your health question:

You feel dizzy when you stand up quickly after bending down because your blood pressure is unable to pump enough blood to your brain. When your brain is short of blood and oxygen, it makes you feel dizzy. At the same time you may feel a pounding in your head, as your body tries to compensate by letting more blood get to your brain. The technical name for this problem is postural hypotension, which means that your blood pressure drops when you stand up. This can be a side effect of some blood pressure medications, but many healthy people notice this kind of dizziness as they get older. The problem may also be worse if you don't drink enough fluids during the day, or if your salt intake is too low. You should get your blood pressure checked. Smoking will not help the problem, as it makes blood vessels less responsive.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.