My wife and I are in our seventies, and sleep seven or eight hours a night, and often have an afternoon nap as well. Many other people our age have a lot of trouble sleeping, or sleep for far less time. Is there something wrong with us?
Sleep patterns are an extremely individual characteristic, and vary markedly from one person to another.
Generally, the amount of sleep required slowly decreases from infancy, through childhood to adult life and old age, but there are exceptions to every rule.
Some adults cope quite well on five hours sleep a night, while others (particularly teenagers) seem to require nine or even ten hours a night to function well. Others have frequent brief naps and cope well with life.
The ease of sleeping also varies—those who cannot easily get to sleep and wake frequently, are annoyed by those who can fall asleep in a minute and remain in that state, oblivious to their partner’s restlessness, for the entire night.
The amount of sleep that you need is the amount that suits you—and only you.
Inadequate sleep makes you tired (obviously), but also irritable and decision making can be affected. On the other hand, too much sleep can also be detrimental, causing headaches and light-headedness.
There is nothing wrong with you or your sleep pattern, and you are probably the envy of your peers.

I am always sleeping. I fall asleep at work, in the train (and miss my station), in front of TV etc. What could be wrong with me?
Doctors will immediately consider the diagnosis of narcolepsy, which is a rare form of epilepsy that causes people to suddenly fall asleep, sometimes in the middle of a sentence, or when half-way across a pedestrian crossing. This condition has obvious dangers, and requires urgent treatment.
It is far more likely that you are merely over tired from work, play and activities. Many medical conditions from anaemia and chronic infections to an underactive thyroid gland and the side effects of medications can cause you to be tired and fall asleep. Your quality of sleep may also be poor, leading to chronic tiredness. You will need to be examined and investigated by a doctor to get to the bottom of the problem.

What is involved in an MRI scan? I have seen numerous doctors about my headaches and fainting, and now a neurologist wants me to have one of these tests.
Magnetic resonance imaging (MRI), or nuclear magnetic resonance (NMR) as it is sometimes called, is a new technique of scanning the body. It is based on the fact that living tissues give off their own special electromagnetic signals, depending largely on their water content, and if the tissues are exposed to a magnetic field the signals can be picked up and read. Hence, a very strong magnetic field is created by special magnets, and different areas of the body absorb different amounts of magnetism according to their water content. A magnetic absorption photograph is then built up, and can be seen and analysed, slice by slice, on a computer screen in much the same way as a CT scan. MRI is particularly useful as it ignores bones (which contain little water) and shows up soft tissue, which is the opposite of X-rays.
MRI is especially helpful in diagnosing diseases in the brain and spinal cord. The picture obtained by MRI of the brain clearly shows the difference between the white matter (nerve fibres) and the grey matter (nerve cells). Tumours that are not apparent on a CT scan are sometimes revealed by MRI, not only in the brain but in organs deep within the abdomen such as the liver.
MRI is completely safe. Its main disadvantage is that the equipment is enormously expensive (approximately twice as expensive as a CT scanner) and must be housed in a special magnetically sealed room. As a result, high fees must be charged for its use, and not all of these are covered by Medicare or private health insurance.