Can flight socks prevent DVT?


Q. I am going to be flying to Bangkok and Melbourne soon - two flights of nearly 12 hours each. Should I be wearing compression stockings?

A. A deep-vein thrombosis (DVT) is a blood clot that forms in a vein, often in the leg. The reason why DVTs form is complex, but one factor is immobility. Movement and exercise tighten the calf muscles, and this squeezes the veins of the leg and acts as a pump to keep the blood flowing. When blood flow slows down, a clot is more likely to form. These clots can then dislodge and shoot off towards the lungs. A big blood clot that travels to the lungs can be fatal. This is known as a pulmonary embolism. Compression stockings put graduated pressure on the legs to keep the veins squeezed relatively closed. This makes it less likely that a clot will form. In a combined analysis of research studies that included more than 2,500 long-haul passengers, DVTs were nearly 25 times more likely in people who did not wear stockings, compared with those who did wear them. The research was not able to say whether stockings can prevent fatal pulmonary embolisms, because none of the people who developed DVTs went on to collapse and die from embolisms. For flights lasting more than seven hours, stockings probably are a good idea. It's also important to drink plenty of non-alcoholic fluids (to prevent dehydration) and to take exercise by walking up and down the aisles and regularly wiggling your feet and ankles.


Q. I suffer a horrendous level of tinnitus noise to both sides of my head. The only treatment for tinnitus at the moment is so-called "noise management" using "white noise" generators. These help, but the relief is temporary. Why has the NHS and medical research deserted people like myself?

A. The NHS and medical research hasn't deserted tinnitus sufferers. But there is no single treatment that is best for everyone. Tinnitus is a noise in the ears or head that is generated by the part of the nervous system known as the auditory pathway. This pathway starts in the ear, and ends up in the brain. Tinnitus is different from auditory hallucinations, and sometimes occurs because of disease in the ears, but it can also occur without any ear problems. The symptoms are always worse when there is no other noise present, so you should try to avoid very quiet environments. Other noises mask the sounds of tinnitus, and make it easier to disregard the condition. You should make contact with the British Tinnitus Association, which is an active UK charity dedicated to helping people with tinnitus (; 08000 180 527).

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or e-mail Dr Kavalier regrets that he is unable to respond personally to questions.

Readers write

CR takes pills before hitting the beach:

I have a bad reaction to sunlight - my doctor calls it an allergic reaction which produces prickly heat. If I get the rash it lasts for a fortnight. I control it using a non-drowsy anti-histamine on hot sunny days (I use Zirtek but there are others). Take it 20 minutes before exposing yourself to sun and you should be fine.