Prolonged immobility, particularly when seated, may lead to pooling of blood in the legs which in turn may cause swelling, stiffness and discomfort. Circulatory stasis is a predisposing factor for the development of venous thrombosis (blood clots). Most venous thrombi do not cause any symptoms and are reabsorbed without any consequences. Very rarely, however, small pieces of clot may detach and be carried through the blood stream to the heart and onward into the lungs causing a pulmonary embolus. This usually occurs only where there is already an extensive clot in the leg and may happen many hours or days after the formation of the clot. It may result in serious consequences including chest pain, shortness of breath and even sudden death.
The risk of developing deep vein thrombosis is very small for travelers unless they have pre-existing additional risk factors for thromboembolism, which include but are not limited to:
- Previous history of venous thrombosis or pulmonary embolism
- Aged 40+ years
- Use of hormone therapy
- Recent surgery or trauma
- Genetic blood clotting abnormalities
Some researchers also suggest that, in addition, there may be a risk from tobacco smoking, obesity and varicose veins. People in these risk groups should seek medical advice before traveling.
Advice for Patients with Risk Factors
Carrying out simple exercises at frequent intervals during the flight can reduce the negative effects of prolonged immobility. Most airlines provide helpful advice on in-flight exercises to stimulate circulation and reduce stiffness, discomfort and fatigue as well as lowering the risk of developing deep venous thrombosis (DVT).
In addition, passengers are advised to:
- Drink adequate fluids
- Avoid smoking
- Avoid alcohol
- Avoid crossing legs when seated
- Stretch arms and legs every 30 minutes
- Wear loose fitting comfortable clothes when traveling
- Avoid taking sleeping tablets.
After arrival at the destination, the effects of the journey can be reduced by gentle exercise to stimulate the circulation.