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Prolonged sitting for hours, for example, on long flights and at work desks can put one at risk of developing clots in their limbs and can affect their heart, warn experts. They can develop dehydration, adding to the risk of deep vein thrombosis or DVT, where clots are formed in the veins, which carry blood back from the lower limbs to the heart and lungs.
Deep vein thrombosis
Dr. Krishna Chaitanya, lead consultant, department of vascular and endovascular surgery at Aster CMI Hospital, Bangalore, says the veins in the legs carry a majority of the blood upwards against gravity. “So, the blood travels very slowly up towards the heart as and when we move and our muscles contract. Now, there are certain conditions which can cause clots in these veins. This is called deep vein thrombosis,” he adds.
DVT can be dangerous if a large clot is blocking a vein. Dr. Jyoti Kusnur, the interventional cardiologist at Manipal Hospital, Goa, says, “If the clot is localized, like in the calf muscle, it can get swollen up, turn red and be a little painful. But if the clot extends from the calf to the knees, thighs, heart and then lungs, causing pulmonary embolism, it can get dangerous. That can be a medical emergency.”
Can DVT cause a heart attack?
Arteries carry blood away from the heart and veins carry blood towards the heart. Hence, heart attacks are usually caused by arterial thrombosis where blood clots are formed in the arteries.
In deep vein thrombosis, veins are involved and hence, it cannot cause myocardial infarctions or heart attacks. Dr Chaitanya says, “In DVT, when the clots go into the lungs, the pressure in the right side of the heart rapidly rises and it cannot pump well, causing heart failure. Hence, DVT can be one of the causes of cardiac arrest but not heart attacks.”
Risk factors that can cause DVT
Experts say some of the factors that can cause deep vein thrombosis include:
- Smoking cigarettes
- Obesity
- Dehydration
- Genetic issues
- Heart failure
- Sedentary lifestyle
- Prolonged sitting like on long flights
- Being bedridden due to medical conditions
- High sugar, blood pressure and cholesterol
Dr Chaitanya explains, “Sometimes, women take contraceptive medications or some pills to postpone their menses. These medications can thicken the blood and cause deep vein thrombosis. Direct injury to the veins in a road accident can cause the veins to lose their quality, making the blood in them rot. Plastering leg due to fracture can also make the muscles immobile, affecting the blood flow and leading to clots.”
Why flying causes blood clots?
Sitting in one position on long flight journeys without enough legroom, pose a serious risk factor for DVT. Experts say the negative air pressure in the cabin can impair the blood flow and cause dehydration, thickening the blood. Dr Kusnur says, “For every hour of flying, one loses almost 500 ml of water from their body. Hence, the Directorate General of Civil Aviation (DGCA) has mandated aircrafts to provide free drinking water.”
Dr Chaitanya adds that people also tend to consume alcohol on long flights, which again is dehydrating.
Deep vein thrombosis symptoms
Unilateral limb swelling or swelling in any limb (unless and until proven to be any other condition) is suspected to be DVT. One can also develop pain and difficulty in walking. If one experiences any chest pain or breathing difficulty or cough, they should seek emergency medical care, say experts.
Complications of deep vein thrombosis?
The immediate complication is that the blood supply to the limb gets cut off and your leg starts to swell, says Dr Chaitanya. “There can be a venous gangrene of the limb. When the clot goes into the heart and then the lungs, one might develop sudden breathlessness because the lungs are clogged with clots. There will not be any exchange of oxygen or carbon dioxide. The BP suddenly drops, and it can be life-threatening,” he adds.
The long-term complications include damage to the structure where there are clots, be it in the lungs or legs. It can lead to pulmonary arterial hypertension or hypertension in the lungs. One can develop breathlessness walking just 50 to 100 meters. Dr Chaitanya adds that there can be chronic blockages in the legs, leading to venous hypertension in the legs. “Swelling in the legs can cause complications to a point where there will be cracks and oozing of fluids. It forms wounds in the legs which fail to heal and the quality of life is severely impaired,” he says.
Treatment and prevention
Dr Kusnur says DVT is a completely curable condition if picked up early. “The treating doctor can immediately start the anti-clotting medication which will dissolve the clot and prevent any further damage. If it is picked up late, there can be permanent damage to the veins of the legs,” she says.
Following are the measures that can help prevent deep vein thrombosis.
- Stretching your legs
- Adequate hydration
- If in flight, take a short walk in the aisle when possible
- Maintain healthy lifestyle
- Prevent obesity
- Avoid smoking and alcohol
- Regular exercise
- Keep diabetes, blood pressure and cholesterol under check
Takeaways
- Deep vein thrombosis is the formation of clots in the veins that carry blood back from the lower limbs to the heart and lungs.
- If the clot travels to the right side of the heart, it can lead to heart failure.
- Symptoms of DVT include redness, swelling, pain, tightness of the leg muscles, chest pain and breathlessness.
- A sedentary lifestyle, chronic conditions like diabetes, a history of heart failure and sitting for prolonged periods add to the risk of deep vein thrombosis.
- Staying physically active, walking and staying hydrated during long flights and keeping blood pressure and diabetes under control can help prevent the condition.
