Dr Clare Bailey interviews Prof Beverley Hunt to raise awareness of risk factors for blood clots and how to help reduce risks #NTW19

Soon it’ll be summer and many of us will be driving or flying long distances to go on holiday. The problem is that while travelling you’re sitting still and at risk of developing a blood clot in the leg, known as deep vein thrombosis (DVT).

David, 61, a cycling enthusiast, fit, active and healthy apart from occasional asthma, came back from a holiday involving a series of long-distance journeys. Having worn stockings on the plane and kept well hydrated, he assumed that when he started getting short of breath over the following weeks it was just his asthma. Several weeks later, he woke to find a painful and slightly swollen calf but put it down to an old achilles tendon injury. By then it had been a month since travelling, so he told the doctor he hadn’t been on a long-haul flight recently.

DVT can be dangerous – the clot can break off and travel around the body, eventually blocking the blood from circulating to your lungs, known as a pulmonary embolism.

Even 90 minutes of sitting can reduce blood flow by half

Within days David was urgently admitted to hospital with severe chest pains and difficulty breathing. He was diagnosed with DVT and blood clots in his lungs. Thankfully, he was given anticoagulants straight away and has remained well since, but David’s story is not unusual. Even 90 minutes of sitting is enough to reduce blood flow behind your knees by as much as half. So it’s no surprise that prolonged sitting puts you at risk of developing DVT, when blood flow is slow enough to form a clot. This can cause pain and swelling at the back of the leg over the following days or weeks, although there may be no symptoms.

According to Professor Beverley Hunt, medical director of Thrombosis UK, ‘Although there has been a lot of media attention around DVT when flying, the risk to anyone in good health is probably less than one in every 10,000 long-haul journeys. So you don’t need to be too worried.’ However, she advises that ‘there is an increased risk in people with “sticky blood”, known as thrombophilia’. This can be caused by being ill, inherited problems or taking the combined oral contraceptive pill. You are also at greater risk if you are obese, on hormone replacement therapy, pregnant or if you have recently had a baby.

Thrombosis UK offers this advice for long-haul flights:

  • Exercise your calf muscles regularly by contracting them and moving.
  • Don’t drink too much alcohol as it dehydrates you.
  • If wearing special medical stockings, make sure they are a good fit, otherwise they can cause more harm.
  • Avoid sleeping tablets as they can result in you sleeping in an awkward position and moving less.
  • Drink plenty of water.

Professor Hunt adds, ‘In the unlikely event that you do develop symptoms such as pain and swelling in your legs, unexpected shortness of breath or chest pain, you should seek medical treatment immediately.’

For more information, visit: thrombosisuk.org/what-is-dvt.php.