When people talk about things to avoid before diving, sitting still for too long doesn’t usually make the list. However, when divers fly to dream destinations that are several hours away, deep vein thrombosis (DVT) can be a real concern. DVT occurs when a blood clot forms in one or more of the body’s deep veins, usually in the legs, and can result in a pulmonary embolism or even a stroke. With a little knowledge, this condition is easily identifiable and more importantly, preventable.
Risk factors for DVT include prolonged bed rest or immobility, injury or surgery, pregnancy, use of oral contraceptives or hormone replacement therapy, obesity, smoking, cancer, inflammatory bowel disease, age (being over 60), height (being shorter than 160 centimetres/5 foot 3 inches or taller than 190 centimetres/6 foot 3 inches), personal or family history of DVT and sitting for long periods of time, such as when flying.
Most cases of DVT related to air travel occur within two weeks of a flight and are resolved within eight weeks. In about half of all cases, individuals experience no noticeable symptoms before the blood clot forms, and many asymptomatic cases resolve spontaneously.
If apparent, symptoms typically begin in the calf and, if left untreated, spread to the thigh and pelvis in about 25 percent of cases. An untreated DVT of the thigh and pelvis has about a 50 percent chance of leading to a pulmonary embolism, the most serious complication of DVT. If you or someone you know is at risk for developing DVT and experience any of the following symptoms, seek medical attention immediately.
- Swelling in the leg, ankle or foot
- Pain in the calf that spreads to the ankle or foot
- Warmth in the affected area
- A change in the color of the skin to pale, red or blue
To reduce your risk, avoid sitting still for prolonged periods: get up and walk around on the plane, and if you can’t, flex or massage your feet or calf muscles regularly. Wearing compression socks can also help to improve blood flow and prevent clotting. To further reduce your chance of experiencing DVT, exercise regularly and stay hydrated. If you’re at high risk for the condition or exhibit multiple risk factors, consult your physician regarding the potential benefit of taking a medication such as aspirin that may limit clotting. Divers who have been diagnosed with acute DVT or take anticoagulants should refrain from diving until cleared by a physician.