WORCESTER, Mass. (AP) — Dr. Robert A. Phillips, senior vice president at the University of Massachusetts Medical School and director of the UMass Memorial Medical Center’s Heart and Vascular Center of Excellence, walks about two miles a day as he makes telephone calls, answers email correspondence or meets with colleagues in his University Campus office.
Instead of outfitting his office with a traditional desk and chair, Dr. Phillips works at a walk-station desk affixed above a treadmill, allowing him to conduct regular business while keeping active.
It’s a healthful practice, according to medical researchers who say that sitting for prolonged hours, as many office workers do, can lead to dangerous blood clots.
‘‘I have otherwise a very sedentary job,’’ Phillips said. ‘‘It’s difficult for me to work in exercise, although I tried hard to do it.’’
He said that keeping on the move during the workday, even at 1 to 2 mph, helps him maintain a healthy weight.
Dr. Louis Messina, chief of vascular surgery at UMass Memorial Medical Center, said there’s a lot of evidence linking prolonged inactivity to blood clots, including deep-vein thrombosis in the legs or the general disease process known as venous thromboembolism.
The immediate risk of VTE/DVT is that a clot can break off and go to the lungs, a pulmonary embolism, which can be fatal. Pulmonary embolisms occur in 10 percent of patients with DVT.
‘‘It’s not rare,’’ Messina said. ‘‘Unfortunately, it’s a cause of sudden death.’’
Other complications include post-thrombotic syndrome, a debilitating intermittent swelling of the leg, and ulceration from persistent swelling, or edema.
VTE and DVT were first studied among people sitting upright in cramped air-raid shelters during World War II and then among people who sat on long airline flights.
‘‘It’s thought to be due to the stasis, sitting in cramped spaces for a long time,’’ Messina said, which causes the blood to pool. Dehydration can also increase the risk of clotting, as well as factors such as age (40 or older), obesity, pregnancy, recent surgery or a genetic predisposition.
More recently, Messina said, simply staying seated for prolonged periods of time — whether in a cramped airplane seat or at a workstation in front of a computer — has been identified as a risk factor.
He said the risk of VTE increased by 10 percent per hour among people seated for eight hours or more. The length of time sitting matters as well as the total amount of time spent sitting in a typical day.
‘‘Common sense recommendations are to get up and walk around every 30 to 60 minutes,’’ Messina said. Two hours seated at a time should be about the maximum.
‘‘Stay hydrated, which makes it less likely for blood to clot,’’ he added.
If you’re in an airplane for several hours or can’t leave your desk to walk around, Messina suggested moving your feet and doing some calf compressions or leg exercises from your seat.
People who have DVT/VTE should take blood thinners such as warfarin (sold under the trade name Coumadin) for at least several months, and those with a genetic predisposition may need to wear graduated compression stockings that help pump blood out of the legs. Others may need to inject blood thinners.
While not everyone can install a walk station in their office, taking a walking break helps with weight loss and cardiovascular health.
‘‘I like work better,’’ Phillips said. ‘‘I don’t have the guilt of not exercising.
‘‘I'm clearly able to climb steps better, and my wife noticed more pep in my step.’’