Question: I’m in my 50s, a lifelong cyclist doing 175 -200 miles per week. As a result of earlier trauma to the lower leg and varicose veins, three years ago I had a deep vein thrombosis (DVT) that resulted in pulmonary embolisms (PE). Luckily the PEs were not big and I was soon back to riding while on Coumadin. Two weeks ago I got another DVT in the same leg, but caught it before it became a PE. I was doing a long, hard climbing ride on a hot day and was dehydrated, which might have contributed.
I’ve just started riding again, short miles, and I feel good although with some mild vein aches in that leg. I’m on Coumadin again and wearing compression. I’ve found very little info online about cycling and DVTs, and no scientific studies about it. Does cycling put me in danger? — Dave C.
Dr. Richard Ellin Responds: Deep vein thrombosis (DVT) is the medical term for a blood clot in one of the veins, most often one of the deep veins in the leg. These can occur spontaneously in people who are genetically at increased risk, and can occur as a result of other factors as well.
Some of these factors are: prolonged immobilization (such as a long car or plane trip, or prolonged bed rest), recent surgery, during and shortly after pregnancy, and due to certain medications (most commonly oral contraceptives). Certain cancers also can increase one’s risk of a DVT.
The symptoms of DVT can include swelling, redness, and warmth of the leg, and pain in the calf or thigh, although some people have no symptoms at all.
Typically, exercise involving the legs (cycling, walking, running) reduces the risk of deep vein thrombosis. I’m not aware of any data that show an increased risk with cycling.
When someone without apparent risk factors has a second venous thrombosis, as you did, Dave, we look for an underlying cause, such as a genetic predisposition.
In your case, presumably your doctors have already done so, but if not you should have a complete hypercoaguability workup (a battery of blood tests). You should also have a complete physical exam and complete screening for the common cancers that we can screen for (PSA for prostate cancer, colonoscopy, chest X-Ray).
Assuming nothing is found, in my opinion there’s no reason not to continue cycling. In my research, I have found no data that show a causative link or correlation between cycling and an increased risk of DVT.
You do raise a couple of other issues worth discussing here. First, cyclists need to pay attention to their hydration and stay hydrated. Too often, riders are underhydrated.
Also, cyclists need to stand and stretch while riding long distances. Doing so helps to avoid compression of the big veins in our legs.
Another thing to keep in mind is that all calf strains are not muscular in nature. DVT should be considered as a possible cause at some point. The literature is full of stories where cyclists went for medical help with calf pain and were treated as if they had a strain, only to wind up with a DVT. Early treatment of this problem can save a cyclist’s life and will allow a rider to return to cycling in a reasonable amount of time.
(Editor’s Note: RBR reader David Osler, who is a physician and suffered from a DVT resulting in a PE, contributed to this column.)
Richard Ellin, MD, FACP, is a board-certified specialist in Internal Medicine who practices in Alpharetta, Georgia. He received his medical degree and completed residency at Emory University, and has been in practice with Kaiser Permanente for 26 years. He is also an avid cyclist.