(NEW YORK) -- One of the most common problems that can plague those who have undergone mastectomies -- such as actress Angelina Jolie -- is lymphedema, a painful swelling of the arm.
Between 5 percent and 20 percent of women develop this chronic and debilitating condition in the first three years after surgery, according to the American College of Surgeons.
Not so long ago, patients with lymphedema were told to lay low. Doctors worried that even something as simple as holding a purse or pushing open a door would overuse the afflicted arm and worsen the swelling.
But the thousands of post-mastectomy patients who've take up the ancient Chinese sport of dragon boat racing -- paddling a large, long canoe with a dragon head at the front and a dragon tail at the back -- have helped change that thinking. Many swear by the sport as a way to help manage their hand and arm swelling.
"When I heard about dragon boat racing, I thought, Oh sure, that's for me," said Kathy Christiansen, a 58-year-old nurse who took up dragon boating in 2006 a few years after undergoing a partial mastectomy in her right breast. "I was told about all these restrictions, but I have always been an athletic person, and I couldn't see following them."
Christiansen said she rarely had lymphedema symptoms and believed it was because of all her physical activity since having surgery, not least of all dragon boat racing. At her last checkup, the doctor noticed her right arm was actually smaller than her unaffected left arm.
Dragon boating was first used for breast cancer recovery in 1996 by a physician trying to test his theory that more, not less, upper-body exercise could help reduce lymphedema. His subsequent studies found that paddlers had less swelling and fewer physical limitations compared with breast cancer survivors who did not exercise.
Since that first boat took to the water, more than a hundred breast-cancer survivor dragon boat teams have formed worldwide. The boats hold up to 20 paddlers plus a caller who sits near the head and someone in the back to steer the boat. In competitions, the caller also beats a ceremonial drum to help paddlers keep to the same rhythm.
Christiansen's team, Pink Paddling Power, was started as a support group by Wheaton Franciscan Cancer Care of the All Saints Hospital in Racine, Wis., and is supported by various grants and donations. There are currently more than 40 women on its active roster.
In 2006, 29 team members, ages 46 to 71, competed in the Club Crew World Championships of Dragon Boat Racing in Hong Kong, in the breast cancer survivors division.
But even with all the potential benefits dragon boating might offer a woman with lymphedema, Katherine Schmitz, an associate professor of epidemiology who studies breast cancer at the Perelman School of Medicine at University of Pennsylvania, advises caution.
"With any type of exercise, all breast cancer survivors need to start slow, progress low and let the symptoms be their guide," Schmitz said. "I'm just not sure how you do this with dragon boat racing."
While Schmitz is fan of dragon boat racing -- and any activity that gets breast cancer patients up and moving -- she said a supervised weight-training program in which the weight is increased gradually over time might be a more judicious approach for many.
In a one-year study of more than 150 women led by Schmitz, weight lifters slashed their risk of developing arm swelling by 35 percent. Only 11 percent of the group developed lymphedema, compared with 17 percent of those in the nonexercising group.
The women who'd had the most lymph nodes removed -- five or more -- experienced a nearly 70 percent risk reduction, with 22 percent of inactive participants developing lymphedema, compared with 7 percent in the exercising group.
Copyright 2013 ABC News Radio