BAKERSFIELD, Calif. -- For the more than 2.4 million breast cancer survivors in the United States, swelling and discomfort of the limbs after surgery that removes lymph nodes or radiation to the nodes can be a chronic and incurable problem.

The swelling, known as lymphedema, affects as many as a quarter of breast cancer survivors. For years it was thought that overexertion would aggravate this condition, and doctors cautioned patients against using the affected limb for things such as picking up children or carrying grocery bags.

However, new research from the University of Pennsylvania has shown that moderate weight-lifting may actually lessen the severity of this condition.

After following patients for a year, the study found that weight-lifting twice a week increased the strength and mobility of the affected limbs and decreased limb discomfort.

Researchers hoped that in the future, weight-lifting interventions like these will help patients manage their lymphedema, allowing them to return to normal activity.