Some Breast Cancer Survivors Face Post-Treatment Fatigue

Women who have completed therapy for breast cancer often suffer from fatigue - a result of stress caused by a continuous shifting between "fight-or-flight" and "resting" patterns during treatment.

Researchers at Ohio State University believe that the rise in norepinephrine - a stress hormone responsible for short-term energy - followed by abrupt switches to energy conservation mode, is responsible for an imbalance among the two opposite functions of the body's autonomic nervous system. This imbalance, scientists believe, may be the cause of fatigue in cancer survivors - an important discovery, as prior findings indicated system-wide inflammation as the source.

"We're not sure if the fatigue is stress-induced. But certainly cancer is an extremely stressful life event," says study author Christopher Fagundes, Ph.D., at Ohio State University. "So those stressors might be contributing to those autonomic system changes."

What's to blame?

The findings are the most recent from a 30-year-long study about the effects of stress on the human body. The researchers used earlier data from a larger ongoing study looking at whether yoga can ward off continuing fatigue in breast cancer patients.

Study authors point out that more research is needed. "We cannot say with certainty that lower [heart rate variability found in the fatigued study participants] or higher norepinephrine leads to great fatigue, or vice versa, a limitation of the study," they wrote in the report. "It is possible that fatigued cancer survivors have [these levels] due to inactivity and deconditioning."

According to Fagundes, chronic fatigue in some breast cancer patients may be a sign of premature aging - their bodies responding as if they were 20 years older than patients who didn't suffer fatigue. Similar problems have been detected in other studies when comparing cardiovascular fitness among breast cancer survivors. Researchers believe certain drugs used to treat breast cancer are toxic to the heart and may be to blame for the exhaustion.

Fighting fatigue

Regardless of the cause, researchers say one way to ease cancer-related fatigue is to maintain an exercise program during and after treatment.

"Exercise is probably the best way to restore that balance," says Fagundes. "Obviously the goal is always to attenuate those negative effects."

Talk with your health care provider for more information.