Exercise Fights Fatigue, Loss of Physical Function in Breast Cancer Patients

BALTIMORE—New research indicates that exercise can play a significant role in combating fatigue related to cancer treatment and the accompanying loss of function fatigue brings, according to Victoria Mock, DNSc, RN. Dr. Mock is the American Cancer Society Professor of Oncology Nursing at Johns Hopkins School of Nursing and Director of Nursing Research Center at the Sidney Kimmel Comprehensive Center at Johns Hopkins in Baltimore.

Fatigue is a major side effect of cancer treatment, contributing significantly to decreases in activity that lower quality of life during treatment and lead to long-term loss of function. Fatigue has, however, received little research attention, Dr. Mock said, and practitioners have traditionally just advised that patients rest when they complain of fatigue.

Exercisers Gained Function

In a study of 120 breast cancer patients, those who exercised regularly suffered much less fatigue than those who didn’t and even gained rather than lost functional ability, she reported. The descriptive, correlational study was a substudy of a randomized clinical trial involving five academic cancer centers and 35 nurses.

The patients, who were all receiving either radiation treatment or adjuvant therapy, were divided into exercise and nonexercise groups. Those in the exercise group received written prescriptions to walk for up to 30 minutes a day, 5 or 6 times a week. Women who already exercised regularly and actively were not eligible for the study.

Each subject was evaluated at the beginning and end of the exercise study for fatigue using the Piper Fatigue Scale, for self-assessed physical functioning with the Medical Outcome Study Short Form 36 (MOS-SF 36) Physical Functioning Subscale. Objective assessment of physical function used the 12-Minute Walk Test.

‘‘At posttest, participants who were in the highest quintile of fatigue scores had the lowest physical functioning scores and participants in the quintile of lowest fatigues scores scored highest on physical functioning even though physical functioning scores of two quintiles has been similar at pretest.’’ The posttest also revealed a marked inverse correlation between exercise and fatigue; exercisers had mild fatigue and nonexercisers moderate fatigue. Seventy-two percent of the exercise group had followed their prescriptions, averaging 29 minutes daily 4 days a week. They also showed "significantly higher" physical functioning, having gained 200 feet on the 12-Minute Walk Test, as compared to a 67-foot loss for the nonexercisers, Dr. Mock noted.

Physical function correlated inversely with mood disturbance and symptom distress. The women in the highest quintile of physical function experienced low levels of mood disturbance and symptom distress as they gained in walking ability. Mood disturbance and symptom distress levels rose as the physical function level dropped.

Which Comes First?

The study did not answer the "chicken and egg" question of whether patients lose capacity because they are fatigued or are fatigued because they have lost capacity, Dr. Mock acknowledged. But it did demonstrate that "moderate, regular walking" can help women maintain physical functioning and fight fatigue while they undergo cancer therapies, she said, adding that patients clearly need both rest and exercise. The results also indicated that physical functioning has not received enough attention from oncology nurses.

"More that 50% of our patients will be cured," she said, and oncology nurses need to help them protect their physical functioning for their lives after treatment.