Purpose/objectives: To identify indicators involving circadian activity/rest cycles associated with higher levels of cancer-related fatigue (CRF) during the first three chemotherapy cycles after surgery for stage I/II breast cancer.
Design: Prospective, descriptive, repeated measures.
Setting: Midwestern oncology clinics and subjects' homes.
Sample: 72 women, ages 33-69 and free of unstable chronic illnesses, entered the study. Complete data were obtained from 30-47 subjects at each time.
Methods: CRF was measured using the Piper Fatigue Scale at the start and midpoint of each chemotherapy cycle. Circadian activity/rest indicators were obtained using Mini-Motionlogger wrist actigraphs for 96 hours at the start of each treatment and for 72 hours at the midpoint of each chemotherapy cycle.
Main research variables: Fatigue and circadian activity/rest indicators.
Findings: Women who were less active and had increased night awakenings reported higher CRF levels at all three cycle midpoints, with the strongest association being number of night awakenings. During the third chemotherapy cycle, women who were less active during the day, took more naps, and spent more time resting during a 24-hour period experienced higher CRF.
Conclusions: Women whose sleep is disrupted at cycle midpoints are at risk for CRF. The cumulative effects of less daytime activity, more daytime sleep, and night awakenings are associated with higher CRF levels.
Implications for nursing practice: Assessment of CRF and night awakenings at the midpoints of each chemotherapy cycle and development of nursing interventions to promote daytime activity and nighttime rest are key to managing fatigue and preventing loss of biologic rhythmicity.