Relationships of exercise timing with sleep, fatigue and rest–activity rhythms of lung cancer patients in Taiwan: An exploratory study

Objective: To explore the relationship of exercise timing (exercising close to bedtime, exercising in daylight and maintaining fixed exercise schedule) with sleep quality, fatigue and rest-activity rhythms among lung cancer patients in Taiwan.Methods: Results from 43 lung cancer patients who were assigned and adhered to the exercise intervention in a 12-week randomised controlled trial were analysed. The MD Anderson Symptom Inventory and Pittsburgh Sleep Quality Index (PSQI) were administered. Actigraphs were used to assess rest-activity rhythms (in-bed less than out-of-bed dichotomy index, I < O) and objective sleep parameters, including total sleep time (TST) and sleep onset latency (SOL).Results: Patients who exercised >4 hr before bedtime had significant improvement in fatigue (p < .0001), sleep quality (p = .012 for PSQI; p = .037 for TST; p = .017 for SOL) and rest-activity rhythms (p = .048 for I < O). Furthermore, patients who exercised with daylight exposure had a significant improvement in fatigue (p = .037) and sleep quality (p = .039 for PSQI).Conclusions: Exercising >4 hr before bedtime with daylight exposure is associated with improvement in rest-activity rhythms, sleep quality and fatigue in lung cancer patients. The causal relationship requires further investigation with experimental design.