Physical activity and cognition: longitudinal findings from the Thinking and Living with Cancer Study.

BACKGROUND: Physical activity can improve cognition; however, little is known regarding the relationships between longitudinal objectively measured physical activity, cognition, and inflammation in older breast cancer survivors. METHODS: Older (aged 60 years and older) breast cancer survivors (n = 216) and frequency-matched noncancer control participants (n = 216) were assessed at baseline (presystemic therapy for survivors) and annually for up to 5 years. Assessments included hip-worn actigraphs worn for 7 days, neuropsychological tests, the Functional Assessment of Cancer Therapy-Cognitive Function perceived cognitive impairment subscale, and circulating levels of C-reactive protein and interleukin-6. Data were analyzed using linear mixed-effect, random-effect contemporaneous fluctuation, and multilevel mediation models, considering covariates; a P value less than .05 (2-sided) was considered statistically significant. RESULTS: Survivors had fewer minutes of moderate-to-vigorous physical activity than controls at 36-, 48-, and 60-month time points (P < .03). Fewer survivors met aerobic physical activity guidelines at 36 months than control participants (17.7% vs 33.0%, P = .030). When guidelines were met (vs not), Functional Assessment of Cancer Therapy-Cognitive Function perceived cognitive impairment scores were 2.1 (1.0) (P = .034) points higher. Higher moderate-to-vigorous physical activity and meeting aerobic guidelines were not related to objective neuropsychological performance. Moderate-to-vigorous physical activity was inversely associated with C-reactive protein and interleukin-6 (P < .001), but inflammation did not mediate physical activity effects on perceived cognition. CONCLUSIONS: Older breast cancer survivors were less physically active than older noncancer controls, especially farther from baseline. Meeting aerobic guidelines was associated with better perceived cognition in survivors. Survivorship care should consider physical activity monitoring and referral to rehabilitation and supervised exercise programs to promote physical activity and improve recovery in older survivors.