Dose-Response Effects of Acute Aerobic Exercise Duration on Cognitive Function in Patients With Breast Cancer: A Randomized Crossover Trial.

OBJECTIVE:To examine the differential effects of acute exercise duration on domains of executive function and processing speed in patients with breast cancer. METHODS:Participants (N = 48, M age = 56.02 ± 10.99) completed two sessions in counterbalanced order: moderate-intensity treadmill walking and sitting. Participants were also randomized to one of three duration conditions: 10 (n = 15), 20 (n = 16), or 30 (n = 17) min, reflecting the length of time spent walking and sitting. Immediately before and after each session, women completed a battery of cognitive tasks (e.g., inhibition, cognitive flexibility, spatial working memory, and processing speed). RESULTS:Within- and between-subjects repeated-measures analyses of variance revealed time by condition interactions on both processing speed (p = 0.02) and spatial working memory (ps < 0.07), such that women demonstrated improved cognitive functioning regardless of the time spent walking. There were also several moderately sized three-way (e.g., time by condition by duration) interactions driven by declines in cognitive functioning after sitting on cognitive flexibility in the 10 (d = -0.96) and 30-min (d = -0.52) groups and inhibition in the 20-min group (d = 0.75). On the processing speed task, women performed significantly faster after walking compared with after sitting in the 20-min group (d = -0.24). CONCLUSIONS:For select cognitive domains, walking anywhere from 10 to 30 min is associated with significant benefits. Our findings suggest the need for further research into the mechanisms and dose-response relationships between acute exercise and cognition as well as how such acute bouts may be accumulated for larger, lasting cognitive benefits after breast cancer. CLINICAL TRIAL REGISTRATION:www.ClinicalTrials.gov, identifier NCT04255225.