Relationship between exercise behavior, cardiorespiratory fitness, and cognitive function in early breast cancer patients treated with doxorubicin-containing chemotherapy: a pilot study

The purpose of this study was to examine the relationship between self-reported exercise behavior, cardiorespiratory fitness (CRF), and cognitive function in early breast cancer patients. Thirty-seven breast cancer patients following completion of chemotherapy (median 16 months) and 14 controls were studied. Cognitive function was assessed using the Central Nervous System (CNS) Vital Signs software (CNS Vital Signs, LLC, Morrisville, N.C., USA), a computerized test battery consisting of 9 cognitive subtests. Exercise behavior was evaluated using the Godin Leisure Time Exercise Questionnaire, and CRF was assessed via a cardiopulmonary exercise test to assess peak oxygen consumption. Patients’ mean total exercise was 184 ± 141 min·week−1 compared with 442 ± 315 min·week−1 in controls (p < 0.001). Significantly fewer patients (32%) were meeting exercise guidelines (i.e., ≥150 min of moderate-intensity or vigorous exercise per week) compared with 57% of controls (p = 0.014). Patients’ peak oxygen consumption averaged 23.5 ± 6.3 mL·kg–1·min−1 compared with 30.6 ± 7.0 mL·kg–1·min−1 in controls (p < 0.01). Scores on the cognitive subdomains were generally lower in patients compared with controls, although only the difference in verbal memory was significant (unadjusted p = 0.041). In patients, weak to moderate correlations were indicated between exercise, peak oxygen consumption, and the majority of cognitive subdomain scores; however, there was a significant positive correlation between exercise and visual memory (r = 0.47, p = 0.004). In conclusion, breast cancer patients following the completion of primary adjuvant chemotherapy exhibit, in general, worse cognitive performance than healthy women from the general population, and such performance may be related to their level of exercise behavior.