Aerobic physical activity and salivary cortisol levels among women with and without a history of breast cancer


Background: Researchers have provided evidence that physical activity (PA) improves health for women with and without a history of breast cancer (BC). More specifically, they have shown that PA helps reduce cancer-related symptoms (e.g., fatigue, depression, subjective stress, anxiety) and improves overall physical functioning in women with a history of BC. Yet, few researchers have examined the relationship between PA and physiological measures of stress. Thus, the aim of this study was to determine whether self-reported aerobic PA was associated with diurnal and reactive cortisol patterns, and whether these associations differed for women with and without a history of BC. Methods: Participants were 25 women with a history of BC (M time since diagnosis = 6.5 years) and 23 women without a history of BC who self-reported their PA level. To assess salivary diurnal cortisol patterns, participants provided five saliva samples collected on two consecutive days at the following times: upon awakening, 30 minutes after waking, 12PM, 4PM, and 9PM. To measure reactive cortisol patterns, participants provided seven saliva samples collected before, during, and after the Trier Social Stress Test. Data were analyzed using two-way analysis of variance (ANOVA) and mixed-design ANOVAs. Results: Cortisol patterns differed statistically based on women's history of cancer, whereby women without a history of BC had significantly higher overall cortisol reactivity to an acute stressor, but patterns did not differ statistically based on participants' aerobic PA level. Conclusions: Findings suggest that aerobic PA may not have the same effect on women with and without a BC experience.

Acknowledgments: The authors would like to thank all participants for their generous collaboration. We also would like to acknowledge funding for this study from the Canadian Breast Cancer Research Alliance.