br The importance of studying whether
The importance of studying whether PA can have a normalizing eﬀect on the Z-Guggulsterone secretion patterns among women once treatment for BC has ended is highlighted by findings showing that these women typically exhibit a flatter cortisol pattern in response to an acute stressor compared to women with no history of cancer.26–28 An ab-normal cortisol concentration pattern in response to acute stress si-tuations can lead to various negative health consequences because cortisol is essential for regulating bodily functions and responding to environmental challenges.23 Indeed, persistent low cortisol levels have been linked to pain, fatigue, high-stress sensitivity,29 and increased
Corresponding author at: School of Psychology, 2080 Vanier Hall, University of Ottawa, 136 Jean-Jacques Lussier, K1N 6N5 Ottawa, Ontario, Canada. E-mail address: [email protected] (M. Lambert).
M. Lambert et al.
vulnerability to stress-related bodily disorders.30,31 Moreover, mor-tality, disease severity, and several other negative health outcomes such as obesity,32 depression,33 and diabetes34 have been associated with general dysregulation of the HPA axis (i.e., atypical cortisol con-centration patterns).35,36
As several studies have reported that abnormalities in the cortisol secretion patterns of women treated for BC26–28,35,37–39 and given evi-dence of the benefits of PA on the overall health-related outcomes for women diagnosed with BC,1,3 it is important to investigate whether PA plays a protective role in the cortisol dysregulation found in women with a history of BC. In doing so, it is valuable to compare whether the role is comparable to that of women without a history of BC. Previous studies with adults without a history of cancer and with athletes both indicate that PA influences the functioning of the HPA axis and reg-ulates cortisol secretion,40,41 whereby PA generates an almost im-mediate HPA response by activating and stimulating cortisol releases. The long-term eﬀect of PA on cortisol patterns, however, remains un-investigated in these populations (as well as in women with a history of BC). The purpose of the present study was to extend this research and evaluate the association between aerobic PA and cortisol patterns among women with a history of BC who were, on average, 6.5 years post-adjuvant treatment as well as with women without a history of BC. The specific objectives were twofold: (1) assess whether aerobic PA was associated with diurnal and reactive cortisol patterns, and (2) de-termine whether the association between aerobic PA and cortisol pat-terns diﬀered between women with and without a history of BC. It was hypothesized that women with a history of BC who reported engaging in aerobic PA more frequently at the time of testing (moderate/high-PA group) would exhibit significantly less abnormalities in their cortisol patterns than those who reported engaging in aerobic PA less frequently or not at all (no/low-PA group). Given the exploratory nature of the second aim, no hypothesis regarding whether a cancer experience moderated the association between aerobic PA and cortisol patterns was proposed.
Women with and without a history of BC were recruited through printed advertisements and cancer support groups. To be eligible for this study, women with a history of BC had to meet the following cri-teria: (a) have been diagnosed with stage 0-III BC, (b) be more than 6 months post-adjuvant treatment (i.e., surgery, chemotherapy, and/or radiation therapy) for BC, and (c) be able to read and speak English. Women without a history of BC had to meet the following criteria: (a) have completed a routine mammography screening with negative re-sults, (b) have no history of other types of cancer (except non-invasive skin cancer and cervical cancer), and (c) be able to read and speak English. Women were not eligible if they: (a) had a substance abuse problem, (b) were suﬀering from a major disabling conditions inter-fering with their quality of life and level of functioning (e.g., psychiatric disorders), and/or (c) were breastfeeding, pregnant, or taking any medication that could alter hormonal secretion (e.g., hydrocortisone, hypnotics, benzodiazepines).
The study protocol was approved by the University of Ottawa's Research Ethics Review Board. All participants provided written in-formed consent prior to data collection, received financial compensa-tion for travel ($50 CAD), and were entered in a raﬄe to win one of four $250 CAD gift certificates. Once eligibility was confirmed over the phone, women were scheduled to attend two laboratory visits at the University of Ottawa Stress, Immunocompetence, and Health Laboratory. The first visit lasted approximately 30 min and served to