RESUMO
BACKGROUND: Exercise seems to protect from breast cancer (BC) and this protection is likely mediated through weight control during menopause. Considering that night work is associated with higher risk for BC. OBJECTIVE: The aim of this study was to examine the possible relation of BC risk to daytime or nighttime hours of exercise. METHODS: The material was taken from primary elements of a doctoral thesis at the Department of Midwifery, University of West Attica that examines the impact of the characteristics of exercising on BC. The data were obtained from relevant questionnaires filled in at a big private hospital, following a relevant permit of the scientific committee, and adjusted Google Forms, ensuring anonymity. RESULTS: Almost 3 times more women without a history of BC were exclusively exercising during the daytime compared to the ones with a history of BC who were exclusively exercising during the nighttime (40 vs 15). On the contrary, a smaller number of women without a history of BC were exclusively exercising during the nighttime compared to the ones with a history of BC who were exclusively exercising during the nighttime (17 vs 20) (odds ratio >3 with a confidence interval >1 to >7.5 and p<0.05). CONCLUSION: It seems that the protective impact of exercising on BC is mitigated when the exercise is performed exclusively during night hours.
