LAUSR

This study aimed to analyze the longitudinal influence of sitting time (ST) on cardiac autonomic modulation (CAM) and resting heart rate (RHR) in a 12-month cohort of 67 breast cancer survivors. CAM was assessed by heart rate variability with heart monitor which also assessed RHR, and ST was self-reported. The relationship between the variables was analyzed by the Pearson correlation and its magnitude by linear regression. At baseline, no associations were found between ST and CAM or RHR. In the delta analyses, a decrease in RMSSD, SD1, and HF(ms2) was associated with sitting time. At 12-month follow-up, there was an increase in the ST and a decrease in RHR. ST was negatively related with CAM (RMSSD, PNN50, and SD1), but no association was observed between ST and RHR. The increase in ST was associated with worsening of CAM after 12-month follow-up. Promoting reduction in ST will be an important strategy against cardiovascular impairment in breast cancer survivors.