Previous research has established a relationship between physical activity (PA), sleep efficiency (S%) and heart rate variability (HRV). Our previous studies (Wolfe and Dennis, 2016) have further established this relationship, with significant findings when separating PA by intensity (Dennis and Wolfe, 2016).
PURPOSE: The purpose of the current study was to further investigate the relationship between PA and HRV. Specifically the primary aim of the study was to investigate the difference between BMI, PA and HRV.
METHODS: Nineteen subjects (20+1 yr.) from a Division I University volunteered for the study. All subjects voluntarily signed an informed consent and completed anthropometric measures including height, weight and BMI. Subjects were then fitted with a BodyMedia SenseWear Armband to assess PA and sleep efficiency for the duration of one week (7days). Upon returning the device, each subject had HRV assessed (CardioSoft software), utilizing a 12-lead EKG by assessing standard deviation of the mean R-R intervals (SDANN). Subjects were classified as “Normal” or “Overweight” according to their BMI and t-tests were utilized to compare the two groups.
RESULTS: Our results show that the “Overweight” category (mean BMI = 26.6 kg/m2) had fewer steps (79, 060) when compared to the “Normal” BMI category (mean BMI = 21.6 kg/m2 , steps 81,212). Our results also show that the “Overweight” category had a lower HRV score when compared to the “Normal” category. However, the results of the t-tests showed no statistical difference (p < .05) between the two groups.
CONCLUSION: While there was no statistically significant relationship between BMI and HRV, based on the results of the current study and by previous results (Wolfe & Dennis, 2016; Dennis & Wolfe, 2016) PA and PA intensity appear to have a larger impact on HRV rather than weight status. In terms of improving health, increasing PA should be the focus of college aged adults rather than reducing weight status.