MODERATION AND MEDIATION OF BODY COMPOSITION ON THE RELATIONSHIP BETWEEN PHYSICAL ACTIVITY AND ARTERIAL HEALTH
Brantley K. Ballenger, Sydni L. Carter, Grant Norman, Stamatis Agiovlasitis, FACSM. Mississippi State University, Mississippi State, MS.
BACKGROUND: Cardiovascular disease is the leading cause of death in the United States. Physical activity (PA) levels and body fat percentage (%BF) contribute to cardiovascular disease risk, through increased arterial stiffness. However, the pathway of this relationship is not known. This study examined whether %BF moderates or mediates the relationships between PA or sedentary behavior levels with arterial stiffness. METHODS: Forty adults (19 men; age 27±10 yrs.) had carotid-femoral pulse wave velocity (CF-PWV) measured by applanation tonometry and %BF by bioelectrical impedance. Participants then wore a triaxial accelerometer on the non-dominant hip for 7 days to measure PA and sedentary behavior. Accelerometer data were scored with the Freedson cut points (Sedentary: ≤199 counts/min; Light ≤2690 counts/min; Moderate-to-vigorous: ≥2691 counts/min), allowing determination of percentage of time spent in sedentary (%Sedentary), light (%Light), and moderate-to-vigorous (%MVPA) PA levels. RESULTS: Pearson’s correlations showed significant associations between age, %BF, CF-PWV, and %Sedentary (r=.317-.732, p<.05). However, %Light and %MVPA were not significantly associated with CF-PWV. The mediation analysis showed significant total effects of %Sedentary (β=.34, p=.034) and age (β=.73, p<.001) on CF-PWV. %BF partially mediated the relationship between age and CF-PWV (β=.63, p<.001), and fully mediated the relationship between %Sedentary and CF-PWV (β=.16, p=.29). Moderation analysis showed that the interaction of %BF and %Sedentary (R2=.31, p=.004), %Light (R2=.28, p=.007) and %MVPA (R2=.36, p=.001) significantly predicted CF-PWV. Furthermore, %BF significantly moderated the effect of %MVPA on CF-PWV (β=-.26, p=.049), but not %Sedentary or %Light. The effect of %MVPA on CF-PWV was greatest for those who were high (+1 SD) in %BF (β=-.60, p=.02), and moderate for those at the mean %BF (β=-.33, p=.04). CONCLUSION: %BF mediates the relationship between PA levels and arterial stiffness. Therefore, limiting sedentary behavior-by engaging in greater amounts of light or moderate-to-vigorous PA-can reduce %BF. Reductions in %BF may lead to decreased arterial stiffness. Funding: Mississippi State University Office of Research and Economic Development and I’m An Athlete Foundation
Ballenger, BK; Carter, SL; Norman, G; and Agiovlasitis, S
"MODERATION AND MEDIATION OF BODY COMPOSITION ON THE RELATIONSHIP BETWEEN PHYSICAL ACTIVITY AND ARTERIAL HEALTH,"
International Journal of Exercise Science: Conference Proceedings: Vol. 16:
2, Article 143.
Available at: https://digitalcommons.wku.edu/ijesab/vol16/iss2/143