The mediating role of adiposity in the longitudinal association between cardiorespiratory fitness and blood pressure in adolescents: LabMed cohort study

Prospective Predictors of Blood Pressure Among African American Men Living with HIV

Little is known about the predictors of blood pressure (BP) among African American men living with HIV. We examined whether age and body mass index (BMI) are associated with higher blood pressure (BP) and whether being married and muscular endurance are associated with lower BP among African American men living with HIV. Second, we examined whether being married moderated the effects of the other predictors on BP. Finally, we examined whether BMI mediated the relationship between muscular endurance and BP. This article is a prospective secondary analysis of data from a randomized controlled trial of a health-promotion intervention for African American men living with HIV. We measured the participants' BP pre-intervention and three, six, and 12 months post-intervention. Generalized estimating equations linear regression analyses examined whether marital status, age, BMI, and muscular endurance predicted BP post-intervention, adjusting for pre-intervention BP and the intervention. Older age, higher BMI, and lower muscular endurance predicted higher BP post-intervention, adjusting for the intervention and baseline BP. Although marital status did not predict post-intervention BP, it moderated the negative effect of higher BMI. The positive relation of BMI to BP was weaker among married men than unmarried men. Muscular endurance had an indirect impact on BP mediated through BMI. Public health efforts targeting older African American men with HIV should focus on increasing muscular endurance in this population to lower BMI as a strategy to reduce cardiovascular disease risk in this population.

The Mediation Role of Fatness in Associations between Cardiorespiratory Fitness and Blood Pressure after High-Intensity Interval Training in Adolescents

BACKGROUND

Low cardiorespiratory fitness (CRF), elevated blood pressure (BP), and high fatness are cardiovascular disease risk factors. It remains unknown how fatness affects the influence of CRF on BP. Therefore, the aim was to examine whether the associations between baseline CRF and HIIT-postintervention resting BP were mediated through fatness in adolescents.

MATERIAL AND METHODS

The sample (n = 64) comprised 28 boys 36 girls aged 16 years. The analysed factors were fitness index- reflecting CRF, body fat mass (BFM), fat mass index (FMI), and body mass index (BMI). Bootstrapped mediation procedures were performed. The mediation analysis was conducted concerning the sex moderation effect.

RESULTS

The mediation effect of sex was confirmed; therefore, mediations models were designed separately for boys and girls. The results showed a statistically significant inverse relationship between baseline CRF and post-intervention systolic blood pressure (SBP) in both sexes (boys: B = -0.603, p = 0.010; girls: B = -0.394, p = 0.037). The relations between CRF and SBP revealed the mediation effect of the BFM and the FMI only in boys.

CONCLUSIONS

Fatness mediated associations between CRF and SBP in boys. Therefore, both CRF and fatness are necessary to maintain positive results of the BP revealed in normal SBP ranges after HIIT.