Cardiorespiratory Fitness is Associated with Estimates of Myocardial Perfusion: Influence of Age and Sex

Abstract

Cardiorespiratory fitness (CRF) and the subendocardial viability ratio (SEVR) decline with age and predict future cardiovascular disease (CVD) events in a sex-dependent manner. However, the relation between CRF and SEVR in apparently healthy males and females across the age span is largely unknown. We hypothesized higher CRF is associated with greater SEVR in older females, but not males. Two hundred and sixty-two (126M/136F, age range 20-84 yr) participants underwent measures of CRF (maximal O2 consumption [VO2max]) and SEVR (pulse wave analysis, PWA). A 2-way analysis of variance (ANOVA) was used to examine differences in baseline characteristics between younger (<45 y) and middle-aged and older (MA/O, ≥45 y) males and females. Bivariate correlations assessed the relation between CRF, SEVR, and age in males and females. Partial correlations adjusted for CVD risk factors and medications. MA/O females had the lowest CRF and SEVR compared to all other groups (p<0.05, both). SEVR was negatively correlated with age (r=-0.29) and positively correlated with CRF (r=0.53) in females (p<0.05, both) which persisted after controlling for CVD risk factors and medications (p<0.05, all). SEVR was correlated with CRF in males only after adjusting for CVD risk factors and medications (r=0.26, p<0.05). These findings collectively demonstrate higher CRF is associated with greater SEVR in males and females after adjusting for CVD risk factors and medications, therefore highlighting subtle sex-specific nuances which warrant further investigation.