Cardiorespiratory fitness is associated with estimates of myocardial perfusion: influence of age and sex.

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 in males. Two-hundred sixty-two (126 M/136 F, age range 20-84 yr) participants underwent measures of CRF (maximal O ₂ consumption, V̇o _2max ) and SEVR (pulse wave analysis, PWA). A two-way analysis of variance (ANOVA) was used to examine differences in baseline characteristics between younger (<45 yr) and middle-aged and older (MA/O, ≥45 yr) 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 with 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) that 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 that warrant further investigation. NEW & NOTEWORTHY Cardiorespiratory fitness (CRF) and the subendocardial viability ratio (SEVR) are independent predictors of mortality and decline with age. However, the sex-specific relationship between CRF and SEVR with aging in adult males and females is unknown. Our findings demonstrate higher CRF is associated with greater age-related SEVR in males and females, after adjusting for traditional cardiovascular disease (CVD) risk factors and medications. However, subtle sex-related nuances exist in the relationship between SEVR and CRF that require further investigation.