Detailed investigation of multiple resting cardiovascular parameters in relation to physical fitness

Abstract

Objective: Maximal oxygen consumption at an exercise test (VO₂ -max) is a commonly used marker of physical fitness. In the present study, we aimed to find independent clinical predictors of VO₂ -max by use of multiple measurements of cardiac, respiratory and vascular variables collected while resting.

Methods: In the Prospective study of Obesity, Energy and Metabolism (POEM), 420 subjects aged 50 years were investigated regarding endothelial function, arterial compliance, heart rate variability, arterial blood flow and atherosclerosis, left ventricular structure and function, lung function, multiple blood pressure measurements, lifestyle habits, body composition and in addition a maximal bicycle exercise test with gas exchange (VO₂ and VCO₂ ).

Results: When VO₂ -max (indexed for lean mass) was used as the dependent variable and the 84 hemodynamic or metabolic variables were used as independent variables in separate sex-adjusted models, 15 variables showed associations with p < 0.00064 (Bonferroni-adjusted). Eight independent variables explained 21% of the variance in VO₂ -max. Current smoking and pulse wave velocity (PWV) were the two major determinants of VO₂ -max (explaining each 7% and 3% of the variance; p < 0.0001 and p = 0.008, respectively). They were in order followed by vital capacity, fat mass, pulse pressure, and high-density lipoprotein (HDL)-cholesterol. The relationships were inverse for all these variables, except for vital capacity and HDL.

Conclusion: Several metabolic, cardiac, respiratory and vascular variables measured at rest explained together with smoking 21% of the variation in VO₂ -max in middle-aged individuals. Of those variables, smoking and PWV were the most important.

Keywords: VO2-max; exercise test; physical fitness; pulse wave velocity; smoking.

Figure 1

Relationships between hemodynamic and metabolic variables and VO₂‐max (adjusted for lean mass) when the hemodynamic and metabolic variables were evaluated one by one. The regression coefficient and 95% CIs are given for the sex‐adjusted analyses. a, atrial contraction transmitral filling velocity; AIx, aortic augmentation index; AMBP, ambulatory monitoring of blood pressure; BMI, body mass index; CI, cardiac index; DBP, diastolic blood pressure; e, early transmitral filling velocity; EDV, endothelium‐dependent vasodilatation; EE, energy expenditure; EF, ejection fraction; EIDV, endothelium‐independent vasodilatation; FEV1, forced expiratory volume at 1 s; FMD, flow‐mediated dilatation; HDL, high‐density lipoprotein; HR, heart rate; HRV, heart rate variability; IM‐GSM, echogenicity of the intima‐media complex; IMT, intima‐media thickness; IVRT, isovolumetric relaxation time; IVS, intraventricular thickness; LA, left atrial diameter; LF, low frequency; LF/HF ratio, low‐frequency/high‐frequency ratio; LVEDD, left ventricular end‐diastolic diameter; LVESD, left ventricular end‐systolic diameter; LVMI, left ventricular mass index; PP, pulse pressure; PW, posterior wall thickness; PWV, pulse wave velocity; RHI, reactive hyperaemia index; RI, reflectance index; RQ, respiratory quote; RWT, relative wall thickness; SBP, systolic blood pressure; SDFV, systolic to diastolic blood flow velocity; SI, stroke index; SV/PP‐ratio, stroke volume to pulse pressure ratio; TPRI, total peripheral resistance index; VC, Vital capacity; VCO₂, carbon dioxin production; VO₂, oxygen consumption.

Figure 2

Relationships between VO₂‐max (adjusted for lean mass) and variables were found to be of major importance to explain the variation in VO₂‐max (adjusted for lean mass). VO₂‐max versus current smoking is given in the upper panel. VO₂‐max versus pulse wave velocity (PWV) is in the middle panel and VO₂‐max versus fat mass is given in the lower panel.