Relationships between Obesity, Cardiorespiratory Fitness, and Cardiovascular Function
Kade Davison1, Stefan Bircher, Alison Hill
1Nutritional Physiology Research Centre and ATN Centre for Metabolic Fitness, School of Health Sciences, University of South Australia, SA 5001, Australia.
Insights
Obesity impairs blood vessel function, specifically endothelial vasodilatator function. Low cardiorespiratory fitness (CRF) is linked to reduced elasticity in large arteries, highlighting distinct impacts on cardiovascular health.
Area of Science:
- Cardiovascular physiology
- Metabolic health
- Exercise science
Background:
- Obesity and low cardiorespiratory fitness (CRF) are independent risk factors for cardiovascular disease (CVD) mortality.
- Understanding their distinct effects on arterial function is crucial for preventative strategies.
Purpose of the Study:
- To investigate the relationship between CRF, body fatness, and markers of arterial function.
- To differentiate the impacts of obesity and CRF on vascular health.
Main Methods:
- Comparison of obese and lean individuals using DXA for body composition and predicted V˙O2max for CRF.
- Assessment of blood pressure (BP), flow-mediated dilation (FMD), and arterial compliance (AC) via radial artery tonometry.
Main Results:
- Obese individuals exhibited higher body fat and abdominal fat percentages compared to lean individuals.
- Obese participants showed significantly lower FMD, indicating impaired endothelial function.
- Arterial compliance (AC) in large arteries was positively associated with CRF but not with body fatness.
Conclusions:
- Obesity distinctly impairs endothelial vasodilatator function (FMD), potentially contributing to arterial and metabolic dysfunction.
- Low CRF is associated with reduced elasticity in large arteries, possibly increasing aortic afterload.
- These findings underscore the separate roles of obesity and CRF in influencing blood vessel health.
Abstract:
Background. Obesity and low cardiorespiratory fitness (CRF) have been shown to independently increase the risk of CVD mortality. The aim of this study was to investigate the relationship between CRF, body fatness and markers of arterial function. Method and Results. Obese (9 male, 18 female; BMI 35.3 ± 0.9 kg·m(-2)) and lean (8 male, 18 female; BMI 22.5 ± 0.3 kg·m(-2)) volunteers were assessed for body composition (DXA), cardiorespiratory fitness (predicted V˙O2max), blood pressure (BP), endothelial vasodilatator function (FMD), and arterial compliance (AC) (via radial artery tonometry). The obese group had more whole body fat and abdominal fat (43.5 ± 1.2% versus 27.2 ± 1.6%; P < .001 and 48.6 ± 0.9% versus 28.9 ± 1.8%; P < .001, resp.), and lower FMD (3.2 ± 0.4% versus 5.7 ± 0.7%; P < .01) than the lean subjects, but there was no difference in AC. AC in large arteries was positively associated with CRF (R = 0.5; P < .01) but not with fatness. Conclusion. These results indicate distinct influences of obesity and CRF on blood vessel health. FMD was impaired with obesity, which may contribute to arterial and metabolic dysfunction. Low CRF was associated with reduced elasticity in large arteries, which could result in augmentation of aortic afterload.
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