# Mediative role of body mass index in cardiorespiratory fitness-associated vascular remodeling in youth

## TL;DR

Higher cardiorespiratory fitness in children is linked to healthier artery changes, which can counteract some negative effects of higher BMI.

## Contribution

This study reveals how BMI mediates the relationship between cardiorespiratory fitness and vascular remodeling in youth.

## Key findings

- Higher CRF (VO2peak) is directly linked to increased carotid artery intima-media thickness and diameter in girls.
- BMI mediates CRF's indirect effects, reducing artery thickness and diameter while mitigating BMI-related vascular stress.
- CRF promotes uniform arterial remodeling and balanced hemodynamics, counteracting adverse effects of higher BMI.

## Abstract

Data on fitness-associated arterial remodeling in children is limited. We assessed the relation between cardiorespiratory fitness (CRF) and intima-media thickness (IMT), diameter, IMT:diameter-ratio (IDR), and tensile stress of the common carotid artery (CCA) in 697 healthy German schoolchildren. Further, we explored how body mass index (BMI) may influence these associations.

We measured the vascular parameters with a high-resolution ultrasound device. We determined CRF using the FITNESSGRAM® PACER test and calculated each child’s allometrically scaled peak oxygen uptake capacity (VO2peak).

VO2peak, reflecting CRF, showed positive direct effects on IMT (girls: p < 0.001; boys: p = 0.02) and diameter in girls (p < 0.001). Considering BMI as a mediator, higher CRF was indirectly linked to decreases in IMT (girls: p = 0.04; boys: p = 0.02) and diameter (both p < 0.001), reflecting a competitive mediation. CRF indirectly mitigated the BMI-associated decrease in IDR (both p < 0.001) and increase in tensile stress (both p < 0.001) without affecting any of these parameters directly.

CRF appears to be linked to uniform arterial remodeling with balanced hemodynamics and to further alleviate BMI-associated, potentially adverse vascular alterations, highlighting its significant role in cardiovascular health in youth.

Data on CRF-associated arterial remodeling in youth is limited.Higher VO2peak, reflecting higher CRF, was positively associated with IMT in girls and boys and diameter in girls. These direct effects were counteracted by the indirect BMI-mediated effect of CRF on IMT and diameter, reflecting a competitive mediation.A higher CRF indirectly mitigated the BMI-associated decrease in IDR and increase in tensile stress without directly affecting any of these parameters.Our findings indicate homogenous remodeling and balanced hemodynamics with increasing CRF—and opposite effects with increasing BMI.

Data on CRF-associated arterial remodeling in youth is limited.

Higher VO2peak, reflecting higher CRF, was positively associated with IMT in girls and boys and diameter in girls. These direct effects were counteracted by the indirect BMI-mediated effect of CRF on IMT and diameter, reflecting a competitive mediation.

A higher CRF indirectly mitigated the BMI-associated decrease in IDR and increase in tensile stress without directly affecting any of these parameters.

Our findings indicate homogenous remodeling and balanced hemodynamics with increasing CRF—and opposite effects with increasing BMI.