Exercise Training Duration and Intensity Are Associated With Thicker Carotid Intima-Media Thickness but Improved Arterial Elasticity in Active Children and Adolescents

Abstract

Even though exercise generally has a positive effect on health, intensive exercise can have adverse effects on the vascular system of adults. This study aimed to investigate the association between training duration and intensity and vascular structure and function in 427 physically active children and adolescents (14.0 ± 1.94 years). In this study, we examined carotid intima-media thickness (cIMT), carotid diameter, and cIMT:diameter-ratio as parameters of carotid arterial structure and arterial compliance (AC), stiffness index β (β), elastic modulus (Ep), and carotid pulse wave velocity (PWVβ) as parameters of carotid arterial function with high-resolution ultrasound. We collected central systolic blood pressure (cSBP) and aortic pulse wave velocity (aPWV) as parameters of central arterial stiffness with an oscillometric device. We used the MoMo Physical Activity Questionnaire to record training duration and intensity. Training duration (p = 0.022) and intensity (p = 0.024) were associated with higher cIMT. Further, training duration was associated with lower central arterial stiffness (cSBP: p = 0.001; aPWV: p = 0.033) and improved AC (p < 0.001). Higher training intensity was related to improved AC (p < 0.001) and larger carotid diameter (p = 0.040). Boys presented thicker cIMT (p = 0.010), improved AC (p = 0.006), and lower central arterial stiffness (cSBP: p < 0.001; aPWV: p = 0.016) associated with higher training duration. Girls presented improved AC (p = 0.023) and lower Ep (p = 0.038) but higher β (p = 0.036) associated with higher training duration. Only boys demonstrated thicker cIMT (p = 0.016) and improved AC (p = 0.002) associated with higher training intensity. A quintile analyses of the training duration revealed thicker cIMT of children and adolescents in Q1 and Q5 than that in Q4 and Q5. Besides, Q1 showed lower cSBP compared to Q4 and Q5. Regarding training intensity, Q5 had thicker cIMT than Q2 and Q3. Although a higher training load is associated with thicker cIMT, the common carotid artery is also more elastic. This suggests that a higher training load leads to a functional adaptation of the carotid artery in youth.

Preventative interventions that target cardiovascular dysfunction in children and young people: a systematic review of their effectiveness and an investigation of sexual dimorphism

“…In non-obese children, all 7 studies of exercise intervention, ranging from resistance training to active dance-based video game use, which measured FMD demonstrated significant increases in endothelial function [28][29][30][31][32][33]. Of the 9 studies [34][35][36][37][38][39][40][41][42] which measured CIMT, 2 (22%) found a decrease in IMT with exercise training, one with shuttle run training [34] and one finding that an increase in intensity and duration of any form of exercise resulted in improvements [35]. Results were inconsistent in the 12 studies, which measured PWV, with 6 (50%) [10,12,35,[43][44][45] finding reductions in arterial stiffness and 6 (50%) [39-42, 46, 47] finding no differences after the introduction of the exercise intervention.…”

“…Of the 9 studies [34][35][36][37][38][39][40][41][42] which measured CIMT, 2 (22%) found a decrease in IMT with exercise training, one with shuttle run training [34] and one finding that an increase in intensity and duration of any form of exercise resulted in improvements [35]. Results were inconsistent in the 12 studies, which measured PWV, with 6 (50%) [10,12,35,[43][44][45] finding reductions in arterial stiffness and 6 (50%) [39-42, 46, 47] finding no differences after the introduction of the exercise intervention. One study examined central retinal arteriolar and venular vessel diameters as early markers of vascular dysfunction and found that these reduced after an 18 month school-based physical activity programme [48].…”

“…Of the included studies, 6292 (40%) of the participants were female with 70 studies (95%) including both boys and girls in their study design. However, only 6 (8%) of these studies provided data for girls and boys separately, enabling assessment of sexual dimorphism in response to the intervention [28,30,33,35,38,59]. In terms of sex differences, baseline artery diameter was reported to be different between boys and girls [33].…”

“…and an increase in FMD after moderate to vigorous physical activity was only detected when the absolute FMD value was adjusted for baseline diameter at rest. One study of 427 children and adolescents (14.0 ± 1.4 years) found that physical activity resulted in different effects in boys and girls, with increased training duration associated with increased IMT with increased arterial compliance and reduced arterial stiffness in boys, whereas only arterial compliance was affected in girls [35]. Of note, baseline arterial diameter was higher in boys compared to girls [35].…”

“…One study of 427 children and adolescents (14.0 ± 1.4 years) found that physical activity resulted in different effects in boys and girls, with increased training duration associated with increased IMT with increased arterial compliance and reduced arterial stiffness in boys, whereas only arterial compliance was affected in girls [35]. Of note, baseline arterial diameter was higher in boys compared to girls [35]. Bond et al reported that high intensity exercise increased FMD and reduced oxidative stress, as well as providing high rates of enjoyment of the intervention in both girls and boys.…”