The researchers note that measurements of the arteries known vascular intima-media thickness (IMT) and elasticity can be used to evaluate atherosclerosis (hardening of the arteries). They explain that data on the effect of cardiorespiratory fitness on these measures of vascular health in adolescence are scarce. Therefore, they conducted a study to examine the association of fitness with aortic and carotid artery IMT and elasticity in adolescents. The aorta is the large artery from the heart that divides into vessels that supply blood to the entire body. The carotid arteries are the arteries in the neck that supply blood to the brain.
Via ultrasound, the researchers measured aortic (449 teens) and carotid (467 teens) IMT and elasticity in 17-year-old adolescents participating in a prospective, longitudinal (a forward-looking study conducted over time) atherosclerosis prevention study known as the Special Turku Coronary Risk Factor Intervention Project. The measures of arterial elasticity were distensibilty and Young’s elastic modulus (YEM) were used as measures of arterial elasticity. Cardiorespiratory fitness (maximum oxygen uptake, mL/kg/min) was measured with a maximal cycle ergometer test. The investigators obtained fitness data on 341 of adolescents with aortic and 355 with carotid ultrasound measures.
The investigators found that fitness was inversely associated with aortic IMT and YEM, meaning that these measurements were better in teens that were physically fit compared to those that were not. The risk of having low aortic distensibility decreased with increasing fitness. The increase in aortic IMT and YEM between ages 11 and 17 years was smaller in adolescents who were fit at age 17 compared with adolescents who had the lowest fitness level. Fitness was not associated with carotid IMT or elasticity. Lifestyle counseling given in the Special Turku Coronary Risk Factor Intervention Project was not associated with fitness.
The authors concluded that fitness was favorably associated with aortic IMT and elasticity in adolescents. No association of fitness with these values in the carotid arteries was found. They noted that their data suggests that fitness in part enhances vascular health in healthy adolescents.
