FERREIRA, I., J. W. R. TWISK, C. D. A. STEHOUWER, W. VAN MECHELEN, and H. C. G. KEMPER. Longitudinal Changes in V̇O2max: Associations with Carotid IMT and Arterial Stiffness. Med. Sci. Sports Exerc., Vol. 35, No. 10, pp. 1670–1678, 2003.
Purpose: High levels of cardiorespiratory fitness (V̇O2max) are associated with reduced risk of cardiovascular morbidity and mortality. However, little is known to what extent longitudinal changes in V̇O2max affect arterial wall thickness and stiffness, i.e., two major risk factors for cardiovascular disease. We therefore investigated the relationship between changes in V̇O2max from adolescence (13–16 yr) to adulthood (age 36) and from young adulthood (21–32 yr) to age 36, and carotid intima-media thickness (IMT) and stiffness of the carotid, femoral, and brachial arteries, at age 36.
Methods: Analyses of changes in V̇O2max from adolescence to age 36 consisted of 154 subjects (79 women), and from young adulthood to age 36 consisted of a subpopulation of 118 subjects (62 women). Throughout the years, V̇O2max was measured directly with a maximal running test on a treadmill. When the subjects had the mean age of 36, carotid IMT and large artery stiffness (distensibility and compliance coefficients) were assessed noninvasively by ultrasound imaging methods.
Results: Longitudinal changes in V̇O2max were not significantly associated with carotid IMT. Changes in V̇O2max were inversely and significantly associated with large artery stiffness. These associations were not uniform throughout the arterial tree, being stronger and independent of changes in other risk factors in the muscular (brachial and femoral) arteries but dependent on and possibly mediated by concomitant changes in HDL cholesterol and body weight in the elastic carotid artery.
Conclusion: Increases in V̇O2max that occur from adolescence up to age 36 are associated with less arterial stiffness. Improving V̇O2max by increasing physical activity levels may therefore contribute to a reduction in mortality from cardiovascular disease through decreasing arterial stiffness.
High levels of cardiorespiratory fitness (5,25) and changes from unfit to fit states (6,10) are associated with reduced cardiovascular morbidity and mortality. However, little is known to what extent this is related to the effects of cardiorespiratory fitness on arterial wall thickness and stiffness, i.e., two major contributory factors to cardiovascular morbidity and mortality (2,13,24).
Previous cross-sectional studies have supported the concept that high cardiorespiratory fitness is inversely and independently associated with carotid intima-media thickness (IMT) (11,23) and its progression (18), at least in men, and with reduced arterial stiffness (11,26,33). However, analyses from single time-point estimates, as in these studies, assume a homogenous development of cardiorespiratory fitness with age throughout the population, whereas cardiorespiratory fitness levels may vary longitudinally due to changes in lifestyle (e.g., physical activity (PA) and smoking) (4,17) and/or development of subclinical disease. One way of analyzing this issue more completely is to evaluate the impact of changes in cardiorespiratory fitness on large artery properties. In this regard, some trials have shown that increasing cardiorespiratory fitness through physical training programs (1–3 months) reduces arterial stiffness (8,30), but not carotid IMT (31), in sedentary healthy men. However, it is not known whether these effects also occur in the context of observed longitudinal rather than “experimental” (trial-associated) changes in cardiorespiratory fitness.
Therefore, what needs to be investigated is whether changes in cardiorespiratory fitness throughout life affect carotid IMT and arterial stiffness, and whether these effects are similar in men and women. A further essential question is whether the association between changes in cardiorespiratory fitness levels and arterial stiffness differs between elastic (e.g., the carotid) and muscular (e.g., the femoral and brachial) arteries (14,26). In addition, the impact of changes in daily PA levels on cardiorespiratory fitness and large artery properties needs to be clarified, because any such association would have important implications not only for understanding pathophysiological mechanisms but also for public health policies (i.e., lifestyle interventions) directed at increasing cardiorespiratory fitness.
In the Amsterdam Growth and Health Longitudinal Study (AGAHLS), extended follow-up of cardiorespiratory fitness and PA levels from adolescence to adulthood, and large artery properties measured at age 36 in both men and women, provide an opportunity to study these issues. We therefore investigated the relationships between changes in cardiorespiratory fitness [from adolescence (13–16 yr) to adulthood, and from young adulthood (21–32 yr) to adulthood], and carotid IMT and stiffness of the carotid, femoral, and brachial arteries, in men and women aged 36. We then investigated the associations of changes in PA levels with changes in cardiorespiratory fitness and large artery properties.