Exercise training and physical activity (PA) have substantial vascular and cardiac health benefits. Ikaria Island has been recognised as having one of the highest longevity rates worldwide and a high percentage of healthy ageing. We examined the relationship between endothelial function and levels of habitual PA to evaluate the factors related to healthy ageing in this population.The study was conducted on a subgroup population of the IKARIA study consisting of 185 middle-aged (40-65 years) and 142 elderly subjects (66-91 years). Endothelial function was evaluated by ultrasound measurement of flow-mediated dilatation (FMD). PA was evaluated using the shortened version of the self-reported International Physical Activity Questionnaire (IPAQ). Subjects in the low PA group (<500 MET/ min/week) were considered as physically inactive and the rest as active.In the overall study population FMD was inversely associated with age (r=-0.24, p<0.001) and middle-aged subjects had higher FMD compared with the elderly (6.26 ± 3.31% vs. 5.21 ± 2.95%, p=0.003). Multiple linear regression analysis revealed that among middle-aged subjects the physically active had higher FMD compared with the physically inactive. Physically active subjects in the middle-aged group showed higher FMD compared with the physically active elderly (p=0.008). However, there was no difference in FMD values between middle-aged inactive subjects and the elderly physically active (p=NS).The present study revealed that increased PA was associated with improved endothelial function in middle-aged subjects and that PA in elderly subjects can ameliorate the devastating effects of ageing on arterial wall properties.