Human physical activities may bring potential health benefits. The aim of our study was to compare body composition, lung function and aerobic fitness as a function of age in a cross-sectional study of 277 recreational cyclists (men: n = 163, women: n = 114) and 377 recreational runners (men: n = 239, women: n = 138) aged 20 to 60 years, with a training volume of about 2000 to 4000 km per year for cyclists and 25 to 60 km per week for runners. The survey focused on comparing the values of body composition, lung function and aerobic fitness in dependence on age. The results suggest that recreational cycling and running is associated with a favorable body composition and increased physical fitness, where the percentage of body fat in athletes corresponds to about 70–90% of the population norm, while physical fitness indices, maximum oxygen consumption and maximum exercise performance corresponded at about 140 to 150% of the population norms. The study confirms the assumption that the decrease in physiological functions and/or physical condition with age is much slower in those who participate in recreational sports than in the general nonsports population.