It has been widely indicated that several pathological conditions depend upon concomitant risk factors rather than a unique one and that also the putative protective factors do not act alone. For these reasons it could be useful to consider subjects that present sufficiently homogeneous lifestyles (i.e. nutrition and physical activity). We carried out an investigation in a free-living community in order to clarify the possible correlations and differences among plasma metabolic and antioxidant markers in non-agonistic athletes. When subjects were divided in two main groups according to age (35-44 and 45-54 years) without considering the activity they performed, Duncan's analysis of variance revealed that they showed similar characteristics and only triglyceride levels were different. A clear negative correlation was found between vitamin E and VO2max in both age groups, a negative correlation was also found between CoQ10 and VO2max in the younger subjects and finally CoQ10 and vitamin E were also positively correlated in this first group. It appears, therefore, that people with a higher aerobic capacity have lower circulating levels of antioxidants.