Ectional study enrolled attendees of a health screening program between September 2002 and November 2010. Linear regression models included the metabolic equivalents achieved during an exercise treadmill stress test as the dependent variable and adjusted for self-reported SES parameters (level of education, occupational status, financial strain and a combined variable), cardiovascular risk factors, as well as to multiple potential confounders. Results Data on 8471 individuals (5463 men and 3008 women) with a mean (SD) age of 44 (11) years were collected. We found a statistically significant difference in mean exercise capacity between the categories of SES, especially for the level of education and occupation, when adjusted for age, sex, cardiovascular risk factors, SES variables and multiple confounders. Conclusions Multiple factors affect CRF in apparently healthy screened individuals. When adjusted for those factors, SES correlates with CRF even within a more specific highly educated cohort....