Purpose. The aim of the study was to evaluate the aerobic capacity and energy expenditure of folk dancers. Methods. The aerobic capacity (VO2max) of four male and four female folk dancers was measured by an incremental treadmill test and energy expenditure was assessed by the linear relationship between heart rate and oxygen uptake as based on indirect calorimetry. Results. The dancers presented good aerobic capacity (VO2max), with men achieving values of 51.8 ± 7.39 ml ∙ kg-1 and women 43.43 ± 3.81 ml ∙ kg-1. Steady-state heart rate during folk dancing was 167.8 ± 16.68 b ∙ min-1 (85.0% ± 8.68% HRmax) for men and 178.3 ± 5.62 b ∙ min-1 (91.0% ± 3.83% HRmax) for women, with energy expenditure at 14.54 ± 2.09 kcal · min-1 and 10.08 ± 2.03 kcal · min-1, respectively. Conclusions. The exercise intensity performed during folk dancing is close to the threshold of decompensated metabolic acidosis. Folk dancing can be quantified as a difficult (for men) and very difficult (for women) form of physical activity; dancers should be physically well-prepared for the high exercise intensity present in folk dancing.