Study aim: To assess the relations between anthropometric and cardio-respiratory indices, and aerobic capacity of students, differing in the level of physical activity, under resting and exercise conditions.

Material and methods: A group of 87 male and 75 female students volunteered to participate in the study. Their physical activity was evaluated by Seven-Day Physical Activity Recall questionnaire. Anthropometric (body height and mass, body fat content, BMI and WHR) and physiological indices (heart rate, blood pressure, O₂max, CO₂ and minute ventilation) were recorded. Body fat content was determined using a BIA device; respiratory data were recorded in a cycle ergometer test. The subjects were classified by their O₂max values into ‘high’ or ‘low’ categories, the cut-off values of lower and upper quartiles serving as criteria.

Results: Male and female students expended 10.2 ± 4.6 and 8.4 ± 5.3 kcal/kg/day, respectively, the O₂max amounting to 48.4 ± 6.4 and 41.1 ± 4.7 ml/kg/min, respectively. Subjects having high O₂max had significantly higher energy expenditure on physical activities, fat-free mass, body water content and maximal ventilation, and lower body mass, BMI, body fat content, resting heart rate and diastolic pressure.

Conclusions: When investigating into the relationships between physical activity and physiological features, the latter ought to be related to O₂max rather than to energy expenditure which may depend on other than physiological variables.