IntroductionA healthy lifestyle, including healthy eating, frequent physical activity, abstention from recreational substances, appropriate amounts of sleep and restricted amounts of television and computer time have a positive impact on the development and health of adolescents.The aim of the study was to assess selected aspects of adolescent lifestyle with a focus on rates of physical activity.Materials and methodsThe study material included a questionnaire completed by 304 secondary school students. The answers were analysed with respect to the physical activity of the respondents and then grouped accordingly: group 1 consisted of respondents with a low rate of physical activity, group 2 with a moderate rate of physical activity and group 3 with a high rate of physical activity. Differences in the the percentages of healthy behaviour the groups engaged in was assessed using the Kruskal–Wallis ANOVA on ranks test. Post hoc, a 2-way test with Bonferroni correction was performed. A p value of <0.05 was considered statistically significant for all analyses.ResultsThe recommended number of 4–5 meals a day is consumed mostly by individuals from group 2 (52.94%) and to the least extent by those in group 1 (47.17%). The recommended daily consumption of fruit is mostly reported by respondents from group 3 (39.34%) and the least, by those from group 1 (26.42%). Subjects from group 2 are least likely to drink alcohol, which is harmful for one's health (26.47%); this group also includes the largest number of individuals who do not smoke cigarettes (69.12%). The most favorable behaviour with regards to sleep is displayed by subjects from group 3, in which 10.38% of participants slept for the recommended 8–10 h a day.ConclusionsThe majority of adolescents, regardless of the frequency of physical activity they undertook, had an unhealthy lifestyle. The most favourable lifestyle was led by subjects who performed physical activity between once a week and a few times a month.