RESUMO
Background During the COVID-19 pandemic, school closures caused destructive changes in student weight status, eating habits, screen exposure, sleep patterns, psychological responses, and activity behaviors. Despite the end of the lockdown and reopening of schools, the long-term effects of quarantine on the lifestyle and weight status of children and adolescents remain unknown. On the other hand, there is a chance that these negative changes become more prominent during extended school holidays such as summer breaks. This study aimed to determine the long-term effects of the lockdown on the weight status and lifestyle of children and adolescents after the eighth wave of the disease in Iran.Method This descriptive cross-sectional study was conducted from April to May 2022. The target population comprises one hundred students aged between 10 and 16 years. Our study obtained students' weight and height data from records maintained by school principals or sports teachers before and after the quarantine period. The BMI z score (zBMI) was calculated for each time point. The researchers also provided a questionnaire to collect the students’ demographic and lifestyle status changes during school closures.Results We found that the zBMI increased significantly from − 0.02 ± 1.64 to 0.36 ± 1.12, and the statistics of the overweight and obese population increased by 3% during quarantine (P ≤ 0.05). These changes were more pronounced in males and students aged 14–16 years. We also found that eating habits, sleep time, sleep patterns, screen time, and physical activity had significant negative changes during quarantine, and a significant increase in zBMI was observed among students who experienced negative eating behaviors, altered sleep patterns, and decreased physical activity during school closures. Conclusion: As prolonged school closures due to the COVID-19 lockdown aggravated students’ health and lifestyle status, our findings can aid in proper planning to establish an appropriate framework for the diet, physical activity, and sleep quality of students during extended school closures.