Children in School

The goal of this clinical trial is to assess the health-related effects of an exercise intervention in children aged 5-8 years. Main research questions: * Does a municipality-driven exercise intervention improve physical activity levels in children? * Does a municipality-driven exercise intervention improve sleep parameters in children? * Does a municipality-driven exercise intervention improve eating behaviors in children? * Does a municipality-driven exercise intervention improve quality of life in children? Study Design: Participants will be assigned to either: * Intervention group: Attend 1-2 weekly sessions of 45-60 minutes of child-friendly exercise for 1 year. * Control group: Receive no intervention. Data Collection: Participants will: * Complete questionnaires at baseline, and at 1-year, 3-year, and 5-year follow-ups. * Wear accelerometers for 7 consecutive days at baseline, and at 1-year, 3-year, and 5-year follow-ups.