**Background:** Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease with increasing global prevalence, accounting for 5–10% of diabetic patients. Children and adolescents with T1DM face elevated risks of mental health disorders, with depression prevalence two-fold greater than peers in the general population and three-fold greater in adolescents. Health-related quality of life (HRQoL) in young T1DM patients is poor compared to healthy peers. Physical activity (PA) has demonstrated benefits for body composition, insulin sensitivity, glycemic control, and stress reduction, yet children with T1DM often fail to meet recommended PA levels. Diabetes camps have been organized worldwide to promote healthy habits and encourage active lifestyles, but research on their effectiveness for improving PA and HRQoL has yielded contradictory findings. This study aimed to evaluate whether participation in a short-term summer diabetes sports camp, alongside healthy peers with medical supervision, would increase PA levels and improve HRQoL and psychological status in children with T1DM.
**Methods:** This randomized controlled trial recruited 84 children and adolescents with T1DM (aged 7–18 years) from the Endocrine Unit of the 3rd Pediatric Department of Aristotle University of Thessaloniki and outpatient clinics. An a priori power analysis (alpha=0.05, effect size f=0.25) indicated a required sample size of 36 participants. Eligible participants had T1DM for at least one year, maintained a stable insulin regimen, and had no other conditions affecting exercise ability. Participants were randomly assigned via www.randomizer.org to an intervention group (n=42) attending a 10-day summer diabetes sports camp, or a control group (n=42) continuing their daily routine. The intervention included 6 hours of daily PA (3 hours morning, 3 hours afternoon) with activities including swimming, sailing, diving, climbing, football, tennis, volleyball, basketball, handball, ping pong, canoeing, archery, and athletics, plus educational sessions on PA's role in glycemic control and disease management. At baseline and post-intervention, participants completed the Godin-Shephard Leisure-Time Physical Activity Questionnaire, Life Satisfaction Assessment Scale (Cronbach's alpha=0.30), Rosenberg Self-Esteem Scale (Cronbach's alpha=0.76), CES-D depression scale (Cronbach's alpha=0.64), and the Health Action Process Approach (HAPA) questionnaire assessing health status, intention to change behavior, and activity planning (Cronbach's alphas 0.64–0.85). Statistical analysis used two-way repeated measures ANOVA with SPSS 25.0, with two-tailed p<0.05 considered significant.
**Key Results:** Baseline characteristics showed no significant differences between groups. Mean BMI was 20.15 (SD=3.36) for intervention and 20.15 (SD=4.39) for control. HbA1c levels were above recommended targets for both groups. For physical activity, no significant interaction was found (F1,82=0.94, p>0.05, η²=0.01) and no main effects for time or group. For quality of life indicators: life satisfaction showed no significant interaction (F1,82=0.05, p>0.05, η²=0.001); self-esteem showed no significant interaction (F1,82=2.78, p>0.05, η²=0.03); depression showed no significant interaction (F1,82=0.06, p>0.05, η²=0.001). For HAPA variables: health status (F1,82=0.95, p>0.05, η²=0.01), changes in health (F1,82=0.22, p>0.05, η²=0.03), relationship of health with everyday life (F1,82=0.87, p>0.05, η²=0.00), intention (F1,82=0.40, p>0.05, η²=0.01), activities planning (F1,82=0.06, p>0.05, η²=0.001), and planning to address difficulties (F1,82=0.01, p>0.05, η²=0.00) all showed no significant interactions. A statistically significant main effect for groups emerged only for changes in health (F1,82=4.67, p<0.05, η²=0.05), and a significant main effect for time only for activity planning (F1,82=6.01, p<0.05, η²=0.07).
**Clinical Implications:** This study demonstrates that a 10-day diabetes sports camp with intensive daily PA does not produce immediate, measurable improvements in PA levels or HRQoL dimensions in children and adolescents with T1DM. The null findings suggest that stable psychological traits such as self-esteem and depression require longer intervention periods or specific targeted strategies (e.g., behavioral activation, cognitive restructuring) to change. The lack of follow-up measurements is a significant limitation, as prior research has shown delayed positive effects on PA emerging 3–6 months post-camp. The authors recommend that future interventions should either extend camp duration or implement multiple camps throughout the year to allow health-related behaviors to become habitual. Additionally, incorporating specific behavior change techniques targeting attitudes, norms, and self-efficacy may be necessary to produce favorable intentions toward healthy behavior. Despite the null results, diabetes camps remain valuable for providing safe environments for peer interaction, medical supervision, and education about disease management. Future research should include longer follow-up periods and measure more situational dimensions of QoL (e.g., vitality) rather than stable traits to better capture intervention effects.