The objective of this study is to test whether an individualized carbohydrate intake based on weight and pre physical activity glucose level is more effective than usual camp care to improve glucose control in children and adolescents engaging in team sports (basketball, soccer, hockey) during a summer camp.

At the enrollment interview, in addition to collecting patient's information (age, sex, diabetes duration, recent A1c, type of treatment, insulin doses body weight, concomitant diseases, diabetes complications and history of severe hypoglycemia), a continuous glucose monitoring system (FreeStyle Libre) will be installed by a nurse. At least, eight sports sessions per participant are planned for this study. In a randomized order, the individualized carbohydrate intake will be applied during at least 4 interventions sport sessions while at least 4 with matching types of sports will be used as control sessions. Two sport sessions are routinely scheduled at the camp each day; from 9h:30 to 10h:30 and from 11h:00 to 12h:00. For intervention sessions that involve individualized carbohydrate intake, the FreeStyle Libre will be scanned 0-10 minutes before the start of the team sport. Carbohydrates will then be given in the amount of 0.5g/kg for glucose levels between 4.5 to 7.0 mmol/L and 0.25g/kg for glucose levels between 7.1 to 10.0 mmol/L and none will be given if glucose levels are between 10.1 and 15.0 mmol/L. When glucose levels are below 4.5 mmol/L or above 15.0 mmol/L, the camp staff will take care of hypoglycemia/hyperglycemia treatment. During control sessions, as per camp routine care, there will be no measurement of glucose levels before the start of physical activity.

Inclusion Criteria:

1. Males or females between the 7 and 16 years of old.
2. Clinical diagnosis of type 1 diabetes for at least 6 months.
3. Using continuous subcutaneous insulin infusion therapy or multiple daily injections.
4. HbA1c ≤ 12.0%.
5. Practicing team sports (soccer, basketball, hockey, tennis) at the summer camp.

Exclusion Criteria:

1. Clinically significant nephropathy, neuropathy or retinopathy as judged by the investigator.
2. Severe hypoglycemic episode within two weeks of inclusion in the study.
3. Using the Medtronic 670G Insulin Pump as a treatment Mode
4. Current use of oral glucocorticoid medication (except low stable dose according to investigator judgement). Stable doses of inhaled steroids are acceptable.
5. Acute disease in the last 3 months that would affect ability to do physical activity.
6. Other serious medical illness likely to interfere with study participation or with the ability to complete the exercise periods by the judgment of the investigator (e.g. orthopedic limitation).