Exercise in Adolescents With Type 1 Diabetes

Regular physical activity is an important part of diabetes management in adolescents with type 1 diabetes (T1D). Increased physical activity has several beneficial effects such as improved lipid profile, insulin sensitivity and quality of life. In addition, a reduced HbA1c is often seen in association to increased physical activity. However, the effect on glycemic control and the acute glycemic response seems to differs between different types of exercise. This issue is poorly studied in adolescents with T1D and the mechanism behind this is not fully understood. The primary aim of this study was to compare the acute effects on glycemia of resistance and two aerobic continuous and intermittent exercise bouts in adolescents with type 1 diabetes. Secondarily, the investigators want to compare the different exercise according to hormonal changes and expression of mRNA in muscle. At a baseline visit the participants was tested for maximal oxygen consumption (pVO2peak) and maximal strength (1-RM). The study participants then performed three exercise bouts and one control session (resting), each on 45 minutes, in a randomized order. Measurement was performed during and after the exercise.

Each subject performed three bouts with 45 minutes of exercise (continuous exercise, intermittent exercise and resistance exercise) in a randomized order. In addition a control session were performed where the subjects sat on a chair for 45 minutes.

Plasma glucose were measured at 5 minutes before and at start of the bouts. Thereafter glucose was measured at 5,10,15,30 and 45 minutes during exercise. In addition glucose were measured at 15, 30, 45 and 60 minutes during the initial recovery period.

Blinded continuous glucose measurement was started when the exercise bouts were finished and were there after used during the next 22 hours (until the next morning at 08:00 am).

Serum samples were collected at baseline and after 15 ,30 ,45 of exercise and after 15 minutes of recovery for later analysis

mRNA levels were analyzed with microarray from muscle biopsies and compared between exercise bouts and baseline.

One biopsy (baseline) were collected approximately one week before the first exercise bout and thereafter one biopsy appr. 60 minutes after each exercise bout.

mRNA levels were analyzed with microarray from muscle biopsies and compared between the exercise bouts.

Heart rate (beats per minute) were monitored by pulse oximetry and compared between the exercise bouts.

Heart rate was monitored continuously during exercise from 5 minutes before start of exercise until the bout was finished (time-point 45 minutes).

Hemoglobin saturation (SpO2 %) was monitored by pulse oximetry and compared between the exercise bouts.

Hemoglobin saturation was measured continuously during exercise from 5 minutes before start of exercise until the bout was finished (time-point 45 minutes).

Cardiac output was measured continuously during exercise from 5 minutes before start of exercise until the bout was finished (time-point 45 minutes).

Inclusion Criteria: Male Type 1 diabetes HbA1c < 65 mol/mol at inclusion Regularly performing physical activity Aged 16-18 years old Exclusion Criteria: Less than 0.5 U/kg in insulin requirements Duration of diabetes less than one year.