Effects of moderate-to-vigorous intensity physical activity on overnight and next-day hypoglycemia in active adolescents with type 1 diabetes

Abstract

Objective: Physical activity (PA) provides many benefits to adolescents with type 1 diabetes; however, these individuals tend to have lower fitness and PA levels than their disease-free counterparts. The purpose of this study was to examine the acute temporal associations between moderate-to-vigorous intensity PA (MVPA) and hypoglycemia (continuous glucose monitor [CGM] reading ≤70 mg/dL).

Research design and methods: Nineteen participants (53% females) 14-20 years old with type 1 diabetes were recruited. Participant fitness was evaluated via indirect calorimetry using a maximal exercise test; body composition was measured using air displacement plethysmography. An accelerometer was worn continuously (3-5 days) and acceleration data used to estimate MVPA (minutes per day). Blood glucose values were simultaneously tracked using CGM. Controlling for sex, percent body fat (%BF), fitness, and concurrent MVPA, the likelihood of nighttime and next-day hypoglycemia due to MVPA was examined using logistic regression.

Results: Participants were of average fitness (females: 43.9 mL/kg/min; males: 49.8 mL/kg/min) and adiposity (females: 26.2%; males: 19.2%); 63.2% met the U.S. federal guideline of accumulating 60 min/day of MVPA. Hypoglycemia was 31% more likely in those who accumulated 30 min/day more MVPA in the previous afternoon than those with less (95% CI 1.05-1.63; P = 0.017).

Conclusions: The results suggest that participating in afternoon MVPA increases the risk of overnight and next-day hypoglycemia, independent of sex, %BF, fitness, and concurrent MVPA. While promoting PA as a healthy behavior, it is important to educate adolescents with type 1 diabetes on prevention of hypoglycemia following PA.

Figure 1

Heat map of average physical activity patterns of all participants. ^aTimes based on average activity of all participants (n = 19).