Short Sprints during Exercise Reduce Exercise-Mediated Hypoglycaemia in Type 1 Diabetes in a Real-Life Setting

Background: Short sprints have been shown to prevent exercise induced hypoglycaemia in controlled laboratory settings. Using a randomised controlled study design, we tested the hypothesis that incorporating sprinting into moderate intensity exercise can reduce the incidence of exercise mediated hypoglycaemia in individuals with T1D in a real-life setting.

Methods: Individuals with T1D, diagnosed for >1 year, aged 14-35 years, with an HbA1c of ≤9% were recruited into a prospective randomised controlled cross over study. Participants completed three 14-day periods in random order. In one period participants adhered to their usual exercise management (control period), in the other 2 periods, participants additionally incorporated 10s (every 20 mins) or 4s sprints (every 2 mins) into moderate intensity exercise. Outcome measures included the incidence of hypoglycaemia (defined as sensor glucose readings <3.1mmol/L for ≥ to 20 minutes) over the 14-day period; and percent time spent <3.1mmol/L and <3.5mmol/L. CGM data were analysed using a mixed model approach.

Results: 24 participants completed the study, performing a total of 420 exercise episodes. The 10s period was associated with fewer hypoglycaemia events (<3.1mmol/L) than the control period (adjusted incidence rate ratio of 0.67, 95% CI 0.46-0.98: p=0.04), with a hypoglycaemia incidence rate of 0.40 (95% CI 0.26-0.55), 0.33 (95% CI 0.21-0.45) and 0.28 (95% CI 0.17-0.38) events per day in the control, 4s and 10s periods respectively. The 10s period was associated with a reduction in time spent <3.5mmol/L (control vs. 10s period, 3.1% vs. 2.1%, p=0.03) and time spent <3.1mmol/L (control vs.10s period, 1.9% vs. 1.2%, p= 0.03) compared to the control period. There was no increase in nocturnal hypoglycaemia during the sprinting periods.

Conclusion: In a real-life setting the inclusion of 10s sprints into moderate intensity exercise reduces the incidence of hypoglycaemia, without increasing the risk of nocturnal hypoglycaemia.