Can short sprints during moderate intensity exercise reduce the incidence of exercise mediated hypoglycaemia in individuals with type 1 diabetes?

Abstract

Background: Short sprints have been shown to reduce exercise induced hypoglycaemia in controlled laboratory settings. This study tested the hypothesis that incorporating sprinting into moderate intensity exercise can reduce the incidence of exercise mediated hypoglycaemia in individuals with T1D in a free-living setting. Methods: Individuals with T1D were recruited into a prospective randomised controlled cross over study. Participants completed three 14-day periods in random order. In one period participants undertook moderate intensity exercise for a minimum of 30 minutes, at least 3 times a week (control period). In the other periods, participants incorporated 10s (every 20 mins) or 4s sprints (every 2 mins) into the exercise regimen. The primary outcome was the incidence of hypoglycaemia, defined as sensor glucose readings <3.5mmol/L for ≥ 20 minutes over the 14-day period. Secondary outcome measures included the incidence of hypoglycaemia <3.1mmol/L and percentage time <3.1mmol/L and <3.5mmol/L. Results: 24 participants completed the study. There was no difference in hypoglycaemic events (<3.5mmol/L) between the 4s and control period (p=0.28) or the 10s and control period (p=0.05). The 10s period was associated with fewer hypoglycaemia events <3.1mmol/L than the control period (p=0.04), with an 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 control, 4s and 10s periods respectively. The 10s period was associated with a reduction in time spent <3.5mmol/L (3.1% vs. 2.1%, p=0.03) and time spent <3.1mmol/L (1.9% vs 1.2%, p= 0.03). There was no increase in nocturnal hypoglycaemia during the sprinting periods. Conclusion: In a free-living setting, the inclusion of 10s sprints into moderate intensity exercise did not reduce hypoglycaemic events <3.5mmol/L but reduced hypoglycaemia <3.1mmol/l and the percentage time spent in hypoglycaemia. These observations may help active people with T1D to exercise more safely by reducing the risk of hypoglycaemia.