Exploring the variability in acute glycemic responses to exercise in type 2 diabetes

Abstract

Aim: To explore the factors associated with exercise-induced acute capillary glucose (CapBG) changes in individuals with type 2 diabetes (T2D).

Methods: Fifteen individuals with T2D were randomly assigned to energy-matched high intensity interval exercise (HI-IE) and moderate intensity continuous exercise (MI-CE) interventions and performed a designated exercise protocol 5 days per week for 12 weeks. The duration of exercise progressed from 30 to 60 minutes. CapBG was measured immediately before and after each exercise session. Timing of food and antihyperglycemic medication intake prior to exercise was recorded.

Results: Overall, the mean CapBG was lowered by 1.9 mmol/L (P < 0.001) with the change ranging from -8.9 to +2.7 mmol/L. Preexercise CapBG (44%; P < 0.001), medication (5%; P < 0.001), food intake (4%; P = 0.043), exercise duration (5%; P < 0.001), and exercise intensity (1%; P = 0.007) were all associated with CapBG changes, explaining 59% of the variability.

Conclusion: The greater reduction in CapBG seen in individuals with higher preexercise CapBG may suggest the importance of exercise in the population with elevated glycemia. Lower blood glucose can be achieved with moderate intensity exercise, but prolonging exercise duration and/or including brief bouts of intense exercise accentuate the reduction, which can further be magnified by performing exercise after meals and antihyperglycemic medication. This trial is registered with ClinicalTrial.gov NCT01144078.

Figures

Figure 1

Effects of exercise intervention, exercise duration, exercise modality, food intake, and medication on exercise-induced CapBG reduction. Values are least square mean ± SE. *HI-IE (P = 0.007), †45 min exercise (P = 0.015), ‡60 min exercise (P < 0.001), §food intake <2 hours (P = 0.043), and ψmedication ≤6 hours of exercise (P < 0.001) were all associated with greater CapBG reduction. HI-IE: high intensity interval exercise; MI-CE: moderate intensity continuous exercise; CapBG: capillary blood glucose.

Figure 2

Correlations between preexercise CapBG and exercise-induced CapBG changes for both HI-IE and MI-CE. Filled and open squares represent MI-CE and HI-IE, respectively. Dotted and straight lines are regression lines of MI-CE and HI-IE, respectively. Glucose data obtained from each participant are categorized based on exercise intensity, duration, and modality, as well as food and medication status. Each box in the figure represents the mean glucose value obtained from each participant under different conditions. HI-IE: high intensity interval exercise; MI-CE: moderate intensity continuous exercise; CapBG: capillary blood glucose.