Delayed hypoglycaemia in people with type 1 diabetes after performing moderate intensity exercise before the evening meal

Time spent in hypoglycemia is comparable when the same amount of exercise is performed 5 or 2 days weekly: a randomized crossover study in people with type 1 diabetes

INTRODUCTION

People with type 1 diabetes are recommended to exercise regularly. However, limited evidence exists on how frequency and duration of exercise affect the risk of hypoglycemia. The study aimed to compare the percentage of time spent in hypoglycemia between two 5-day periods with different frequency and duration of physical activity.

RESEARCH DESIGN AND METHODS

In this outpatient randomized crossover study, 26 participants aged 18-65 years with type 1 diabetes for ≥2 years and insulin pump use for ≥1 year were included. After a 7-day observation period, participants completed two 5-day intervention periods separated by a washout period of at least 14 days. One period included five exercise sessions on 5 consecutive days (5S), each consisting of 4 min of resistance training and 30 min of aerobic exercise. Another period included two exercise sessions on 2 days with at least 2 days in between (2S), each consisting of 10 min of resistance training and 75 min of aerobic exercise. During each period, participants performed in total 150 min of aerobic exercise and 20 min of resistance training and wore continuous glucose monitors (Dexcom G6) and accelerometers (ActiGraph wGT3X-BT).

RESULTS

Twenty insulin pump-treated adults (10 women) with type 1 diabetes completed the study. The baseline median (range) age was 48 (24-64) years, glycated hemoglobin 55 (44-66) mmol/mol, diabetes duration 24 (8-57) years, and body mass index 28.4 (22.3-35.8) kg/m². No differences were observed between 5S and 2S in the percentage (mean±SD) of time spent below 3.9 mmol/L (3.5%±2.8% vs 4.5%±4.2%, p=0.28), time spent in 3.9-10.0 mmol/L (65.3%±15.0% vs 68.5%±13.6%, p=0.31), time spent above 10.0 mmol/L (31.2%±16.4% vs 27.3%±14.5%, p=0.15), mean glucose (8.7±1.3 mmol/L vs 8.5±1.2 mmol/L, p=0.33) and glycemic variability (35.8%±5.3% vs 35.8%±6.6%, p=0.97).

CONCLUSIONS

Time spent in hypoglycemia was comparable between the two 5-day periods with different duration and frequency of physical activity.

TRIAL REGISTRATION NUMBER

NCT04089462.

The Effects of Basal Insulin Suspension at the Start of Exercise on Blood Glucose Levels During Continuous Versus Circuit-Based Exercise in Individuals with Type 1 Diabetes on Continuous Subcutaneous Insulin Infusion

BACKGROUND

Exercise causes glycemic disturbances in individuals with type 1 diabetes (T1D). Continuous moderate-intensity aerobic exercise (CON) generally lowers blood glucose (BG) levels and often leads to hypoglycemia. In comparison, circuit-based exercise (CIRC) may attenuate the drop in BG. The goal of this study is to contrast the effects of basal insulin suspension at the onset of two different forms of exercise (CON vs. CIRC).

METHODS

Twelve individuals (six men and six women) with T1D on insulin pump therapy were recruited for the study. All participants completed a maximal aerobic fitness test and two 40-min exercise sessions, consisting of either continuous treadmill walking or a circuit workout. Basal insulin infusion was stopped at the onset of exercise and resumed in recovery. After providing an initial reference value, volunteers were blinded to their [BG] and were asked to estimate their levels during exercise.

RESULTS

Oxygen consumption (47.5 ± 7.5 vs. 54.5 ± 13.5 mL·kg^-1·min^-1, P = 0.03) and heart rate (122 ± 20 vs. 144 ± 20 bpm, P = 0.003) were lower in CON vs. CIRC. Despite the lower workload, BG levels dropped more with CON vs. CIRC (delta BG = -3.8 ± 1.5 vs. -0.5 ± 3.0 mmol/L for CON vs. CIRC, respectively, P = 0.001). Participants were able to estimate their BG more accurately during CON (r = 0.83) vs. CIRC (r = 0.33) based on a regression analysis.

CONCLUSION

Despite a lower intensity of exercise, with full basal insulin suspension at the start of exercise, CON results in a larger drop in BG vs. CIRC. These findings have implications for single hormone-based artificial pancreas development for exercise. While this study does not negate the importance of frequent capillary BG monitoring during exercise, it does suggest that if persons are knowledgeable about their pre-exercise BG levels, they can accurately perceive the changes in BG during CON, but not during CIRC.