Due to significant glycemic excursions, exercising with T1D can be challenging. Closed loop (CL) has been shown to improve glycemia in people with T1D.
The aim was to evaluate CL performance compared with standard therapy in people with T1D undertaking exercise.
Ten adults with T1D were randomly recruited from a large randomised controlled trial investigating CL versus standard therapy. Four participants were randomised to the standard therapy and 6 were randomised to CL. Participants undertook high-intensity-interval-exercise (HIIE) and moderate-intensity-exercise (MIE), 45-minutes duration, in random-order. Frequent venous samples measured glucose, ketones, lactate, free insulin, and counter-regulatory hormones. The primary outcome was CGM time-in-target range from beginning of exercise to 24 hours post exercise.
Compared with standard therapy, CL resulted in improved time-in-range (66.5% vs 42%) and reduced time in hypoglycemia (11.3% vs 8.6%) for aerobic exercise and improved mean sensor glucose (9.8mmol/L vs 8.2mmol/L, p=0.0237) with no increase in hypoglycemia for anaerobic exercise.
Standard Therapy (n=5) | Hybrid Closed Loop (n=4) | p value | |
Aerobic Exercise | |||
%time in 70-180mg/dL | 42.3(16.7) | 66.5(11.2) | 0.0349* |
Mean sensor glucose(mg/dL) | 9.5(1.9) | 8.6(0.7) | 0.3474 |
Time<70mg/dL(%)1 | 11.3(14.1) | 0(3.7) | 0.0463* |
Time<50mg/dL(%) | 2.1(11.4) | 0(0) | 0.2444 |
Time>180mg/dL(%) | 43.5(24.1) | 31.9(10.6) | 0.3631 |
Time>250mg/dL(%) | 17.9(12.1) | 6.7(5.1) | 0.1017 |
Anaerobic Exercise | |||
%time in 70-180mg/dL | 61.2(29.9) | 75.3(16.5) | 0.0550 |
Mean sensor glucose(mg/dL) | 9.8(1.5) | 7.5(1.1) | 0.0237* |
Time<70mg/dL(%) | 2.6(3.4) | 5.1(4.9) | 0.4064 |
Time<50mg/dL(%) | 0(0) | 0(2.0) | 0.2235 |
Time>180mg/dL(%) | 37.2(31.9) | 14.8(8.2) | 0.0550 |
Time>250mg/dL(%) | 11.3(13.3) | 0(2.0) | 0.1724 |
Glucose metrics from beginning of exercise to 24hrs post exercise
Closed loop results in improved glycaemia compared with standard therapy during and after exercise without increase in hypoglycemia.