This real-world, at-home study sought to determine the glycaemic effects of three different types of exercise programme (aerobic, interval or resistance) in adults with type 1 diabetes. A total of 497 volunteers were randomly assigned to repeat one of three 30-minute, video-guided exercise sessions, with no restrictions on time of day or session frequency. Participants also reported other physical activities and food intake via an app developed for the study.
Overall, 89% of the participants completed the target of six exercise sessions over the 4-week study period, with a median interval of 4 days between study exercise sessions. Participants were physically active for a median of 4.3 hours per week (with an average daily step count of 7991), of which 0.7 hours comprised the study exercise.
During the 30-minute exercise sessions, blood glucose fell by 1.0, 0.8 and 0.5 mmol/L in the aerobic, interval and resistance groups, respectively. Despite differences in acute glycaemia between the exercise types, there was a consistent increase in time in range (TIR) across all three groups on exercise days versus non-exercise days (mean, 76% vs 70%). However, there were marked individual differences, with 40% of participants seeing a >5% increase in TIR on exercise days and, conversely, 18% of participants seeing a >5% reduction. Time below range was low overall, but was significantly higher on exercise days than non-exercise days (1.1% vs 0.4%).
The authors contrast their findings with previous laboratory-based studies, in which interval and resistance exercise led to a rise in blood glucose, rather than the fall observed here. They attribute the differences to a lower intensity of effort (as measured by heart rate) in the present study, and to the fact that exercise was not restricted to the morning in a fasted state.
The authors conclude that their findings reinforce the value of exercise in people with type 1 diabetes, as days with structured exercise sessions contributed to clinically meaningful improvements in glucose TIR.
Vinod Patel highlights the growing evidence base that lifestyle interventions are effective, and encourages persistence even though they can be difficult.
25 May 2023