In the Journals

Exercise intervention improves left ventricular function in type 1 diabetes

Aerobic capacity and left ventricular function significantly improved after 20 weeks of regular intense exercise in adolescents with and without type 1 diabetes, according to findings published in Diabetes Care.

Silmara Gusso, PhD, MSc, of Liggins Institute at the University of Auckland in New Zealand, and colleagues evaluated 53 adolescents (mean age, 15.6 years) with type 1 diabetes assigned to a 20-week exercise training intervention (n = 38) or no training (n = 15), as well as healthy adolescents (mean age, 16.7 years) without type 1 diabetes also assigned to the exercise training intervention, to determine the impact of exercise on aerobic capacity (VO2peak) of left ventricular function and glycemic control. The exercise training intervention consisted of four 60-minute exercise sessions per week.

Percentage of body fat decreased and fat-free mass increased in both exercise groups. Daily insulin consumption decreased by approximately 10% in the training group with type 1 diabetes.

During the exercise sessions, all participants achieved up to 85% of their VO2peak heart rate.

At baseline, VO2peak expressed by liters per minute adjusted for age, sex and fat-free mass was lower in participants with diabetes.

Resting and maximal exercise systolic, diastolic and mean arterial pressure were not altered by exercise training. Both groups with type 1 diabetes had higher resting heart rate at baseline compared with participants without diabetes.

After 20 weeks, resting heart rate decreased in both training groups. The training group with diabetes had decreased mean arterial pressure, submaximal exercise systolic blood pressure and resting diastolic BP after the 20-week intervention.

Left ventricular function at rest significantly improved, stroke volume increased and heart rate in the supine position decreased in both exercise training groups. No change in end-systolic volume was observed in the training group with diabetes, whereas it increased in participants with diabetes who did not train. The training diabetes group experienced an increase in resting ejection fraction, whereas participants with diabetes who did not train experienced a decrease.

Both training groups experienced significant increases in submaximal exercise cardiac output, stroke volume, end-diastolic volume and ejection fraction compared with participants who did not exercise.

Significant improvements in contractility and a significant decrease in end-systolic volume after the intervention were observed in the training group with diabetes, whereas these changes were not observed in the training group without diabetes.

No changes in total peripheral resistance at rest were observed after the 20-week intervention, but total peripheral resistance during submaximal exercise significantly reduced in the training group with diabetes compared with the training group without diabetes.

Higher resting heart rate, higher resting diastolic BP and higher resting mean arterial pressure were associated with higher HbA1c levels. VO2peak in both groups with diabetes was inversely associated with glycemic control.

“In trained adolescents with type 1 diabetes, increased stroke volume was achieved by both increased and end-diastolic volume and reduced end-systolic volume, consistent with improved filling and increased left ventricular contractility after training,” the researchers wrote. “Given the potential to prevent or reverse the progressive diastolic abnormalities that occur in diabetes, our data support regular intense exercise in adolescents with diabetes.” – by Amber Cox

Disclosures: The authors report no relevant financial disclosures.

Aerobic capacity and left ventricular function significantly improved after 20 weeks of regular intense exercise in adolescents with and without type 1 diabetes, according to findings published in Diabetes Care.

Silmara Gusso, PhD, MSc, of Liggins Institute at the University of Auckland in New Zealand, and colleagues evaluated 53 adolescents (mean age, 15.6 years) with type 1 diabetes assigned to a 20-week exercise training intervention (n = 38) or no training (n = 15), as well as healthy adolescents (mean age, 16.7 years) without type 1 diabetes also assigned to the exercise training intervention, to determine the impact of exercise on aerobic capacity (VO2peak) of left ventricular function and glycemic control. The exercise training intervention consisted of four 60-minute exercise sessions per week.

Percentage of body fat decreased and fat-free mass increased in both exercise groups. Daily insulin consumption decreased by approximately 10% in the training group with type 1 diabetes.

During the exercise sessions, all participants achieved up to 85% of their VO2peak heart rate.

At baseline, VO2peak expressed by liters per minute adjusted for age, sex and fat-free mass was lower in participants with diabetes.

Resting and maximal exercise systolic, diastolic and mean arterial pressure were not altered by exercise training. Both groups with type 1 diabetes had higher resting heart rate at baseline compared with participants without diabetes.

After 20 weeks, resting heart rate decreased in both training groups. The training group with diabetes had decreased mean arterial pressure, submaximal exercise systolic blood pressure and resting diastolic BP after the 20-week intervention.

Left ventricular function at rest significantly improved, stroke volume increased and heart rate in the supine position decreased in both exercise training groups. No change in end-systolic volume was observed in the training group with diabetes, whereas it increased in participants with diabetes who did not train. The training diabetes group experienced an increase in resting ejection fraction, whereas participants with diabetes who did not train experienced a decrease.

Both training groups experienced significant increases in submaximal exercise cardiac output, stroke volume, end-diastolic volume and ejection fraction compared with participants who did not exercise.

Significant improvements in contractility and a significant decrease in end-systolic volume after the intervention were observed in the training group with diabetes, whereas these changes were not observed in the training group without diabetes.

No changes in total peripheral resistance at rest were observed after the 20-week intervention, but total peripheral resistance during submaximal exercise significantly reduced in the training group with diabetes compared with the training group without diabetes.

Higher resting heart rate, higher resting diastolic BP and higher resting mean arterial pressure were associated with higher HbA1c levels. VO2peak in both groups with diabetes was inversely associated with glycemic control.

“In trained adolescents with type 1 diabetes, increased stroke volume was achieved by both increased and end-diastolic volume and reduced end-systolic volume, consistent with improved filling and increased left ventricular contractility after training,” the researchers wrote. “Given the potential to prevent or reverse the progressive diastolic abnormalities that occur in diabetes, our data support regular intense exercise in adolescents with diabetes.” – by Amber Cox

Disclosures: The authors report no relevant financial disclosures.