The time lag prior to the rise in glucose requirements to maintain stable glycaemia during moderate exercise in a fasted insulinaemic state is of short duration and unaffected by the level at which glycaemia is maintained in Type 1 diabetes

• Published in: Diabetic medicine 2018-10, Vol.35 (10), p.1404-1411
• Main Authors: Shetty, V. B., Fournier, P. A., Davey, R. J., Retterath, A. J., Paramalingam, N., Roby, H. C., Davis, E. A., Jones, T. W.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Blood glucose; Blood Glucose - drug effects; Blood Glucose - metabolism; Diabetes; Diabetes mellitus; Diabetes mellitus (insulin dependent); Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - complications; Diabetes Mellitus, Type 1 - drug therapy; Drug Administration Schedule; Epinephrine; Exercise; Exercise - physiology; Fasting - blood; Female; Glucose; Glucose - administration & dosage; Humans; Hyperinsulinism - blood; Hyperinsulinism - chemically induced; Hyperinsulinism - drug therapy; Hypoglycemia; Hypoglycemia - chemically induced; Hypoglycemia - drug therapy; Insulin; Insulin - administration & dosage; Insulin - adverse effects; Male; Oxygen consumption; Time Factors; Young Adult
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.13771

Aims To determine the duration of the low hypoglycaemia risk period after the start of moderate‐intensity exercise performed under basal insulinaemic conditions and whether this period is affected by the level at which glycaemia is maintained under these conditions. Methods This was a prospective, randomized counterbalanced study. Eight participants with Type 1 diabetes (mean ± sd age 21.5 ± 4.0 years) underwent either a euglycaemic (5–6 mmol/l) or hyperglycaemic clamp (9–10 mmol/l) on separate days and were infused with insulin at basal rates and [6,6‐2H]glucose while cycling for 40 min at 50% maximum oxygen consumption rate. The main outcome measures were the glucose infusion rates required to maintain stable glycaemia and glucoregulatory hormone levels, and rates of glucose appearance and disappearance. Results During the first 20 min of exercise, the glucose infusion rate did not increase significantly, irrespective of the level at which glycaemia was maintained, but increased acutely between 20 and 25 min under both conditions. Maintaining higher glycaemia resulted in higher glucose infusion rate during, but not early post‐exercise. With the exception of epinephrine, the glucoregulatory hormone levels and rates of glucose appearance and disappearance were similar between conditions. Conclusion Irrespective of the levels at which glycaemia is maintained, there is a 20‐min low exogenous glucose demand period during which the exogenous glucose requirements to maintain stable glycaemia do not increase during moderate exercise performed at basal insulin level. What's new? During the first 20 min of moderate‐intensity exercise performed under basal insulinaemic conditions, there is no increase in exogenous carbohydrate (CHO) requirements to maintain stable glycaemia, irrespective of the levels at which glycaemia is maintained in individuals with Type 1 diabetes. Irrespective of the level at which glycaemia is maintained, there is an acute rise in the CHO requirement to maintain stable glycaemia 20 min after the start of moderate‐intensity exercise. Maintaining mild hyperglycaemia compared with euglycaemia increases the amount of CHO required to maintain stable glycaemia before and during exercise, but not during the post‐exercise period.