Pancreatic β-cell function is a stronger predictor of changes in glycemic control after an aerobic exercise intervention than insulin sensitivity

J Clin Endocrinol Metab. 2013 Oct;98(10):4176-86. doi: 10.1210/jc.2013-2232. Epub 2013 Aug 21.

Abstract

Context: Understanding intersubject variability in glycemic control following exercise training will help individualize treatment.

Objective: Our aim was to determine whether this variability is related to training-induced changes in insulin sensitivity or pancreatic β-cell function.

Design, setting, and participants: We conducted an observational clinical study of 105 subjects with impaired glucose tolerance or type 2 diabetes.

Interventions and main outcome measures: Individual subject changes in fitness (VO2max), glycemia (glycosylated hemoglobin, fasting glucose, oral glucose tolerance test), insulin sensitivity (hyperinsulinemic-euglycemic clamp), oral glucose-stimulated insulin secretion (GSIS), and disposition index (DI) were measured following 12 to 16 weeks of aerobic exercise training. Regression analyses were used to identify relationships between variables.

Results: After training, 86% of subjects increased VO2max and lost weight. Glycosylated hemoglobin, fasting glucose, and 2-hour oral glucose tolerance test were reduced in 69%, 62%, and 68% of subjects, respectively, while insulin sensitivity improved in 90% of the participants. Changes in glycemic control were congruent with changes in GSIS such that 66% of subjects had a reduction in first-phase GSIS, and 46% had reduced second-phase GSIS. Training increased first- and second-phase DI in 83% and 74% of subjects. Training-induced changes in glycemic control were related to changes in GSIS (P < .05), but not insulin sensitivity or DI, and training-induced improvements in glycemic control were largest in subjects with greater pretraining GSIS.

Conclusions: Intersubject variability in restoring glycemic control following exercise is explained primarily by changes in insulin secretion. Thus, baseline and training-induced changes in β-cell function may be a key determinant of training-induced improvements in glycemic control.

Trial registration: ClinicalTrials.gov NCT01234155.

Publication types

  • Clinical Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism*
  • Body Mass Index
  • Diabetes Mellitus, Type 2 / physiopathology
  • Diabetes Mellitus, Type 2 / therapy*
  • Exercise / physiology*
  • Exercise Therapy*
  • Female
  • Glucose Intolerance / physiopathology
  • Glucose Intolerance / therapy*
  • Glucose Tolerance Test
  • Humans
  • Insulin Resistance / physiology*
  • Insulin-Secreting Cells / physiology*
  • Male
  • Obesity / physiopathology
  • Obesity / therapy
  • Treatment Outcome
  • Weight Loss / physiology

Substances

  • Blood Glucose

Associated data

  • ClinicalTrials.gov/NCT01234155