Effects of Exercise on Incretin Hormones

• Author / Creator

  Toghi Eshghi, Saeed Reza

• The prevalence of type 2 diabetes (T2D) has been dramatically increasing globally. Exercise is recommended as a first line treatment, along with diet and medications. The mechanisms by which exercise improves glycemic control are not fully understood but are typically attributed to changes in insulin sensitivity, particularly at the level of skeletal muscle. Furthermore, the effects of exercise on other hormones that are involved in the pathogenesis of diabetes, such as incretins, also known as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), are much less well understood. Early research has shown that exercise can increase incretins in healthy subjects.
  To our knowledge, no studies in patients with T2D have been published at the time this dissertation began. Therefore, a series of studies were conducted to: 1- to systematically review the effect of acute exercise on endogenous incretin hormone concentrations in different populations; 2- to examine the effects of a single bout of moderate exercise, 28 days of metformin and their combination on plasma concentrations of total GLP-1 and GIP before and after meal ingestion; and 3- to examine the effect of two bouts of long duration, moderate intensity aerobic exercise on active and total GLP-1 and GIP.
  Results showed that a single bout of aerobic exercise can significantly increase plasma concentrations of GLP-1 only in normal weight healthy participants but not in individuals with obesity. While adding an acute bout of exercise (i.e., 35 minutes) to 28 days of metformin treatment in people with T2D did not have any effects on incretins, metformin significantly increased total GLP-1 and GIP concentrations. On the other hand, long-duration (i.e., two bouts of 1.5 hours), moderate-intensity aerobic exercise increased next day fasting incretins both in healthy and T2D participants.
  In conclusion, there is some evidence to support the role of exercise in increasing GLP-1 concentrations in healthy individuals. On the other hand, the effect of acute exercise on GIP is less consistent. The available literature on the effects of exercise in obesity and T2D is very limited. The two original studies in the current thesis suggest that long duration exercise might be necessary to cause small effect on incretins in T2D.

• Subjects / Keywords

  • Exercise
  • Glucose-dependent insulinotropic peptide
  • Glucagon-like peptide-1
  • Incretin

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R30G3HD88

• License

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