Plasma Apelin Unchanged With Acute Exercise Insulin Sensitization

Area of Science:

• Exercise Physiology
• Metabolic Regulation
• Endocrinology

Background:

• Mechanisms of post-exercise insulin sensitization are not fully understood.
• Apelin is known to enhance glucose uptake and insulin sensitivity.
• The role of apelin in exercise-induced insulin sensitivity is unexplored.

Purpose of the Study:

• Investigate apelin's response to maximal and submaximal aerobic exercise.
• Elucidate apelin's influence on insulin sensitivity following acute exercise.

Main Methods:

• Twelve healthy adults (7 male, 5 female) underwent maximal (VO2max) and submaximal (70-75% VO2max) treadmill exercise and a glucose challenge.
• Blood samples were collected pre-exercise, post-exercise, 1hr post, and 24hrs post for glucose, insulin, and apelin analysis.
• Hepatic insulin sensitivity was assessed using HOMA-IR and QUICKI indices.

Main Results:

• Plasma apelin levels did not significantly change with exercise condition or time.
• Blood glucose and insulin increased immediately after maximal exercise and glucose challenge, but remained stable after submaximal exercise.
• Insulin sensitivity significantly improved 1hr post-submaximal exercise (HOMA-IR, QUICKI).
• Resting plasma apelin correlated with insulin, HOMA-IR, and QUICKI.

Conclusions:

• Submaximal aerobic exercise enhances hepatic insulin sensitivity 1 hour post-exercise.
• This exercise-induced insulin sensitization occurs independently of changes in plasma apelin levels.