Journal Article

Plasma Irisin Modestly Increases during Moderate and High-Intensity Afternoon Exercise in Obese Females

Grunewald, Zachary I., Nyhoff, Lauren M., Kanaley, Jill A., Liu, Ying, Winn, Nathan C., Heden, Timothy D.

2017

Overview

Irisin is an exercise-responsive myokine that has been proposed to exert anti-obesity benefits; yet its response during exercise in obese women is not described. This study characterized plasma irisin levels during a single bout of afternoon isocaloric-exercise of different intensities (moderate- vs high-intensity) in obese females. Eleven obese females participated in 3 randomized study days beginning at 1600h: 1) no exercise (NoEx), 2) moderate exercise (ModEx; 55%VO2max) and 3) high intensity interval exercise (IntEx; 4 min (80%VO2max)/3 min (50% VO2max). Frequent blood samples were analyzed for glucose and lactate (whole-blood), and insulin, c-peptide, glucagon, and irisin (plasma) throughout 190 min of testing. Plasma irisin increased above baseline during ModEx and IntEx (P<0.05), but not NoEx (P>0.05). Peak irisin levels during ModEx and IntEx exercise were 11.9± 3.4% and 12.3 ± 4.1% relative to baseline (P<0.05), respectively, with no differences between exercise intensities (P>0.05). Irisin levels remained elevated above resting for 125 minutes post-exercise during ModEx, whereas levels returned to baseline within 15 minutes post-exercise during IntEx. Similarly, no associations were found between plasma irisin levels and circulating lactate, glucose, insulin, c-peptide, or glucagon among study days (P>0.05). However, there was an inverse association between basal irisin and lean mass (r = -0.70, P = 0.01). A single bout of moderate and high intensity afternoon exercise induces modest increases in circulating irisin concentrations during exercise; however the regulation post-exercise appears to be dimorphic between exercise intensity in obese females. Future studies are needed to compare morning and afternoon exercise on irisin secretion.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adult / Aerobics / Biology and Life Sciences / Blood / Blood Glucose / Body Mass Index / C-Peptide - blood / Chemokines / Complications and side effects / Diabetes / Exercise / Exercise physiology / Female / Females / Fibronectins - blood / Fibronectins - genetics / Fitness training programs / Gene Expression / Genetic aspects / Glucagon / Glucagon - blood / Glucose / Homeostasis / Hormones / Humans / Insulin / Kinases / Lactic Acid / Medicine and Health Sciences / Metabolic syndrome / Musculoskeletal system / Nutrition research / Obesity / Obesity - blood / Oxygen consumption / Oxygen Consumption - physiology / Physical fitness / Physiological aspects / Plasma / Random Allocation / Rodents / Secretion / Sports training / Strength training / Time Factors / Weight control