Background: Irisin, a recently identified myokine that seems had important role in hemostasis regulatation and improving insulin resistance. The effect of exercise training on serum irisin levels in type 2 diabates (T2D) is controversial. This study aims to investigate the effect of 6 weeks selective aerobic training on serum irisn levels and insulin resistance in women with T2D.

Materials and Methods: This research is a semi experimental study with pre-and post-test design. Research subjects were 20 women with T2D (mean age 47.4±5.6 years and BMI 29.92±3.42). Subjects were randomly divided into 2 groups: exercise group (n=12) and control group (n=8). Training protocol performed in 6 weeks (4 times a weeks, 40-65 min per session) and main training intencity and time were increased per week (50%-80% Hrmax). Main aerobic training was performed in 6 blocks, each block consisted of 32. Blood sample was collected before the and after end of training protocol.

Results: The results showed significant decrease in blood glucose, insulin and insulin resistance index and significant increase in serum irisin levels in exercise group compared with the control group (p≤0.05), but there is no significant correlation between serum irisin levels and insulin resistance.

Conclusion: It seems that aerobic training can have considerable impact on serum irisin levels, fasting blood glucos and insulin resistance index in women with T2D.

Background: Irisin is a new myokine that exerts its positive effects via increasing energy expenditure. The purpose of this study was to determine the effect of submaximal aerobic training on serum irisin level and irisin-related insulin-resistance change in obese men.

Materials and Methods: In this study, 26 obese men were selected as statistical sample and they were divided into experimental groups. Former group (13 men) consisted of subjects who carried out exercise training with 50-60 percent of maximum max heart rate for 10 continuous weeks (3 sessions per week for 30 to 45 minutes in each session). Later group was consisted of subjects who do not carried out exercise training. After  the interventions of study, irisin serum levels, insulin resistance indices, body composition and maximum oxygen consumption were determined.  Finally, data were analyzed by Stata software.

Results: Statistical data analysis illustrated that the amounts of irisin serum were significantly increased in exercise training group than control group (14.75±6.22; p=0.022) after the intervention. Also, only body fat percentage (1.242±0.57) and max oxygen consumption (1.509±0.328) of subjects were significantly increased (p=0.034 and p=0.0001, respectively). However, there were not statistically significant changes in irisin- related insulin-resistance indices (p>0.05).    

Conclusion: Current study presented that serum irisin was increased after 30 submaximal exercise training sessions regardless of insulin resistance changes in obese men.

Background: Irisin is an exercise-induced myokine that is reduced with type 2 diabetes and improves insulin resistance via the browning of white adipose tissues. However, irisin response to two types of exercise in patients with type 2 diabetes is unknown.

Materials and Methods: In this study, 22 diabetic Wistar rats (Induced by high-fat diet and injections Stz) were randomly assigned to 3 groups: high intensity interval exercise (HIIT), low intensity continuous training (LICT) and control (C). Both HIIT and LICT groups trained on the treadmill 5 sessions per week for 8 weeks. Blood samples were taken 24 hours after the last training session and plasma irisin, insulin and glucose levels were measured. ANOVA and Tukey post hoc tests were used to analyze data and the level of significance has been considered at p≤0.05.

Results: Data analysis showed that plasma irisin levels in the HIIT group were significantly increased compared to the control group (p<0.05). However, there was no significant difference between other groups (p>0.05). Plasma glucose in both HIIT and LICT groups was significantly decreased compared to the control group (p<0.05). But plasma insulin levels and insulin resistance index were not different between groups (p>0.05).

Conclusion: The results of this study showed that exercise training can increase plasma irisin in rats with type 2 diabetes. However, these changes are partially dependent on the type of exercise training.

Abstract

Background: Recently a myokine named irisin has been discovered that effects on obesity, metabolism and glucose homeostasis through browning white adipose tissue and thermogenesis. However, the effects of type and intensity of exercises on it have remained unclear. The purpose of this study was to evaluate the effects of two acute eccentric and concentric exercises on serum irisin level and insulin resistance in obese sedentary women.

Materials and Methods: The study was quasi-experimental. 15 female students with a body mass index above 30 kg/m² and mean age 24.86±2.87 years participated in the study. After measuring the maximal uptake oxygen of participants, they did two acute eccentric and concentric exercises using treadmill in a cross-over design within 10 days. After at least 8 hours- fasting, blood samples were collected before and immediately after each activity, to measure the levels of irisin, glucose and insulin. Data were analyzed using paired t-test and repeated measures ANOVA. In addition, Pearson correlation was used to examine the relationship between variables.

Results: the irisin levels increased significantly after both types of exercises (p<0.05), that this increase in concentric activity was more than eccentric activity. Insulin resistance increased immediately after both exercises as well, that this increase in concentric exercise was statistically significant (p<0.05).

Conclusion: However, both eccentric and concentric exercises had no effect on improving insulin resistance in obese women, but they can be considered as a good stimulus for the secretion of Irisin.