[ effect of high intensity interval training on the serum levels of irisin and fibroblastic growth factor-21 [FGF-21], and insulin resistance in obese male rats]

Introduction: the purpose of this study was to investigate the effects of high intensity interval training [HIIT] and moderate intensity continuous training [MICT] on irisin, FGF-21 and insulin resistance in obese male rats

Material and Methods: forty male rats were divided into two groups: high-fat diet [n=32] and standard diet [n=8], for 10 weeks. After inducing obesity, eight rats from the high-fat diet group [O] and eight from the standard dietary group [C] were sacrificed, and the other obese rats were randomly divided into three groups: obesity control [OC], moderate intensity continuous training [MICT] and high intensity interval training [HIIT]. The HIIT protocol, including 10 bouts of 4-minute activity with equivalent intensity of 85-90% vo2max and 2 minute active rest periods, and the MICT protocol with equivalent intensity of 65-70% VO2max, with covered distance matched to that of the HIIT protocol, were performed for 12 weeks and 5 sessions per week. Serum samples were collected in two steps [after completion of diet and training protocols] to measure serum levels of irisin, FGF-21, insulin and glucose by ELISA

Results: in the comparison of the HIIT group to the OC group, serum levels of irisin [6.43 +/- 0.93 ng/ml vs. 4.61 +/- 0.61 ng/ml, p=0.003] and FGF-21 [1658 +/- 206.5 ng/l vs. 1093 +/- 125.97 ng/l, P=0.007] significantly increased, while MICT had no significant effect on these two hormones [P=0.29, P=1.00 respectively]. Also, when comparing both the HIIT and MICT groups to the OC group, serum levels of glucose [HIIT: 111.16 +/- 4.07 mg/dl, MICT: 117.5 +/- 1.37 mg/dl vs. 154.66 +/- 13.21 mg/dl, P=0.001, P=0.001 respectively] and insulin resistance index [HIIT: 1.96 +/- 0.20, MICT: 2.53 +/- 0.46 vs. 3.89 +/- 0.54, P=0.001, P=0.01 respectively] significantly decreased; although, serum insulin reduction [1.49 +/- 0.15 ng/ml vs. 2.14 +/- 0.43 ng/ml, P=0.018] was only significant in the HIIT group [P=0.018]

Conclusion: it seems that both HIIT and MICT training protocols lead to improved insulin resistance in obese rats. However the increase in serum irisin and FGF-21 was significant only in the HIIT group, suggesting that exercise intensity plays an important role in regulating the secretion of these hormones

[Interaction of long term calorie restriction and aerobic training programs on serum and tissue concentrations of adiponectin in male obese rats]

Introduction: the aim of present study was to investigate the interaction of aerobic training and calorie restriction on levels of adiponectin isomers in serum and abdominal fat depots in obese male rats

Materials and Methods: forty-eight wistar male rats were used as the study sample. Blood and tissue samples were collected at the 1[st], 18[th] and 28[th] weeks. After baseline sampling, the remaining 40 rats were randomly divided into control and high-fat-diet groups. The high-fat-diet group received their regimen for 18 weeks and were then randomly divided into the negative energy balance [NEB] and high-fat-diet [HFD] subgroups. NEB group alternately underwent 25% calorie restriction or aerobic training [running] with an intensity of 70 to 75% of vo2max for 10 weeks

Results: compared to the standard diet, HFD feeding increased weight and decreased retroperitoneal adipose tissue adiponectin level at the 18[th] and 28[th] weeks [P<0.05]. In comparison to the HFD, group negative energy balance in obese male rats, caused weight control with significant increase in serum levels of total and high-molecular-weight adiponectin as well as adiponectin levels in retroperitoneal and mesenteric fat depots [P<0.05]. Also insulin resistance index in line with serum concentrations of insulin, glucose and triglycerides were decreased in negative energy balance, compared to the high-fat-diet group [P<0.05]

Conclusion: this study indicates that even with simultaneous consumption of high-fat-diet, combination of aerobic training and calorie restriction can increase concentrations of adiponectin in serum and abdominal fat depots of obese male rats, and aligned with it improves lipid and metabolic profiles

[ effect of obesity and endurance training-induced weight loss on UCP3 mRNA expression in C57BL/6 MICE]

The purpose of this study was evaluating the effect of obesity and weight reduction induced by endurance training on UCP3 mRNA expression in C57BL/6 mice. Twenty-four C57BL/6 mice consumed a high-fat diet, while 6 [NB Group] were fed a normal chow for 12 weeks. After the fattening period, 6 obese mice [OB Group] were sacrificed. Twelve mice trained 5 sessions per week for 12 weeks on a rodent treadmill with high [HI Group] [75% VO2max] and/or low intensity [LI Group] [50% VO2max] during a training period. The control group [OC Group] was kept inactive in the cages till the end of the period. Body weight was measured and recorded weekly. UCP3 mRNA expression was measured in gastrocnemius muscle using Real Time-PCR method and plasma FFA concentrations were measured using the ELISA method. In the training groups, weight reduction was significant in the 8th week [p<0.05]. Average relative UCP3 mRNA expression was significantly lower in the HI and LI groups, than in the OC group [0.5 +/- 0.25 and 1.04 +/- 0.96, respectively, vs. 2.58 +/- 0.57 arbitrary unit; p<0.05]. Plasma FFA concentrations were significantly lower in the HI and OB groups compared to the LI group [p<0.05]. When energy intake and consequently body weight increases, UCP3 increases to extend the thermogenesis and fatty acid oxidation's process. In contrast, UCP3 downregulates with exercise-induced weight loss in order to counteract this process

Effect of 12 weeks life-style activity modification on serum oxidized LDL-C in obese men

Exercise significantly prevents the progression of atherosclerosis and oxidized LDL-C [ox-LDL-C], facilitates monocyte-related atherogenesis. The effects of Lifestyle Activity Modification [LAM] training based on guidelines of the Centers for Disease Control [CDC] and the American College of Sports Medicine [ACSM] on serum oxidized LDL-C [ox-LDL-C] in obese people are not well known. We investigated the effect of LAM on serum ox-LDL-C in obese middle aged men. Sixteen healthy obese middle aged men [aged 42.06 +/- 6.01 years, mean +/- SD] were randomly assigned to the LAM [n=8] and the control [n=8] groups. Subjects in the LAM group walked 2 miles daily in 30 minutes 4 days weekly for 12 weeks on treadmills, according to the CDC and ACSM guidelines. Results showed that body weight, BMI, body fat mass, body fat percent, waist to hip ratio [WHR] and LDL-C decreased significantly after 12 weeks in the LAM group compared to the controls [P<0.05], and their maximum oxygen uptake was increased significantly compared to the controls after 12 weeks [P<0.05]. On the other hand, after 12 weeks of LAM training, no significant differences were observed in serum ox-LDL-C, total cholesterol [TC], triglycerides [TG] and HDL-C between the groups. Although twelve weeks of LAM improved body composition and cardio-respiratory fitness and decreased LDL-C levels in obese middle aged men, serum ox-LDL-C were not affected by this protocol in this group

Effect of 12 weeks life-style activity modification [LAM] on adiponectin gene expression and plasma adiponectin in obese men

Central obesity down regulates adiponectin gene expression and plasma adiponectin concentration. The effects of lifestyle activity modification [LAM] training according to Centers for Disease Control [CDC] and American College of Sports Medicine ACSM guidelines on adiponectin gene expression and its secretion in obese people is not well known. The purpose of this study hence was to examine the effects of LAM on adiponectin gene expression and plasma adiponectin in obese men. Sixteen healthy middle aged men [42.06 +/- 6.01 years; mean +/- SD] participated in this study. The subjects were randomly assigned to the LAM [n=8] and control group [n=8]. Subjects in the LAM group walked 2 miles for 30 minutes for 4 days for 12 weeks on treadmill according to the CDC and ACSM guidelines. After 12 weeks LAM training, subjects were asked to avoid any high intensity physical activity for a week. The results showed that weight, BMI, body fat mass, body fat percent, central [visceral and subcutaneous] and peripheral subcutaneous fat volume, waist and hip circumstance and waist to hip ratio [WHR] were decreased significantly after 12 weeks in the LAM group, compared to the controls [P<0.05]. After one week detraining, body composition in the training group was maintained and did not change significantly. Also, maximum oxygen uptake, adiponectin gene expression on abdominal and hip subcutaneous adipose tissue were increased significantly in the LAM group compared to controls after 12 weeks [P<0.05]. On the other hand, after 12 weeks LAM training no significant differences were observed in plasma adiponectin and serum high sensitive C reactive protein [hs-CRP], levels between groups, while after one week detraining plasma adiponectin and serum hs-CRP levels were significantly increased and decreased respectively [P<0.05]. Although, twelve weeks LAM training improved body composition, cardiorespiratory fitness and adiponectine gene expression in obese men, but the intensity and time of these exercises are not enough to increase plasma adiponectin and hs-CRP reduction

[Effects of exercise training on high molecular weight adiponectin in healthy male rat]

The high-molecular weight [HMW] from of adiponectin is reported to be the most active from of this hormone and current data reveals decreased plasma HMW adiponectin levels to be associated with insulin resistance. This study was intended to investigate the effect of exercise intensity on plasma HMW adiponectin concentrations. Thirty-two eight week-old male Wistar rats [185 +/- 50 g] were randomly assigned to one of four groups as follows: High intensity [HI: 34 m/min %80 -%85 VO2 max] moderate intensity [MI: 23m/min%70-%75 VO2 max], Low intensity [LI: 20m/min%50-%55 VO2 max], and the sedentary control [SED] groups. All experimental groups performed a 12 week exercise program, including treadmill running on a 0° slope for 1 hr/day, 5 days/week. Fasting levels of circulating HMW adiponectin, testosterone, and insulin resistane index [HOMA-IR] were measured after the exercise program and, data were analyzed using one-way ANOVA, with Pearson's correlation was used to identify any possible relationship among the assessed variables. HMW adiponectin plasma concentrations increased significantly in the HI and MI exercise training groups [p<0.05]. HMW adiponectin was also found to be inversely related to HOMA-IR [r = -0.37, p= 0.003], insulin [r= -0.46, p= 0.008] and testosterone [r= -0.38, p= 0.03]. It can be conclude that exercise intensity appears to be an important parameter in increasing plasma HMW adiponectin levels in healthy male rats

[ effects of the intensity and volume of resistance exercises on the post-exercise blood pressure, heart rate and rate pressure product]

Cardiovascular diseases are the most common causes of mortality in the world. Increased blood pressure is one of the most important risk factors for cardiovascular diseases. Decreasing blood pressure due to exercise can reduce the risk of cardiovascular incidents. Thus, the objective of this study is to evaluate the effects of exercise on blood pressure, heart rate and rate pressure product. To evaluate the effects of intensity and volume of resistance exercises on the post-exercise cardiovascular responses, 10 young untrained non-athletic men [age: 22 +/- 0.8 years; height: 173.05 +/- 2.4 cms and weight: 67.2 +/- 3.4 kgs] participated in this study as the subjects. The subjects performed four exercise bouts in a randomized order. Each bout consisted of five exercises: arm curl, hamstring curl, squat, seated lat pull-down and bench press. The exercises were determined to be performed at three sets: SHORT volume of LOW 40% IRM [SL] and HIGH intensity 80% 1RM [SH] and at six sets: LONG volume of LOW 40% 1RM [LL] and HIGH intensity 80% 1RM [LH]. Blood pressure [BP], heart rate [HR] and rate pressure product [RPP] [product of HR and systolic BP] were measure before the exercise [baseline] and at the ten-minute intervals within 90minutes after each exercise. Then, the data were analyzed using two way ANOVA repeated measures and LSD post-hoc tests. Systolic BP was found to be affected by the volume and intensity of exercise and became lower during 10 to 60 minutes after the exercises [P<0.05]. However, Diastolic BP was not altered after the exercise bouts. HR was increased in 30 minutes after LL and SL, and within 60 minutes after SH and LH exercises [p<0.05]. In contrast, after SH and LH, RPP was increased over a period of 50 minutes. The intensity and volume of resistance exercises do not influence the magnitude and duration of post-exercise hypotension. Also, HR and RPP post-exercise are not affected by the resistance exercise volume