The present study was performed to clarify how a combined exercise/diet treatment could affect the expression level of the muscle fibronectin type III domain containing 5 (Fndc5) with respect to body fat mass. Male C57BL/6 mice were divided into 2 groups including low-fat (LF) and high-fat (HF) diets for 12 weeks. Then, LF fed (nonobese) and HF fed mice (obese) were divided into the following 4 groups: HF-Exercise, HF-Sedentary, LF-Exercise, and LF-Sedentary. The exercise group exercised on a motor-driven treadmill for 45 min/day, 5 days/week for 8 weeks. Mice were sacrificed 24 h after the final exercise session. Gastrocnemius muscle and the visceral adipose tissue were excised and frozen for the assessment of proliferator-activated receptor gamma coactivator 1 alpha (Pgc-1α) and Fndc5 messenger RNA (mRNA) and protein levels. Data indicated that protein level of muscle PGC-1α was decreased in HF versus LF groups and in obese versus nonobese mice. Moreover, Fndc5 mRNA levels were increased in the muscle tissue of HF versus LF groups and in obese versus nonobese mice. Also, in the gastrocnemius skeletal muscle, protein levels of FNDC5 were significantly higher in the HF fed mice, as compared with their low-fat fed counterparts, similar to what was observed for exercised versus sedentary mice. Overall, we found that the HF diet increased Fndc5 transcript levels in the skeletal muscle, but exercise had a minimal effect on the transcript level of Fndc5, whereas endurance training increased the protein content of FNDC5 in the skeletal muscle.

The connection between exercise and appetite has ramifications for acute energy balance and weight-management. Research would suggest that exercise training can transiently suppress appetite, particularly in overweight and T2D, healthy-weight individuals. However, the effect of such a transient appetite suppression on subsequent food intake may be restricted. The aim of this thesis was to investigate appetite responses to HIIT in obesity with T2D and to assess the effect of other exercise characteristics, as well as exercise intensity, in mediating these responses especially appetite hormones. Eighty individuals with type 2 diabetes (forty normal and forty obesity weight) performed HIIT trials, all in arandomly divided, in 8 groups (10 in each group) which included, obesity non-diabetic control, obesity diabetic control, normal weight diabetic control, obesity non-diabetic training, obesity diabetic training, normal weight, non-diabetic training, and normal weight diabetic training. Twelve-weeks HIIT sessions (each session of an interval training includes 60 s of high intensity training (85–95% of reserve heart rate)) + running for 60 s at low intensity (55–60% of reserve heart rate) were applied. Blood samples were taken at the beginning and after the fourth, eighth and twelfth week of the training. Data were analyzed using repeated variance analysis and Pearson correlation coefficient. The results showed that training reduced ghrelin plasma levels in obese diabetic subjects (P < 0.05). Training has reduced PYY plasma in healthy subjects (non-diabetic) with normal weight (P < 0.05). Training reduced plasma levels of PYY in diabetic patients with normal weight and increased it in obese diabetic and healthy subjects (P < 0.05). Training has increased GLP-1 plasma in obese diabetic and diabetic with normal weight groups (P < 0.05). Training reduced TNF-α in normal (non-diabetic) subjects with normal weight and diabetic and non-diabetic obese subjects. Collectively, the studies reported here suggest that appetite hormones differ between lean and obesity participants. The finding also suggested HIIT is more likely to elicit appetite hormones responses in obesity than in lean individuals with type 2 diabetes. Therefore, with caution, it is recommended that the high intensity interval training can be beneficial for these patients.

Context: Obesity is associated with endothelial dysfunction and cardiovascular diseases. Adiponectin and fibroblast growth factor 21 (FGF21) as hormones are highly contributive in cardiovascular system, while they are disrupted through obesity. Weight-bearing high intensity interval training (HIIT) as an effective procedure in preventing obesity-related complications in adults with obesity may be limited due to the subjects' muscular weakness and complications interfering walking. Aims: The purpose of this study was to assess the effectiveness of non-weight bearing all extremity HIIT (all ex. HIIT) on FGF21, adiponectin, nitric oxide (NO), and flow mediated dilation (FMD) in overweight and obese women. Methods: Thirty healthy overweight and obese sedentary university female students within 20.53 ± 1.50 age range and BMI ≥27 kg.m^-2 were assigned in two experimental and control groups. All ex. HIIT consisted of 4 × 4 min at 85–90% max HR with an interspersed with 3 × 3 min recovery per round at 70% max HR by upper and lower ergometers in a simultaneous manner on 10 weeks of four sessions of 40 min each. FGF21, adiponectin, NO, FMD, weight, waist and maximal oxygen uptake (VO_2max) were measured in pre and post-tests. Paired sample t-test and analysis of covariance are applied for statistical analysis. Results: Results indicated a significant increase in adiponectin (P ≤ 0.01) and FMD (P ≤ 0.001), while there existed no changes in FGF21 at (P ≥ 0.10) and NO (P ≥ 0.84). The weight and waist decreased at (P ≤ 0.001), and the VO_2max increased at (P ≤ 0.001). Conclusions: All ex. HIIT may be a safe alternative for overweigh and obese women who have complications with weight-bearing exercises, and may increase adiponectin, and improve the FMD, aerobic fitness, and body composition.