Effect of one or two sessions per day of physical activity, with equal intensity and duration, on adiponectin and insulin resistance in sedentary middle-aged men

Previous studies suggest that, the regular physical activity improves insulin resistance. However, the effect of training sessions a day is not clear in this regard. The aim of this study was to investigate the effect of one or two sessions a day of exercise training, with equal intensity and duration, on insulin resistance in sedentary middle-aged men. 30 sedentary middle-aged male volunteers (age=43. 6±6. 5 yr, weight=80. 4±13. 6kg, height=174. 1±5. 5cm, BMI=26. 5±3. 6kg/m2،VO2max=35. 46±6ml/kg) randomized to the control (n=10), one session a day (n=10) and two sessions a day training group (n=10). Exercise program consisted of 16 weeks, five days a week, tread mill running which was implemented as one (30 minutes) or two sessions (2×15 minutes) a day. Training intensity was 40-50% of HRmax at first week and reached to 70-80% at 16th week of the training. Measurements of fasting blood samples (insulin, glucose and adiponectin), insulin resistance, cardiorespiratory fitness, abdominal obesity and BMI were obtained at baseline and post exercise. Paired t test and analysis of Variance were used to analyze the data. After 16 weeks of training, compared with the control group, a significant reduction in blood glucose, abdominal obesity and BMI, and a significant increase in cardiorespiratory fitness were observed in the both experimental groups; whereas insulin resistance remained unchanged, and adiponectin was significantly increased only in the one session a day training group. based on the findings it seems that, dividing the physical activity session in two shorter parts can improve glucose profile, cardiorespiratory fitness and obesity indicators the same as a continuous exercise session. But in terms of increased adiponectin and decreased abdominal obesity, continuous exercise session is more effective.