The effect of eight weeks interval and continuous walking on serum levels of dipeptidyl peptidase-4 and insulin resistance index in obese girls aged 9-11 years old

Dipeptidyl-peptidase-4 (DPP-4) has been proposed as a bridge between obesity and insulin resistance (IR). The aim of this study was to investigate the changes in serum levels of DPP-4 and HOMA2-IR after eight weeks of interval and continuous-walking in 9-11 year-old obese girls. thirty two-obese girls (age: 9.62±0.75 years and BMI-percentile: 97.38±1.40%) volunteered in this study and were assigned to interval (n=12), continuous (n=11) and control (n=9) groups. The training were performed for 8-weeks, 3-sessions per week (30-min walking in the continuous and interval groups with 60-75%HRmax and 70-85%HRmax, respectively). Interval-walking included 2-min of walking and 1-min of active rest. After 10-hours of fasting, blood sampling was performed before the beginning of training and 72-hours after the last session. The paired t-test was used to examine the within-group changes. Eight weeks of continuous and interval training did not significantly change the levels of DPP-4, insulin, glucose, and HOMA2-IR compared to the control group. Compared to the control group, the interval training resulted in improvement of the body weight, BMI, and BMI percentile (p=0.004, p=0.019, p=0.022), while the BMI only tended to decrease in the continuous training group (p=0.077). It seems that the improvement of the body composition due to the protocol used in this study was not sufficient to make significant changes in the HOMA2-IR and DPP-4 in early-pubertal obese girls.