Abstract:

Objective
 To explore the effects of 8-week aerobic interval training on cardiac function and physical fitness in obese teenagers and to provide evidence for formulating special exercise prescription for obse teenagers.Methods Forty male obese teenagers (BMI ≥ 25) were randomly divided into control group (n=20) and exercise group (n=20).People in exercise group conducted a 8-week (twice per week,50-60 min per session) aerobic interval training and people in control group maintained their routine lifestyle.The heart rate (RHR),systolic blood pressure(SBP),diastolic blood pressure(DBP),maximal oxygen uptake (VO2max),percentage of body fat and cardiac function parameters including left ventricular end-systolic volume (LVESV),left ventricular end-diastolic volume (LVEDV),stroke volume (SV),cardiac output (CO),fractional shortening (FS) and left ventricular ejection fraction (LVEF) were determined by echocardiography  before and after the intervention in two groups.Results There were no significantly differences of indicators between two groups before test.After test,the percentage of body fat,RHR and SBP in exercise group were decreased (P<0.05 or P<0.01);VO2max  was increased (P<0.01);the  LVEDV,SV,LVEF and FS were elevated (P<0.05 or P<0.01) and CO had no significant difference compared with before test;but the indexes in control group showed no significant changes.The percentage of body fat,RHR and SBP in exercise group after test  were lower than those in control group(P<0.05 or P<0.01);VO2max, LVEDV,SV,LVEF and FS  were higher than those in control group(P<0.05 or P<0.01).Conclusion Aerobic interval training may improve cardiac function and physical fitness in obese teenagers.

Key words:  aerobic interval training;obesity;teenager;cardiac function;physical fitness