Effect Of High-intensity Interval Training On Blood Lipolytic Hormone In Obese Young Women

Overweight,obesity and related diseases have become more and more common worldwide in the past decade.As we all know,exercise is an important way to prevent and treat obesity.Traditionally,it is believed that moderate intensity continuous training?MICT?is more beneficial for reducing fat,because the main energy-supplying substance of human body is fat.Current studies have proved that the effect of high intensity interval training?HIIT?and even very high intensity sprint exercise on reducing fat is more time-effective and even better for reducing abdominal visceral fat than that of medium and low intensity exercise on the basis of the same amount of exercise.But carbohydrate is the main energy-supplying substance in the process of HIIT.The reason why HIIT has better weight loss effect may be that it stimulates the body to produce more lipolysis hormones?adrenaline,noradrenaline,atrial natriuretic peptide,insulin-like growth factor-1,growth hormone?through high-intensity exercise,which promotes excessive oxygen consumption during the intermittent period of exercise and during the recovery period after exercise,thereby making more fat oxidative decomposition.Abdominal visceral fat has more lipolysis hormone receptors and is more sensitive to lipolysis hormones,which may be the reason why high-intensity exercise reduces more visceral fat than low-intensity exercise.Therefore,this study explored the mechanism of weight loss by observing the effect of HIIT on serum lipolysis hormones in obese young women.Objective:To explore the effect of HIIT on serum lipolytic hormones in obese young women by investigating the changes of lipolytic hormones before and after three HIIT and MICT interventions in 12 weeks and during three acute exercises.Methods:75 subjects were randomly divided into five groups:SIT group,HIIT₁₂₀ group,HIIT₉₀ group,MICT group and CON group,15 in each group.SIT group was a sprint training group?sprint for 6 seconds,rest for 9 seconds,40 groups?;HIIT₉₀ group was trained with90%V?O_2max intensity for 4 minutes,rest for 3 minutes,repeat several groups to overcome 200KJ mechanical work;HIIT₁₂₀ group exercised at 120%V?O_2max intensity for 1 minute,rested intermittently for 1.5 minutes,and repeated several groups to overcome 200 KJ mechanical work;MICT Group continued to exercise at 60%V?O_2max intensity until 200 KJ mechanical work was overcome;CON group was the control group,without exercise.The exercise groups used bicycle,training three times a week in the first four weeks,and four times a week in the last eight weeks,for a total of 12 weeks and 44 times.The body weight,body mass index and body fat percentage were measured before and after 12 weeks.Fasting elbow venous blood was collected in the morning,and epinephrine?EPI?,noradrenaline?NA?,growth hormone?GH?,insulin-like growth factor 1?IGF-1?,atrial natriuretic peptide?ANP?were measured.Before,during and after 12-week training,blood samples were collected from elbow veins before,immediately after and 3 hours after the first training,the 20th training and the 44th training respectively,EPI,NA,GH,IGF-1 and ANP were measured.Results:After 12 weeks of intervention,the concentration of ANP in SIT group,HIIT₁₂₀group and HIIT₉₀ group was lower than before intervention in the morning?P<0.05?,but there was no significant difference between MICT group and CON group before and after 12weeks?P>0.05?.There was no significant difference in EPI,NA,GH and IGF-1 levels in the morning quiet fasting blood between the groups before and after 12 weeks?P>0.05?.At the first,20th and 44th training,GH in SIT group,HIIT₁₂₀ group,HIIT₉₀ group and MICT group immediately after exercise was significantly higher than before exercise?P<0.01?,while GH in each group recovered to pre-exercise quiet level 3 hours after exercise?P>0.05?.At the 1st and 20th training,compared with before exercise,EPI in HIIT₁₂₀20 and HIIT₉₀groups increased significantly immediately after exercise?P<0.01?,and returned to pre-exercise quiet level 3 hours after exercise.There was no significant difference in EPI between SIT group and MICT group immediately after exercise and 3 hours after exercise compared with before exercise?P>0.05?.At the 44th training,EPI in SIT group,HIIT₁₂₀group and HIIT₉₀ group increased significantly immediately after exercise?P<0.05?,and restored to a quiet level 3 hours after exercise,while EPI in MICT group had no significant difference immediately after exercise and 3 hours after exercise compared with before exercise?P>0.05?.At the first,20th and 44th training,there were no significant differences in NA,ANP and IGF-1 before,immediately after and 3 hours after exercise?P>0.05?.Conclusion:Both HIIT and MICT can increase GH secretion in blood of obese people,which may be the reason why both of them have the effect of reducing fat.In addition,HIIT can better promote blood EPI secretion in obese people,but MICT which overcomes the same mechanical work has no such effect,which may be the reason why HIIT has better effect on reducing abdominal visceral fat than MICT.