ABSTRACT

People with pre-diabetes have blood glucose levels that are higher than normal but not high enough for a diagnosis of diabetes. This condition raises the risk of developing type 2 diabetes, heart disease, and stroke.Pre-diabetes is sometimes called impaired glucose tolerance or Impaired Fasting（IGR）, including impaired fasting glucose（Impaired Fasting Glucose,IFG）and IGT（Impaired Glucose Tolerance, IGT）, is a necessary stage of a health people develop into a type 2 diabetes patients, and is a dynamic process in clinical. These people maybe come back to health or continue their symptom or develop to diabetes patients. Approximately 60% of patients with type 2 diabetes onsets before 5 years have impaired fasting glucose or impaired glucose tolerance unless they take steps to prevent or delay diabetes.

In recent years, researchers are focus on pre-diabetes patients’onset cause and whether it can be to prevent or delay. These issues get a full study which develops the formal theory and hypotheses of using exercise prescription and drug interference. At present there is already sufficient evidence that between physical activity and metabolic diseases there has a clear reverse relationship, including the prevention of type 2 diabetes.

The main purpose is to discuss appropriate exercise to delay or block the development of diabetes among pre-diabetes populations and reduce the risk of cardiovascular disease. The author use pre-diabetes populations decline in insulin sensitivity as the main entry point for discussion,including the fundamental of impaired glucose regulation and insulin resistance’s theory and exercise prescription for pre-diabetes populations.This book has a comprehensive and systematic review and the latest relevant research results. And it focuses on the effect of exercise prescription implementation for pre-diabetes populations.

The author’s main purpose is to use exercise prescription for the study of delay or block the development of diabetes among pre-diabetes populations. The research uses aerobic exercise（walking as a main exercise pattern）to study their relationship between aerobic exercise and Insulin sensitivity in IGR groups. The Impaired Glucose Regulation（IGR）includes Impaired Fasting Glucose（IFG）and Impaired Glucose Tolerance（IGT）.Both IGT and IFG are very strong risk markers for the development of Type-2 diabetes and are associated with increased CVD risk. IGR is the only phase to have to pass to become diabetes for a normal person. Most of IGR will develop type 2 diabetes if not to interfere. Few of intervention studies with aerobic exercise have been found on subjects with IGR. This research, by using the way of aerobics exercise prescription has studied the influence effects of the insulin sensitivity of IGR groups，and studied the influence effects according to the different types of the IGR and the risk factors of MS of the IGR groups having. And also has analyzed the relativity between the insulin sensitivity of intervention effect by aerobics exercise with the GLUT4 gene A/G Polymorphism and CETP gene TaqIB Polymorphism of IGR groups.

Based on questionnaires and regular physical examination, 130 people who exposed to the risk of IGR got their medical examination and Oral Glucose Tolerance Test（OGTT）with everyone’s consent. 90 IGR subjects were divided randomly into the experimental group（70 people）and the control group（20 people）. The individual Functional Capacity was got through limiting symptoms exercise test on the cycle ergometer. The researchers provided exercise prescription to the member of the experimental group. The style of the aerobic exercise was walking with the intensity of 40-50% F.C and the exercise duration 60 minutes（60min, 30min×2）every day. The subject was recommended to carry out his exercise prescription one hour later after his meal every time. The whole exercise period for the experimental group is 12 weeks, while the control group kept their life habit as usual without additional exercise. Under the same experimental circumstances，blood glucose, blood insulin, blood lipid and body mass of the experimental group and the control group were examined for three times, respectively at the time of just before the research, the 6th week and the 12th week during the whole period. In addition, GLUT4 gene A/G Polymorphism and CETP gene TaqIB Polymorphism were observed too.82 subjects（64 in experimental group, 18 in control group）finished all the process. During the whole process, three lectures about health knowledge were given to all subjects.

The experimental result indicated that：

（1）Both the experimental and the control group, Fasting and glucose stimulated serum insulin levels are all higher beyond the normal scope. The insulin endocrine index（HOMA2%B）and insulin resistance index（HOMA2 IR）increased, while the insulin sensitivity index decreased. There are no difference between two groups and genders.

（2）6 weeks aerobic exercise improved fasting insulin（P＜0.01），glucose-stimulated serum insulin（P＜0.05）and plasma glucose（P＜0.01）significantly．The plasma glucose in 62.5％ subjects decreased to normal level after 12 weeks aerobic exercise, and serum insulin decreased（P＜0.01）, insulin sensitivity index（P＜0.01）and insulin resistance index increased（P＜0.01）, adjustment of insulin β cell function（P＜0.01）.The control group had hardly significant change.

（3）As to the different kinds of IGR, aerobic exercise could make the blood glucose decreased significantly in I-IGT group, increased insulin sensitivity and decreased insulin resistance. It had good effect on the regulation of pancreas endocrinology.

（4）People with IGR had higher incidence of metabolic syndrome（MS）.Compared with insulin sensitivity, blood glucose and pancreas endocrinology regulation between the subjects from experimental group and those from Similar Metabolic Syndrome（SMS）, aerobic exercise made little different, and 12 weeks walking had not changed HDL-C of MS subjects obviously.

（5）Correlation analysis of aerobic exercise on insulin sensitivity and Gene Polymorphism indicated that 6 weeks aerobic exercise made the insulin sensitivity index（HOMA2%S）of AA group from GLUT4 gene A/G groups increased, while the insulin resistance index（HOMA2 IR）decreased significantly. AG type, AA type HOMA2%B increased after 12 weeks aerobic exercise, and the change of the prior was higher than the latter group.HOMA2 IR decreased greatly. In the CETP gene TaqIB Polymorphism groups, 12 weeks aerobic exercise brought significant changes on B1B2 type and B1B1 type before and after the research.

（6）The IGR group lowed their serum TG, TC and FFA, increased their blood HDL-C, and they benefited themselves by improving cardiovascular function and body mass through 12 weeks aerobic exercise.

Conclusions:

（1）The main changes of IGR abnormal insulin metabolism usually include that Fasting-insulin level and insulin level after the glucose tolerance go beyond the normal range, and the higher insulin endocrine index and the insulin resistance index, the lower insulin sensitivity index are major characteristic.

（2）12 weeks aerobic exercise could improve the metabolism dysfunction state of the IGR people efficiently by the way of improving high level serum glucose, low insulin sensitivity and insulin resistance. It also could regulate β-cell function and decrease the cardiovascular diseases risks for the IGR. The regulation effect on I-IGT is better than on I-IFG and IFG＋IGT.

（3）Aerobic exercise modified the insulin sensitivity mainly through improving the peripheral body tissue sensitivity to insulin at the early stage（6 weeks）. With the exercise intervention prolonged and the insulin resistance improved gradually, it will produce good adjustment of insulinβcells.

（4）The MS incidence of IGR people is high and aerobic exercise could shed light on the prevention through its good regulation function to blood glucose, insulin sensitivity, insulin resistance and βcells endocrine of MS or SMS people.

（5）6 weeks aerobic exercise had better regulation effect on blood glucose after glucose load than on fasting glucose, and influenced the modification of fasting insulin more efficient than that after glucose load.Good and entire intervention effects on blood glucose, insulin, insulin sensitivity and pancreas βcells were brought to the IGR people by 12 weeks aerobic exercise.

（6）The analyzed results of the relativity between the insulin sensitivity of intervention effect by aerobic exercise and the GLUT4 gene A/G Polymorphism and CETP gene TaqIB Polymorphism of the IGR groups showed that if the IGR had a different type of the GLUT4 gene A/G Polymorphism and CETP gene TaqIB Polymorphism, the reaction to an aerobic exercise intervention was different，thus，when an exercise prescription is made out, we should take into account the different types of his GLUT4 A/G and CETP gene TaqIB Polymorphism. We have got a new scientific basis for making out an exercise prescription according to this conclusion.

（7）12 weeks aerobic exercise could make serum glucose of most the IGR people restitute to normal level.

The research proved that aerobic exercise could prevent the IGR people from his progression to Diabetes efficiently, and the first pointed out that the intervention effect of aerobic exercise on the IGR insulin sensitivity had relationship with GLUT4 gene A/G Polymorphism and CETP gene TaqIB Polymorphism of the IGR groups.

Key words: IGR; Aerobic Exercise; Insulin Sensitivity; Gene Polymorphism

Correlation analysis Exercise Prescription

There are many a spec t s w or thy o f in-dep th s tudy in the implementation effects of exercise prescription for pre-diabetes populations.The authors wish this book's publication could contribute and inspire the researchers in the same field for the prevention and delay pre-diabetes populations. However, due to the ability of subjective and objective factors,some part of this book could be inevitably omissions and inadequacies. I urge readers to criticize corrections.

The contents of this book are based on the Fundamental & Applied Research Project（No. 2004040-The research of influence about aerobic exercise on human insulin sensitivity）of General Administration of Sport of China. Acknowledgement publication by Beijing Sport University.