Obesity in adult population is related to obesity during their childhood. In addition, obese adolescents are at risk of developing obesity as adults, who tend to have abnormal lipid and glucose levels (1). Obesity is one of the major risk factor for developing cardiovascular diseases (14) Altered metabolism of lipids is observed in obese individuals. (3) ) It has been suggested that high levels of cholesterol among children and adolescents is positively associated with development of future coronary heart disease.(5)In obese children and adolescents, increased low density lipoprotein (LDL) cholesterol and low levels of High density lipoprotein (HDL) cholesterol occur as abnormal lipid profile.(4,18)Among these, high density lipoprotein cholesterol is an important marker for risk of developing cardiovascular disease.(6) High density lipoprotein level alone is indicative of development of coronary artery disease and there is negative relationship between level of high density lipoprotein and occurrence of cardiovascular abnormality. (7) In contrast to increased low density lipoprotein levels, increased high density lipoprotein level provides protection against atherosclerosis process. High density lipoprotein performs this protective function by removing extra cholesterol from macrophages in the arterial walls to the liver for excretion through bile. This process is known as Reverse cholesterol transport. Further, high density lipoprotein (HDL) also has anti-oxidant properties. (2, 19) In addition to cardio protective action, high density lipoprotein protects against Alzheimer’s disease and dementia. So, alteration in serum levels of high density lipoproteins will affect the future management of cardiovascular and degenerative neuronal disorders. (7) High density lipoprotein levels are elevated in those who are physically active. (8) Exercise has been identified as effective treatment for maintaining normal lipid levels in adolescents. (9) So, it has been widely accepted that regular aerobic training improves high density lipoprotein levels and thus protects against cardiovascular abnormalities.(8) Resistance exercise also has shown improvements in High density lipoprotein levels.(10)
The purpose of this study is to compare the effects of aerobic and resistance training on high density lipoprotein levels in obese adolescent males.
Aerobic exercise training and resistance exercise training are independent variables for this study.
Plasma high density lipoprotein cholesterol level
H1: There will be significant change in high density lipoprotein level following aerobic exercise training.
Ho1: There will be no difference in change in high density lipoprotein level following aerobic exercise training.
H2: There will be significant change in high density lipoprotein level following resistance exercise training.
Ho2: There will be no difference in change in high density lipoprotein level following resistance exercise training.
H3: There will be significant difference in change in high density lipoprotein levels between both groups.
Ho3: There will be no difference in change in high density lipoprotein levels between both groups.
It is assumed that participants will not change their lifestyle and diet habits during study duration. Participants are not taking medicines which can affect the outcome and will give best efforts during exercise.
In this study participants will be male obese adolescents only.
This study covers limited age group. (13-15 years)
Study focuses on obese male individuals only.
Plourde (2002) investigated impact of obesity on glucose and lipid profiles in adolescents at different age groups in relation to adulthood. This study was done in two stages. In the first stage participants were classified in overweight group and control group according to the Body Mass Index (BMI).BMI ≥85th percentile was considered overweight, BMI ≥95th percentile was considered obese and BMI ≤85th percentile were taken as controls. Glucose and lipid profiles were measured in these subjects. Association between glucose and lipid profiles with anthropometric measurements was founded. Second study was retrospective prospective longitudinal study to determine association of obesity in adolescence with that of obesity in adulthood and obesity related risk factors. Seven different age groups from 9 to 38 years were studied from 1974 to 2000. It was concluded that lipid profile and glucose are related to anthropometric measures in adolescents. In addition to this obesity in adolescents of 13-15 years was found important factor for obesity in adulthood. (1)
Zhang et al. (2014) studied the association of simple anthropometric indices and body fat with early atherosclerosis and lipid profiles in Chinese adults. Purpose of this study was to determine the best adiposity index to predict the early atherosclerosis and abnormal lipid profiles. In this study 2,063 women and 814 men participated. Assessment for body mass index, waist circumference, waist to hip ratio and waist to height ratio were taken. Along with this intima media thickness of common carotid artery, internal carotid arteries and bifurcation were measured. Fasting Lipid profiles were assessed. Statistical analysis was conducted to know the relation between the measures. It was found that waist circumference, waist to hip ratio and waist to height ratio were closely related to intima media thickness and lipid profiles. Based on the results, it was concluded that abdominal anthropometric measures were associated with lipid profile and atherosclerosis. Waist circumference was suggested to be the best measurement for its simple use.
Takami et al. (2001) found relation between body fat distributions, metabolic abnormalities and carotid atherosclerosis. In this study, it was hypothesized that the intra-abdominal fat is more important factor over general adiposity to predict metabolic abnormalities and atherosclerosis. This cross sectional study included 849 Japanese men with 20-70 years of age. Body mass index was taken as general adiposity measurement. Waist circumference, waist-hip ratio and computed tomography were taken as measure of intra-abdominal fat distribution. Relation between these factors and lipid profile, glucose tolerance, insulin resistance and intima media thickness was analyzed. Results showed association between these factors. It was concluded that body mass index and waist hip ratio are better clinical predictors of carotid atherosclerosis.
Chang, Liu, Zhao, Li and Yu (2008) examined the effect of supervised exercise training on metabolic risk factors and physical fitness in Chinese obese children in early puberty. In this study, 49 obese children of 12 to 14 year of age were divided into control and exercise groups. Exercise group was given 9 to 12 months of supervised exercise training and health education once every 3 months. Control group was given only health education. Improved insulin sensitivity and associated factors of metabolic syndrome along with slowed progression of obesity was observed in exercise group. It was concluded that obesity and physical inactivity continue in adulthood and are risk factors for cardiovascular and other chronic diseases. (11)
Flynn et al. (2013) studied factors associated with low High density lipoprotein cholesterol in middle school children with mean age of 11.6 years and observed that overweight or obesity was related to lower levels of high density lipoproteins. There were1104 participants in this study. Participants were analyzed with laboratory screening of lipid profile, blood pressure and physical assessment of body mass index and physical activity. It was concluded that increased fitness and healthy weight management are more likely to increase high density lipoprotein levels in children and adolescents. (6)
Kelley and Kelley (2006) studied the effects of aerobic exercises and diet on lipids and lipoproteins in children and adolescents.12 Randomized control trials containing 389 subjects with age group of 5 to 19 years and minimum 4 weeks of exercise interventions were included in this meta-analysis. Effects were aerobic training was observed on high density lipoproteins, low density lipoproteins, triglycerides and total cholesterol. Results showed significant reduction in triglyceride levels along with trend of elevated high density lipoproteins in overweight and obese subjects. (5)
Mohammadi et al. (2014) studied the effect of 12 week of aerobic training on homocysteine, lipoprotein A and lipid profile levels in sedentary middle aged men. Subjects were randomly divided into control and aerobic training group. There were 12 male subjects in each group having 40-60 years of age. Aerobic exercise training was given to the aerobic group progressively increasing the duration from 20 to 60 minutes per session. Intensity was increased from 60% of maximum heart rate to 75% of maximum heart rate. Results showed significant increase in high density lipoprotein level and reduction in homocysteine, lipoprotein A and triglycerides level after 12 weeks of intervention of aerobic exercise.
Tseng et al. (2013) conducted a pilot study to find out the more effective exercise training in increasing high density lipoprotein levels. There were 40 obese men of 18-29 years of age included in the study. Participants were allotted to four groups. These were Aerobic exercise group, Resistance exercise group, combined exercise group and control group. Exercise intervention was done for 12 weeks. It was observed that either aerobic or resistance training alone significantly raised high density lipoprotein levels, but combined exercise was most effective. (10)
Falham et al. studied the effects of endurance and resistance exercise training on plasma lipoprotein levels in 45 healthy elderly women aging 70-87 years. Subjects were assigned to 3 groups randomly. Endurance training group was intervened with walking exercise and progressed from 20 to 50 minutes duration over the period of 3 weeks. Resistance exercise group performed 1 to 3 sets of 8 different exercises at 8 repetitions maximum. Control group did not perform any exercise and continued their normal activity. Interventions lasted for 10 week duration. In the 11th week, lipid profile was measured. Results showed improved levels of high density lipoprotein level and reduced triglyceride level in both endurance and resistance exercise groups. It was concluded that the high intensity exercise alone can alter the lipoprotein levels.
Koozehchian et al. (2014) identified the role of exercise training on lipoprotein profiles in adolescent males. In this study 45 subjects participated and they were divided into 3 groups. They were swimmers, soccer players and non-athlete; physically active individuals (control). Each group consisted of 15 individuals. Swimmers and soccer players were participating in their sport activities for at least 3 months immediately before the initiation of the intervention. Swimmers performed supervised swim of 60 minutes for 3 days/week. Soccer players performed supervised soccer training consisting of warm up, stretch, endurance running, team games, strengthening and match for 60 minutes per session for 3 days/week. These interventions lasted for 12 weeks. Plasma low density lipoprotein, Apo-lipoproteins, very low density lipoprotein, high density lipoprotein, total cholesterol, and triglyceride levels were measured pre-training and post-training. Increase in mean high density lipoprotein levels and reduction in low density lipoprotein level were found in two interventional groups. From the results, it was concluded that regular swimming and soccer training reduces the risk of cardiovascular disorders in adolescents.
Kodama et al. conducted meta-analysis to identify the effect of aerobic exercise training on serum levels of high density lipoprotein cholesterol. Only randomized control trials were reviewed. These studies were performed on individuals of ≥20 years of age. Studies which had at least 8 weeks of training duration and pre-training and post-training high density lipoprotein cholesterol measurements, were included in the meta-analysis. Sample size of the study varied between 9 to 200 and 1404 of total subjects. Analysis of 25 studies indicated that the mean difference in high density lipoprotein cholesterol change is associated with exercise duration. Approximately, 1.4 mg/dl net rise corresponded to10 minutes increased exercise duration. Study indicated that aerobic exercise is associated with modest elevation in plasma high density lipoprotein level. Duration of the training session was found to be most important factor for prescription.
Filho et al. (2011) investigated the effects of exercise training on plasma levels and functional properties of high density lipoprotein cholesterol in the metabolic syndrome.30 sedentary subjects were classified into study group which included 20 subjects with metabolic syndrome and control group consisting of 10 subjects without metabolic syndrome. The study group was intervened with moderate intensity exercise training on bicycle ergometer for 3 months. Blood samples were taken at baseline and after intervention. Results showed reduced triglyceride levels in study group. No significant difference was observed in low density lipoproteins and high density lipoproteins. However, changes were observed in high density lipoprotein sub fractions. It was concluded that emphasis should be given on functional aspects of lipoproteins along with plasma levels. (12)
Gomez et al. (2013) studied the effect of 10 weeks endurance and resistance training on regional fat mass and lipid profile. Study was done on 26 healthy young men aging 22.5±1.9 years. Subjects were randomly divided into endurance, resistance and control group. Baseline data for lipid profile and dual energy x-ray absorptiometry to calculate the total and regional fat masses were taken. During 10 week exercise training endurance group performed running and cycling for 90 minutes per session. Exercise intensity was determined based on the initial cardiorespiratory assessment. Intensity ranged between ventilator threshold 1 and 2.Resistance group performed 5 different exercises at 50-90% of 1 repetition maximum with 90 seconds rest in between sets. It was found that change high density lipoprotein was associated with total lean mass and weight, and resistance training was associated with increased lean body mass.
Stoedefalke (2007) studied the effects of exercise training on blood lipids and lipoproteins in children and adolescents. The purpose of the study was to determine the effect of exercise on total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides. Out of the 14 studies included in the review, positive alteration in the blood lipids and lipoproteins was found in 6 studies. No alteration in lipid profiles was observed in 4 studies. Negative effect on high density lipoprotein was observed in one study. However, there was overall improvement in lipoprotein profile. It was concluded that the equivocal result might be due to various methodological problems, such as low sample size, less than 8 weeks of intervention and inadequate exercise volume.
Male adolescents age 13-15 years having Body Mass Index (BMI) of more than or equal to 85 percentile for age, classified as overweight and obese according to Center for Disease Control (CDC) will be included in the study (ped).Subjects with cardiovascular diseases and systemic diseases will be excluded from the study. About 30 subjects will participate in the study.
Informed consent will be taken from the parents of the subjects. Subjects’ age, height, weight, Body mass index, Waist circumference, Heart rate, Blood pressure and plasma High Density Lipoprotein cholesterol will be measured at rest.
All subjects will undergo physician’s examination and health questionnaire. Subjects having cardiovascular, hepatic and other systemic disease will be excluded from the study. Participants’ age, height, weight and Body Mass Index will be recorded. Subjects having BMI of more than or equal to 85th percentile will be included in the study.(ped) Subjects will be asked to not to change their dietary habits during the training period. Subjects will be randomly assigned to aerobic training group and resistance training group.
Subjects will be asked to have 12 hour fasting period before baseline measurements. Baseline data of Height and weight will be measured and BMI will be calculated as per weight/height2. (kilogram/meter2) and BMI percentile will be calculated according to Centers for Disease control BMI for age growth chart. Subjects will be given rest for the 10 minutes. Heart rate and blood pressure will be measured with palpation and auscultation method respectively, in sitting position. Venous blood will be collected for measuring plasma High density lipoprotein levels.
Participants assigned to aerobic exercise training group will exercise 3days per week. Each session will include 10 minutes warm up exercise, 40 minutes of treadmill walking at 70-75% of maximum heart rate. (1) Maximum heart rate will be calculated as 220-age of the subject. This will be followed by cool down period and stretching for 10 minutes. Participants allotted to resistance exercise training will exercise for 3 days per week. Each session will have 10 minute of warm up period,40 minutes 50-75% of 1 Repetition maximum.(2) and cool down period for 10 minutes.
Both groups will continue the exercise for 10 weeks. (Banz et al.) Following the intervention for 10 weeks, BMI, waist-circumference will be measured. Venous blood will be collected to measure the plasma high density lipoprotein levels .Statistical analysis will be done to compare pre and post exercise values and to compare the values in both the groups.