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THE EFFECT OF A 10-WEEK TAE-BO INTERVENTION PROGRAM
ON CARDIOMETABOLIC DISEASE RISK FACTORS IN
OVERWEIGHT AND OBESE FEMALES AT THE UNIVERSITY OF
ZULULAND
Musa Lewis Mathunjwa
Dissertation submitted in partial fulfillment of the requirements for the degree of
Masters in Science (Sports Science)
Department of Biokinetics and Sports Science,
Faculty of Science and Agriculture, University of Zululand
Supervisor: Prof. Stuart Semple
Co-supervisor: Dr. Corrie du Preez
October 2013
2
ABSTRACT
Background and aims: The prevalence of obesity, sedentary life styles and associated
cardiometabolic disease (CMD) risk are increasing among black African women and require
urgent attention in the form of preventative strategies. To date, there is limited scientific
evidence highlighting the efficacy of Tae-bo as an intervention for reducing CMD risk.
Regular physical activity leads to significant changes in terms of the reduction of CMD risk.
The present study was designed to investigate the effect of a 10-week Tae-bo intervention
program on cardiometabolic disease risk factors in overweight and obese females.
Methods: Sixty previously sedentary participants who were overweight (BMI > 25–29.9
kg.m-2) or obese (BMI ≥ 30–39.9 kg.m-2) were recruited for the study. Participants performed
a 10-week aerobic (Tae-bo) program 60 min/day for three days a week at moderate intensity
(40–60% HRR) for the first five weeks and high intensity (60–70% HRR) for the last five
weeks. The intensities were established by the use of Karvonen‟s formula. Anthropometric
parameters, blood pressure, fasting glucose and lipoproteins (both using finger prick) were
measured at baseline, after six weeks and 24 hours after completion of the 10-week program.
Data was analysed using repeated measures analysis of variance and a Tukey Post hoc test.
Results: The prevalence of metabolic syndrome was 26.7% pre-intervention and decreased to
16.3% post intervention. There was a statistically significant (p ≤ 0.05) improvement in all
the parameters measured, mid and post intervention. Some effect sizes, following the
intervention, include: weight (0.3), BMI (0.2), TC/HDL (-0.2).
Conclusion: A 10-week Tae-bo training program was effective in reducing cardiometabolic
disease risk factors in overweight/obese female university students.
KEY WORDS: Aerobic, Tae-bo, overweight, obese, cardiometabolic disease risk.
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DECLARATION
I, the undersigned, hereby declare that the work contained in this dissertation is my own
original work and that I have not previously submitted it in its entirety or in part at any
university for a degree.
Signature: Date:
4
DEDICATION
I dedicate this dissertation to my parents Thomas Mathunjwa and Thoko Dlamini.
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ACKNOWLEDGEMENTS
It is a pleasure to thank those who made this dissertation feasible through their assistance and
support;
Foremost I would like to sincerely thank my supervisor, Prof Stuart Semple and co-
supervisor Dr Corrie du Preez for their continual guidance. Their patience and
expertise were genuinely appreciated;
The Biokinetics Honours students and BSc Sports Science Students for their
assistance throughout the intervention;
The participants from the University of Zululand, I could not have completed my
study without their willingness to participate;
Mandi Semple for editing and proof reading the dissertation;
The University of Zululand Research Committee and the Community Engagement
Working Group (CEWG) for funding this research project.
Lastly, this study could not have been possible without God. Thank you.
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TABLE OF CONTENTS
CONTENTS PAGE
ABSTRACT 2
DECLARATION 3
DEDICATION 4
ACKNOWLEDGEMENTS 5
TABLE CONTENTS 6
LIST OF ABBREVIATIONS 8
LIST OF RESEARCH OUTPUTS 9
CHAPTER 1: INTRODUCTION 10
1.1 Introduction 10
1.2 Problem Statement 15
1.3 Study Aim 15
1.4 Research Hypothesis 15
1.5 Structure of Dissertation 15
CHAPTER 2: LITERATURE REVIEW 16
2.1 Introduction 16
2.2 Anthropometry 16
2.3 Lipoprotein 25
2.4 Glucose 33
2.5 Blood Pressure 40
CHAPTER 3: SCIENTIFIC PUBLICATION 46
CHAPTER 4: CONCLUSION 65
4.1 Conclusion 65
4.2 Study limitations 66
REFERENCES 67
APPENDICES 78
Appendix A: Informed Consent 78
Appendix B: Data sheet 83
Appendix C: General Health History Questionnaire 84
Appendix D: Publication Letter 87
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LIST OF FIGURES
Figure 1.1 Cardiometabolic risk factor 12
Figure 1.2 Association of physical activity with metabolic syndrome 13
Figure 1.3 Association of exercise with risk of death 13
LIST OF TABLES
Table 2.1 Anthropometric Measurements 18
Table 2.2 Lipoproteins 27
Table 2.3 Glucose 35
Table 2.4 Blood pressure 41
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LIST OF ABBREVIATIONS
ACSM American College of Sports Medicine
BMI Body mass index
BP Blood pressure
CMD Cardiometabolic disease
CVD Cardiovascular disease
DBP Diastolic blood pressure
HDL-C High density lipoprotein cholesterol
HR Heart rate
HRR Heart rate reserve
LDL-C Low density lipoprotein cholesterol
Min Minutes
mmHg Millimeters of mercury
PAR-Q Physical activity readiness questionnaire
RHR Resting heart rate
RPE Rating of perceived exertion
SBP Systolic blood pressure
SD Standard deviation
WC Waist circumference
WHO World Health Organization
WHR Waist to hip ratio
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LIST OF RESEARCH OUTPUTS
Publication
Mathunjwa M., Semple S. and Du Preez C. (2013). A 10-week aerobic exercise program
reduces cardiometabolic disease risk in overweight/obese female African university students.
Ethnicity and Disease, Volume 23, Spring, pp143-148. (Manuscript number: MS #12-144,
see Chapter 3 and Appendix D)
International Conference Proceeding
Mathunjwa ML, Semple S and Du Preez C. (2012). The effect of a 10-week Tae-bo
intervention program on physical fitness and health related risk factors in overweight/obese
females. Biokinetics Association of South Africa Conference.SAJSM.24(3)98.
Local Conference Proceeding
Mathunjwa ML, Semple S. and Du Preez C. (2012). The effect of a 10-week Tae-bo
intervention program on Physical fitness and health related risk factors in overweight/obese
females 7th Science Symposium, University of Zululand, South Africa, 2 November 2012.
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CHAPTER 1
INTRODUCTION
South Africa is facing an increase in non-communicable diseases as a result of overweight
and obesity (Unwin et al., 2001). Being overweight (BMI ≥ 25.0 kg/m2) or obese (BMI ≥
30.0 kg/m2) increases the risk of diseases such as type 2 diabetes, osteoarthritis, sleep apnea,
cardiovascular diseases, and various cancers (James et al., 2004).
According to the World Health Organisation (2013), the global epidemic of overweight and
obesity is estimated to be approximately 1.4 billion. The prevalence of overweight and
obesity in developed countries like the United States is approximately 32.2% in women and
26.6% in men above 20 years of age (Ogden et al., 2006). Research in South Africa indicates
that the prevalence of both overweight and obesity is 56% in females and 29% in males aged
above 15 years (Puoane et al., 2002). It has also been shown that 56.3% of the South African
population is overweight, of which 33.6% are obese, and 6.2% are morbidly obese (BMI ≥ 40
kg/m2) (Ogden and Carrol, 2010). Reddy et al. (2012) in the 2nd South African National
Youth Risk Behaviour Survey of 2008 found that obesity in female adolescents increased by
2.5% since the first survey was conducted in 2002. Rossouw, Grant and Viljoen (2012) in
their studies indicated that 13% of children are overweight and 3.3% are obese and many
obese children are likely to grow up to be obese adults (Ogden et al., 2006).
Research findings have shown that Black South African women have the highest prevalence
of overweight and obesity (58.5%), followed by women of mixed ancestry (52%), White
women (49.2%) and then Indian women (48.9%) (Puoane et al., 2002). Women living in the
urban areas have higher BMIs than those living in the rural regions and in both of these
categories, while increases in BMI were found to be related to increases in age (Puoane et al.,
2002). Abdominal obesity prevalence (using waist to hip ratio of 1.0 and 0.85 for men and
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women respectively) was found to be 42.2% in women and most prevalent in urban African
and women of mixed ancestry (Puoane et al., 2002).
Overweight and obesity is fundamentally caused by energy imbalance between calories
consumed and calories expended (World Health Organisation, 2005). Although adipose tissue
is necessary and serves as the body‟s fuel reserve, too much adipose tissue is harmful (Klein,
2001). The intra-abdominal visceral deposition of adipose tissue, which characterises upper
body, central obesity (assessed by waist circumference and/or waist: hip ratio) is a major
contributor to the development of hypertension, elevated plasma insulin concentrations
(insulin resistance), hyperglycaemia and hyperlipidaemia (Alberti et al., 2009). Metabolic
syndrome (MetS) is often called cardiometabolic disease and consists of a clustering of risk
factors such as elevated visceral obesity, glucose intolerance, elevated triglycerides, reduced
high density lipoprotein cholesterol and hypertension (Scaglione et al., 2010).
The combination of obesity, physical inactivity and consumption of an atherogenic diet has
been found to be a leading cause of insulin resistance (Grundy et al., 2005). Cardiometabolic
risk (CMR) is associated with cardiovascular disease (CVD) and type 2 diabetes, obesity,
insulin resistance, hyperglycemia, physical inactivity, smoking and hypertension (Scaglione
et al., 2010). (See Figure 1.1). Lipoprotein abnormalities, including elevated triglycerides,
low HDL cholesterol and increased LDL particles are common in individuals with CMD.
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Figure 1.1 Cardiometabolic risk factors (John et al., 2008)
An individual is classified as being sedentary if he/she engages in less than 30 minutes of
moderate intensity physical activity 5 days of the week (America College of Sport Medicine,
2010). A survey done in 2003 by the South African Department of Health and the South
African Medical Research Council, showed that 62% of South African men and 48% of
South African women aged 15 years and older follow a sedentary lifestyle (Reddy et al.,
1998). It has also been shown that 33% of South African boys and 42% of South Africa girls
are sedentary (Reddy et al., 1998). From the above it is clear that the majority of South
African adults and children are not meeting the recommended daily physical activity
guidelines.
Physical inactivity increases the risk of all-cause and cardiovascular mortality (United States
Department of Health and Human Services, 2008) and may contribute towards non-
communicable diseases such as coronary heart disease, type 2 diabetes and high blood
pressure (Daniels et al., 2005) (Figure 1.1). In addition, it negatively effects serum lipoprotein
profiles and increases the risk for asthma and arthritis (Dietz, 2004). A sedentary lifestyle
effects insulin and glucose metabolism which influences the atherosclerotic processes
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(Chandrashekhar and Anad, 1991). Globally, it is estimated that inactivity causes
approximately 6% of coronary heart disease, 7% of type 2 diabetes, 10% of breast cancer,
10% of colon cancer and 9% of premature mortality (Lee et al., 2012). Health individuals
who are not fit have a mortality risk that is 4.5 times that of the most fit (Myers, 2003)
(Figure 1.3). It is clear that improving ones level of fitness reduces the risk for metabolic
syndrome (Figure 1.2) and reduces the risk of mortality (Figure 1.3).
Figure 1.2 Association of physical activity with metabolic syndrome (Brageet al., 2004),
Figure 1.3 Association of exercise with risk of death (Rigatto and Parfrey, 2006)
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Approximately 3% of men and 4% of South African women 30 years and older may die due
to lack of physical activity (Joubert et al., 2007). The World Health Organisation (2004)
recommends for health benefits, that all adults should do at least 30 minutes or more of
moderate intensity aerobic physical activity daily and that sixty minutes of daily physical
activity is required to prevent weight gain. This should either happen in a single session or
„accumulated‟ in multiple bouts, each lasting at least 10 minutes at a time (American College
of Sport Medicine, 2010).
Physical activity is one of the approaches to prevent and manage individuals who are
overweight or obese. Research has shown that the combination of regular exercise and dietary
intervention is effective for weight loss and weight control, improved self-efficacy and better
long-term weight loss maintenance in overweight and obese people (Donnelly et al., 2004).
Strong evidence shows that physical activity reduces the risk of all-cause and cardiovascular
mortality, stroke and metabolic syndrome (Lee et al., 2012).
There are several modes of exercise to improve cardiorespiratory fitness such as running,
taekwondo, karate, boxing, hip-hop dancing, etc. To the best of the author‟s knowledge, there
are only two studies investigating Tae-bo as an exercise intervention. One study investigated
kinaesthetic perception and the potential ability to sustain or improve performance in athletes
such as dribbling, shooting and footwork (Roby, 2010). Another study by Milenkovic and
Veselinovic (2010) investigated the effects of experimental Tae-bo training on coordination
development in young women. No study has addressed the efficacy of group Tae-bo training
as an intervention to reduce cardiometabolic disease risk in previously sedentary, overweight
Black African university females, between 20 and 30 years of age.
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1.2 Problem Statement
Black African women have a higher prevalence of overweight and obesity which in turn
increases their risk of disease (United States Department of Health and Human Services,
2010). Although anecdotal, it is fair to say that obese African University of Zululand students
are by and large sedentary, and there is currently very little scientific information available
looking at exercise interventions in this population.
1.3 Study Aim
To determine if a group based 10-week Tae-bo intervention of 30 sessions would be effective
in reducing cardiometabolic disease risk in Black African females.
1.4 Research Hypothesis
There will be a significant reduction in cardiometabolic disease risk factors in
overweight/obese Black African female students following a 10-week Tae-bo intervention
program.
1.5 Structure of Dissertation
The dissertation is divided into sections. Chapter 1 contains the introduction, Chapter 2 a
concise review of the relevant literature, Chapter 3 the scientific publication which fulfilled
the requirements of the Journal of Ethnicity and Disease and Chapter 4, the conclusion.
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CHAPTER 2
LITERATURE REVIEW
2.1 Introduction
The following chapter provides a comparison of short and long duration exercise intervention
programs and the effect that they may have on reducing cardiometabolic disease risk. This
chapter provides an overview of the impact that physical activity may have on selected risk
factors. Different studies were used to compare the impact of aerobic training versus
resistance training as well as diet on improving fitness and reducing the risk factors
associated with non-communicable diseases (cardiovascular diseases, hypertension,
dyslipidemia and diabetes). The articles selected are not extensive but include recent
randomized-controlled trials and meta-analyses.
2.2 Anthropometry
Anthropometric parameters included in the studies cited below include height, weight, body
mass index, waist circumference, body fat percentage, subcutaneous fat, visceral fat, skinfold
thickness and body composition (Mezghanni et al. 2012; Arslan 2011). A large amount of
research has been done on anthropometric parameters including body mass index (BMI),
waist to hip ratio (WHR), waist circumference, lean body mass and body fat percentage
(subcutaneous and visceral fat) (Mezghanni et al. 2012; Saremi et al. 2010; Kerksick et al.
(2010). Anthropometric measurement is a relatively quick, easy and inexpensive method to
calculate body composition.
Multiple studies have shown that anthropometric measurements change significantly with
physical activity and diet interventions of varying mode, duration, frequency and intensity.
Table 2.1 provides an overview of 29 studies where anthropometric measurements were
monitored in response to exercise interventions. In the studies presented the sample sizes
ranged from 10 to 216 at the commencement of the intervention in the empirical studies, and
up to 8357 in the meta-analysis. The majority (27) of the studies presented in the table
included females as participants. The literature reviewed was done on aerobics related
workouts (step-aerobics, stair step counts, treadmill routines, dance, water aerobics, etc.) and
few of them with a combination of aerobics and resistance training as well as aerobics and
diet interventions. The duration of the interventions ranged from 4 weeks to 12 months with
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6-8 weeks being the most common intervention period. A meta-analysis of literature found
that exercise alone has little effect on body weight; therefore four studies on aerobic exercise
that incorporated diet were reviewed to differentiate the level of weight loss in these studies
(Cornelissen and Fagard, 2005).
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Table 2.1 Anthropometric Measurements
Study
Participants
Intervention
Significant Outcome(s)
Number
Age, mean
(SD)/range
in years
Sex
Duration
Type
Variable(s)
Mezghanni et
al. (2012)
31
25.2 (4.8)
F
12-wk, 5
sessions/wk
50-75% HRR
aerobic training
group
BMI, weight, total
fat, WC, fat free mass
A significant (p<0.01)
reduction of 3.3% in BMI,
9.5% in total fats, 8.1% in WC
Rashidlamir &
Saadatnia
(2012)
152
37.06 (5.1)
F &
M
8-wk,
4 X 50 min
sessions/wk
60-80% HRmax
aerobic training
BMI, weight, body
fat %
A significant (p<0.05)
reduction in body fat %
Arslan
(2011)
49
41.55 (6.72)
F
8-wk,
3 X 60 min
sessions/wk
Step-aerobic
dance exercise
BMI, weight, WC,
HC,WHR, four-site
skinfold thickness,
body fat %
A significant decrease
(p<0.05) in WHR, (p<0.01) in
WC, HC in (p<0.01)
Azizi
(2011)
24
29.8 (4.1)
F
8-wk,
3 X 30 min
sessions/wk
65-85% HRmax
aerobic training
BMI, weight
A significant (p=0.001)
decrease in weight and BMI
Touvra et al.
(2011)
10
55.5 (5)
F
8-wk, 4
sessions/wk
Combined
aerobic and
strength training
BMI, WC
A significant reduction in
BMI and WC
19
Behboudi et
al. (2011)
82
45-65
M
8-wk, 3 X
30-60 min
sessions/wk
60-70% HRmax
aerobic exercise
and whole body
vibration
BMI, body fat %
A significant (p=0.05) change
in BMI and 0.3% body fat %
Kwon et al.
(2011)
23
30-58
F
2-h/day and
30 min
sessions/wk
Walking step
with stair step
counts.
BMI, weight.
A significant (p<0.05)
reduction in BMI and weight
Amin-
Shokravi et al.
(2011)
40
45-55
F
12-wk, 3 X
30 min
sessions/wk
70-80% HRmax
treadmill
running exercise
BMI, weight, WHR
A significant (p<0.05)
decrease in BMI, weight and
WHR
Manzoniet al.
(2011)
212
32–57,
58–65 and
66–85
F &
M
6 X 30-45
min
sessions/wk
Cycloergometer
and walking
BMI, weight
A significant reduction in
BMI 1.6% and weight 3.6%
Saremi et al.
(2010)
25
44.3 (4.1)
M
12-wk, 5
sessions/wk
Aerobic training
BMI, WC, body fat
%, subcutaneous fat,
visceral fat and body
composition
A significant (p<0.05)
decrease in WC, body fat %,
subcutaneous fat, visceral fat
and BMI
Chaudhary et
al. (2010)
30
35-45
F
6-wk, 3
sessions/wk
60-70% HRmax
aerobic with
resistance
training
BMI, weight, body
fat %
A significant (p<0.001)
decreased in BMI and body fat
%
20
Kerksick et al.
(2010)
216
38.7 (8.0)
F
14-wk, 3
sessions/wk
Exercise and
carbohydrate,
protein diet
WC, lean, body
composition
A significant (p<0.01)
decrease WC and weight
Habibzadeh
(2010)
20
19-25
F
2-month, 3
sessions/wk
50-75% HRmax
aerobic exercise
BMI, weight, fat
mass, lean body
mass, body fat %
A significant (p=0.000)
decrease of 2.2% body fat,
2.3% BMI, 2% fat mass 1.1%
and (1.1%) lean mass
Christiansen
et al. (2010)
79
18–45
F &
M
12-wk, 3 X
60-75 min
sessions/wk
Aerobic exercise
only (EXO)
hypocaloric diet
only (DIO) and
hypocaloric diet
& exercise
(DEX)
Weight
A significant (p<0.05)
decrease of 10% in body
weight (p=0.06) (EXO),
weight loss (DIO and DEX),
14-18%hypocaloric diet
Okuneye et al.
(2010)
15
19-28
F
6-wk, 3 X
30min
sessions/wk
Aerobic dance
program
WHR
A significant (p<0.05)
reduction in WHR
Lau et al.
(2010)
18
12.45 (1.77)
F &
M
6-wk, 3 X 60
min
sessions/wk
Resistance
training
BMI, weight, WC,
HC, WHR, body
composition
A significant (p<0.00)
decrease in BMI and HC
21
van der
Heijden et al.
(2010)
*
15.3 (6.3)
F
12-wk, 2 X
30 min
sessions/wk
Aerobic exercise
BMI, body fat %,
body mass, fat mass,
lean body mass
A significant increase in lean
body mass 2–3% and body fat
1.4%
Yassine et al.
(2009)
24
65.5 (5.0)
F &
M
12-wk, 5
sessions/wk
Exercise and
moderate caloric
restriction with
control group
BMI, weight, WC,
WHR, fat mass,
visceral fat, fat free-
mass, and
Subcutaneous fat
A significant (p<0.05)
reduction in WC and WHR
Wilund et al.
(2009)
65
50-70
F &
M
6-month, 3
sessions/wk
Endurance
exercise
training.
BMI, Weight, body
fat %, intra-
abdominal fat mass,
WC, LBM
A significant (p<0.05)
reduction in weight, WC, fat
mass, visceral fat, BMI and
subcutaneous fat
Akdur et al.
(2007)
60
34 (11)
F
10-wk, 3 X
60 min
sessions/wk
60-70% HRmax
diet and step-
aerobic exercise,
diet and walking
and diet only
BMI, Fat mass, WC
and HC, body fat %,
intra-abdominal fat
mass
A significant (p<0.001)
decrease in weight of 1.3 %,
body fat of 4 %, and 7 % of
intra-abdominal fat mass
Deibert et al.
(2007)
76
43.7 (6.4)
F
12-month,
60 min
sessions/wk,
Aerobic or
endurance type
activities
Weight, WHR, fat
mass and body mass
A significant (p=0.00036)
decrease in weight and body
fat %
22
Ozcelik &
Kelestimur
(2006)
17
39.94 (2.7)
F
4-wk,
3 X 45 min
sessions/wk
Electromagnetic
ally braked
cycle ergometer
Weight,body fat%,
body mass, WHR,
LBM
A significant (p<0.001)
reduction in weight loss, 21%
fat mass, 17% WHR and 2.5%
body mass
Stewart et al.
(2005)
115
55-75
F &
M
6-month
Combined
aerobic and
resistance
training
Weight, BMI, and
body fat %
A significant (p=0.0001)
reduction in weight 4.3% and
fat mass 8.1%
Kelley &
Kelley
(2005)
*
≥18
M &
F
8-wk, 3
sessions/wk
Aerobic exercise
Weight, body fat %,
WC
A significant reduction in
body fat% 3.5% and increase
in LBM 3.5%
Cornelissen &
Fagard
(2005)
8357
21-83
F &
M
4-wk ,
7 X 60 min
sessions/wk
Aerobic
endurance
training
Weight, body fat %
WC and
subcutaneous fat
A significant decrease of 2%
in weight , 1.4% in WC and
body fat %
Irwin
(2003)
173
50-75
F &
M
12-month, 5
sessions/wk
Moderate-
intensity
exercise
Weight, body fat %,
LBM, WC, visceral
fat, subcutaneous fat
A significant (p<0.001)
decrease of weight, 2.3% WC
and 7% body fat %
Park et al.
(2003)
30
40-45
F
24-wk,
3 X 60 min
sessions/wk
Aerobic training
group, combined
training group
BMI, weight,
abdominal fat,
visceral fatand
percent body fat %
A significant (p<0.05)
reduction in 6.1% weight and
4.2% body fat %
23
Nieman et al.
(2002)
102
25-75
F
12-wk,
5 X 45 min
sessions/wk
60-65%, 70-
80% MHR step
exercise only,
exercise and
diet, or diet only
Weight, body
composition, body
fat%, abdominal fat
and visceral fat
A significant decrease in
Weight by 8.3%, body fat %
by 9.2%, abdominal fat by
18% and visceral fat by 48%
Andersen et
al. (1999)
40
21-60
F
16-wk, 60
min
Aerobic exercise
with low fat diet
BMI, weight, body
fat %
A significant (p<0.001)
reduction in BMI, weight and
body fat %
Wk-week(s)./-per, F-female. M-male, h-hour, min-minutes. WHR-waist hip ratio. BMI-body mass index. LBM-Lean body mass. * number of
participants who are not mentioned. WC-waist circumference.
24
The most effective programs for weight loss as observed in the various studies were between
8-16 weeks, combined aerobic and resistance exercise, 3 times per week with caloric
restriction (Arslan, 2011; Touvra et al 2011). A study by Park et al. (2003) established that
the subcutaneous fat and visceral fat were decreased through a combination of resistance and
aerobic training rather than only aerobic training. In a randomised controlled 12-week study
of a group of 91 moderately obese women, a combination of diet and exercise training
significantly lowered body mass index, percent body fat, total cholesterol and triacylglycerol
(Nieman et al., 2002). The American College of Sport Medicine (2010) proposes that up to
60 min/day (>250min/week) may be required when relying on exercise alone for weight loss.
Although different studies have investigated low, moderate and high intensity exercise in the
management of weight loss in obese individuals, it is evident that most of these studies
emphasised using moderate intensity exercise for weight loss. Some studies suggest that a
well-structured aerobic exercise intervention should perhaps range between >30-40%
VO2maxor 50-70%HRmax (Behboudi et al., 2011; Mezghanni et al., 2012). Short term high
intensity aerobic exercise (85% HRmax) may bring additional health benefits but may not
necessarily induce weight loss (Azizi, 2011). Although other studies suggested training 3
times per week (Arslan,2011) has shown that an effective frequency for moderate-intensity
aerobic activity is 5 times per week (Yassine et al.,2009;Mezghanni et al., 2012). Vigorous
activity can be separated into shorter bouts of 10 minute intervals with the aim of
accumulating 60 minutes in total (American College of Sport Medicine, 2010).
While aerobic exercise remains a common modality used to lower some anthropometric
values, there has been no evidence from randomised controlled trials investigating weight
loss by resistance training. A short term study by Lau et al.(2010), showed a significant
25
(p<0.01) increase with a small effect size (0.2) in waist-hip circumference, fat-free mass and
an increase loss of fat mass all of which was associated with a reduction in health associated
risks. Saremi et al.(2010), observed reductions in abdominal obesity with a 12 week, 5days
per week intervention and this is consistent with Arslan (2011) who reported that obese
participants who performed an 8-week, 1 hour per day, 3 days per week step-aerobic dance
exercise program showed a marked reduction in body composition (WHR, WC, weight, BMI,
fat percentage and lean body mass). Similar results were found for a long term study of 24
weeks, 3 times per week,60 minutes/ day where significant (p<0.05) reductions in body
weight and a reduction (4.2%) of total body fatwere reported (Park et al., 2003).
In summary, there is substantial evidence that regular aerobic exercises can effectively alter
body composition in both men and women. Physical activity may increase total FFM, and
reduce weight and percentage body fat. Whilst exercise is clearly effective in improving a
person‟s body composition profile, the evidence is also clear that a combination of exercise
and caloric restriction is more effective.
2.3 Lipoproteins
Lipoproteins consist of total cholesterol, triglycerides, low density lipoproteins („bad‟
cholesterol) and high density lipoproteins (good cholesterol). There are numerous studies that
have been conducted looking at the effects that exercise may have on lipoproteins
(Mezghanni et al. 2012; Khademi et al. 2011). In table 2, the author has summarized 30
studies, the majority of which are based on aerobics related interventions (treadmill running,
stationary bike, Korean dance, water aerobics, etc). Five of the articles included a comparison
of aerobic versus resistance training. Two studies on aerobic training combined with dietary
intervention were included as a combination of diet and exercise is advocated as the best non
26
pharmacological method for reducing blood lipoproteins (Akdur et al., 2007;Yassine et al.,
2009).
Most studies reported in the table below consist of female participants with interventions
ranging from 1 month to 24 months (Khademi et al. 2011; Chaudhary et al. 2010). The
literature search was done using recently published articles found in “Science Direct”,
“Pubmed” and “Google Scholar” from 1999 until 2012. Multiple studies including meta-
analyses of randomised-controlled trials and recently published articles were searched to
provide a concise summary of the available evidence. Most studies recommended that
aerobic exercise and lipoprotein reduction is the primary treatment goal for CVD risk
reduction. Physical activity and weight management should be implemented in those
individuals with the MetS, with the aim of treating elevated triglycerides and low HDL-C.
Although aerobic exercise training has generally been shown to increase HDL-C and to
decrease triglycerides, results are mixed particularly for that of LDL-C.
27
Table 2.2 Lipoproteins
Study
Participants
Intervention
Significant Outcome
Number
Age, Mean
(SD)/range
in years
Sex
Duration
Intensity
Variable(s)
Mezghanni et
al. (2012)
31
25.2 (4.8)
F
12-wk, 5
sessions/wk
50%-75% HRR
aerobic intensity
training group
TG, HDL-C,
LDL-C
A significant (p<0.001)
reduction in LDL-C by 16.5%
Khademi et al.
(2011)
20
15-65
M
8-wk,
3 X 45 min
sessions/wk
60-79% HRmax
aerobic exercise
LDL, LDL/TC,
TC,TG and HDL
A significant (p<0.05)
reduction of LDL/TC and TG
Seo et al.
(2011)
20
40
F
12-wk, 3
sessions/wk
60-70% HRmax
combined
resistance and
aerobic exercise
training program
TG, HDL
A significant (p<0.05)
decrease in TG and increase
in HDL-C
Chaudhary et
al. (2010)
30
35-45
F
6-wk, 3
sessions/wk
60-70% HRmax
resistance and
aerobic training
TC,TG, HDL,
LHL
A significant (p<0.001)
decrease of LDL-C and
increase in HDL-C
Saremi et al.
(2010)
25
44.3 (4.1)
M
12-wk, 5
sessions/wk
Aerobic training
TC,TG, LDLC
A significant (p<0.05)
decrease in TG, TC & LDL-C
28
Amin-Shokravi
et al. (2010)
40
45-55
F
12-wk,
3 X 30 min
sessions/wk
70-80% HRmax
treadmill running
exercise
HDL-C, TC and
lipoprotein
A significant (p<0.001)
decrease in TC and increase
HDL-C
Habibzadeh et
al. (2010)
20
19-25
F
2-month, 3
sessions/wk
50-75% HRmax
exercise
TC, TG
A significant (p<0.05)
decrease in TC and TG
Miyashita et al.
(2010)
10
46 (2)
M
30 min
sessions/wk
60% HRmax
moderate-
intensity exercise
TG
A significant (p<0.05)
decrease in TG by 9%
Akçakoyun
(2010)
100
40-45
M
8-wk,
3 X 55 min
sessions/wk
Exercise
TC, TG, LDL,
HDL
A significant (p<0.001)
decrease TG and increase in
HDL-C of (p<0.01)
Adamo et al.
(2010)
30
12-17
F & M
10-wk,
2 X 60 min
sessions/wk
80-100% HRmax
experimental
group with
stationary bike
music vs video
TC,TG, LDL,
HDL
A significant reduction in TC
by 7%
Christos et al.
(2009)
20
55 (5.2)
F
16-wk, 4
sessions/wk
Resistance and
aerobics exercise
training
TC,TG, LDL,
HDL
A significant (p<0.001)
reduction in TG by 18.9% &
decrease in HDL-C by 17.2%
Yassine et al.
(2009)
24
65.5 (5.0)
F & M
12-wk, 5
sessions/wk
Exercise group
and EX + CR
TC, TG,LDL,
HDL
A significant (p<0.05)
decrease in TC, LDL-C & TG
29
Wilund et al.
(2009)
65
50-70
F & M
6-month, 3
sessions/wk
Endurance
exercise training
TC, TG, LDL-C,
HDL-C
A significant (p<0.05)
decrease in TC and LDL-C
and increase in HDL-C
Mitchell et al.
(2008)
10
18-25
F
3 X 60 min
sessions/wk
Exercise group
TG
A significant (p=0.006)
reduction in TG level
Kim et al.
(2007)
64
65-90
F
10-wk, 4
sessions/wk
Korean dance
exercise
TC, TG, LDL-C,
HDL-C, HDL-
C/HDL-C
A significant (p<0.001)
decrease in LDL-C, LDL-C
/HDL-C and increase HDL-C
Akdur et al.
(2007)
60
34 (11)
F
10-wk,
2 X 60 min
sessions/wk
Diet and
step-aerobic
exercise, or diet
and walking, or
diet only
TC,
TG, HDL and
LDL
A significant (p<0.05)
decrease in TC and LDL-C
Kelley &
Kelley (2007)
220
≥18 years
F & M
8-wk, 3
sessions/wk
Aerobic exercise
TC, TG,HDL-C,
LDL-C and
TC/HDL-C
A significant reduction of 5%
in LDL-C, 6% in TC/HDL-C
and 5% in TG
Varady et al.
(2007)
84
40-70
F
8-wk, 3
sessions/wk
Combination of
exercise and
plant sterols
TC, LDL-C,
HDL-C
A significant (p<0.01)
decrease in TC by 7.7%,
LDL-C, TG by 11.8% and
increase in HDL-C by 7.5%
30
Deibert et al.
(2007)
76
43.7 (6.4)
F
12-month,
2 X 60 min
sessions/wk
Aerobic or
endurance type
activities
TC, TG, LDL-C,
HDL-C
A significant (p<0.01)
reduction in TC, in LDL-C,
TC and increase in HDL-C
Kelley et al.
(2006)
1,260
≥18 years
F & M
≥4-wk
Aerobic exercise
TC, TG, LDL-C,
and HDL-C
A significant increase in
HDL-C by 9% and a decrease
of 11% in TG
Kelley &
Kelley (2006)
984
≥18 years
F & M
≥8wk
Aerobic exercise
HDL3-C, HDL2-
C, HDL-C
A significant increase in
HDL2-C by 11%
Cornelissen &
Fagard (2005)
8357
21-83
F &M
4-wk, 7 X
15-63 min
sessions/wk
Aerobic
endurance
training
TG, LDL, HDL
A significant (p<005)
increase in HDL–C and
decrease in TG
Varady &
Jones (2005)
40
21-60
F &M
16-wk, 3–7
X 30-60min
sessions/wk
Diet and
exercise
TC, TG, LDL-C
and HDL-C
A significant decrease 7–18%
in TC, 7–15% in LDL-C, and
4–18% in TG and increase in
HDL-C levels by 2–8%
Bhalodkar et
al. (2005)
388
49 (10.5)
F & M
3-5 X 128-
152 min
sessions/wk
Exercise group
LDL, HDL
A significant increase in
HDL-C by11%
31
Kelley et al.
(2004)
*
≥18
F
8-wk
Aerobic exercise
HDL-C, TC,
LDL-C, and TG
A significant increase of 3%
in HDL-C and decrease of 2%
in TC, 3% in LDL-C, and 5%
in TG
Park et al.
(2003)
30
40-45
F
24-wk,
3 X 60 min
sessions/wk
Aerobic training
group with
combined
training group
TC, TG,LDL-C,
HDL-C,
Apolipoprotein
A-I and
ApolipoproteinB
A significant (p<0.05)
decrease TC, LDL-C, TG and
Apolipoprotein B and
increase in HDL-C
Nieman et al.
(2002)
102
25-75
F
12-wk,
45-60 min
sessions/wk
60-65%, 70-80%
MHR step
exercise only,
exercise and diet
or diet only
TC, TG, LDL-C
and HDL-C
A significant (p<0.001)
decrease in TC, LDL-C, TG
and increase in HDL-C
Andersen et al.
(1999)
40
21-60
F
1 to 6-wk,
60 min
sessions/wk
Aerobic exercise
with low fat diet
TC, TG, LDL-C
and HDL-C
A significant (p<0.05)
reduction in TC by 10.1% and
TG by 16.3%
Wk-week(s)./-per, d-day(s).h-hour. min-minutes, x-times.* number of participants who are not mentioned, HDL2-C, high density lipoprotein
two cholesterol.TC-Total-cholesterol (mg/dl).LDL-C-Low density lipoprotein Cholesterol (mg/dl).HDL-C-High density lipoprotein-Cholesterol
(mg/dl).TG-Triglyceride (mg/dl). Exercise combined with caloric restriction (EX + CR).
32
It has been suggested that aerobic exercises between 150 and 250 min/week, 30 min/day may
improve cardio-respiratory fitness and reduce triglycerides (p=0.05), total cholesterol
(p=0.04) and low density lipoproteins (p=0.05) (Saremi et al., 2010). According to Arslan
(2011), an appropriate training program includes vigorous exercise training sessions 3 days
per week while, Yassine et al. (2009) and Mezghanni et al (2012) suggest that a suitable
frequency for moderate-intensity aerobic activity is 5 times per week. According to
Mezghanni et al. (2012), moderate intensity exercise greater than (50%-75% HRR, 5days per
week) is required to prevent weight gain and manage cholesterol levels. In that study a
significant (p=0.001) reduction in low density lipoprotein (-16.5%) was seen in both exercise
and diet groups. Equally, some studies suggest that the optimal intensity of a well-structured
exercise aerobic program should range between >30-40 VO2max or 60-79HRmax to maximise
health benefits (Chaudhary et al., 2010; Khademi et al., 2011). A meta-analyses of short term
high intensity aerobic exercise (4 weeks) bouts may bring additional health benefits and a
significantly increase HDL-C by 9% and decrease triglycerides by 11%.
A short term study by Cornelissen & Fagard (2005) found a significant (p<0.05) increase in
high density lipoprotein with a significant decrease in triglycerides. Along term study lasting
16 weeks, with training sessions 3-7 times per week for 60 minutes resulted in a significant
reduction in all the cholesterol values total cholesterol (7–18%), low density lipoprotein
cholesterol (7–15%), and triglycerides (4–18%). Another study by Park et al. (2003), which
lasted 24 weeks, with training sessions 3 times per week for 60 minutes, combined aerobic
and resistance training resulted in a significant decrease in TC, LDL-C, TG and an increase in
HDL-C. It has also been suggested that short term interventions also show some statistically
significant change in LDL and total cholesterol (Akdur et al., 2007). Longer term
33
interventions (16 weeks 60 minutes per day) have resulted in significant reductions in total
cholesterol (10.1%) and triglycerides by (16.3%) (Andersen et al., 1999). It is recommended
that therapeutic lifestyle changes (e.g., physical activity, weight management and dietary
intervention) should be implemented in those individuals with the Metabolic Syndrome with
the aim of treating elevated triglycerides, LDL-C, decreased HDL-C. Generally, aerobic
exercise training increases HDL-C and decrease triglycerides and LDL-C(Cornier et al.,
2008).
In summary, the beneficial effects of exercise training on lipids and lipoproteins are routinely
observed and may have additional impact when combined with dietary modification and
weight loss. Some studies suggest that a combination of resistance and aerobic training
(moderate to high intensity) increases HDL-C, decreases TG, TC, LDL-C as well as
improving cardiovascular function, in both male and female diabetics. Further research is
required to investigate the combination of aerobic and resistance training of varying
intensities, and the duration to treat patients with cardiometabolic.
2.4 Glucose
Impaired glucose tolerance form physical activity is potent regulator of blood glucose levels
and chronically elevated blood glucose and associated impaired glucose tolerance is
associated with a high prevalence of coronary heart disease (Tokmakidis et al., 2004). High
glucose concentration causes cardiovascular disease, hyperglycemia and eye disease as well
as accelerating atherosclerosis (Seo et al., 2011). Blood glucose decreases after physical
training depending on various intensities or from different durations of training.
The effect of exercise on glucose has been investigated by many researchers on different
types of exercise i.e swimming, running, cycling etc. Table 2.3 provides an overview of 25
34
studies investigating the effects of aerobic exercise, combined aerobics and resistance as well
as exercise and diet on glucose levels. 19 of the studies employed aerobic interventionsof
moderate intensity over a long period of time and clarifying mechanisms by which physical
training enhances blood glucose; 6 looked at the efficacy of resistance training and 3are
combined exercise and diet intervention.
35
Table 2.3 Glucose
Study
Participants
Intervention
Significant Outcome
Number
Age, Mean
(SD)/range
in years
Sex
Duration
Intensity
Variable
Valizadeh et al.
(2012)
25
35-50
M
8-wk, 3
sessions/wk
50-60% HRmax aerobic
exercise group
Glucose
A significant (p<0.05) reduction
in glucose
Short et al.
(2012)
18
13-27
F & M
45-min
Aerobic exercise
Glucose
A significant reduction of 6% in
glucose level
Behboudi et al.
(2011)
82
45-65
M
8-wk, 3 X
30-60 min
sessions/wk
60-70% HRmax aerobic
exercise and whole body
vibration
Fasting
glucose
A significant (p<0.05) decrease
in fasting glucose
Seo et al.
(2011)
20
40
F
12-wk, 3
sessions/wk
60-70% combined
resistance and aerobic
exercise training
Glucose
A significant decrease in
Glucose level
Sushma et al.
(2011)
35-65
84
F & M
1-3months
aerobic exercise
(walking)
Glucose
A significant decrease in
Glucose level
Touvra et al.
(2011)
10
55.5 (5)
F
8-wk, 4
sessions/wk
Combined aerobic and
strength training
Glucose
A significant decrease (11.8%)
in glucose
Hazley et al.
(2010)
12
53 (9)
55 (9)
F
8-wk
Resistance training
Glucose
A significant (p<0.05) decrease
in glucose
36
Saremi et al.
(2010)
25
44.3 (4.1)
M
12-wk 5
sessions/wk
Obese group Aerobic
training
Fasting
glucose
A significant (p=0.01) decrease
in fasting glucose
Christiansen et al.
(2010)
79
18-45
F & M
12-wk, 3 X
60–75 min
sessions/wk
Aerobic exercise only,
hypocaloric diet only, or
hypocaloric diet and
exercise
Glucose
A significant (p<0.05) decrease
in fasting glucose EXO by 10%,
DIO + DEX by 14-18%
Lau et al.
(2010)
18
12.45 (1.77)
F & M
6-wk,
3 X 60 min
sessions/wk
Resistance training
Glucose
A significant (p<0.001) decrease
in glucose
Solomon et al.
(2010)
22
66 (1.0)
F & M
12-wk,
5 X 60 min
session/wk
85% HRmax exercise
training intervention
Glucose
A significant (p<0.05) reduction
in glucose level
Christos et al.
(2009)
20
55 (5.2)
F
16-wk, 4
sessions/wk
Resistance and aerobics
exercise
Glucose
A significant (p<0.001) decrease
in fasting glucose by 5.4%
Bweir et al.
(2009)
23
45-65
F
10-wk
Resistance exercise
training
Glucose
A significant (p<0.001)
reduction in glucose
Yassine et al.
(2009)
24
65.5 (5.0)
F & M
12-wk, 5
sessions/wk
Exercise group or
exercise + moderate
caloric restriction
Glucose
A significant (p<0.001) decrease
in glucose in both groups
Tresierras &
Balady (2009)
56
45 (6.1)
F & M
45 min
sessions/wk
Resistance exercise
training
Glucose
A significant (p<0.001) decrease
in glucose
37
Wilund et al.
(2009)
65
50-70
F & M
6-month,
3 X 60 min
sessions/wk
Endurance exercise
training
Glucose
A significant (p<0.05) decrease
in glucoseby 10%
Mitchell et al.
(2008)
10
18-25
F
3
sessions/wk
Exercise group
Glucose
A significant (p=0.016) decrease
in glucose levels
Deibert et al.
(2007)
76
43.7 (6.4)
F
12-month,
2 X 60 min
sessions/wk
Aerobic and endurance
activities
Glucose
A significant (p<0.01) decrease
in fasting glucose levels by ~ 10
%
Kreider (2007)
40
25.2 (4.8)
F & M
1 yr
Resistance training
Glucose
A significant (p<0.01) reduction
in glucose
Snowling &
Hopkins (2006)
1003
55±7
F & M
5-104 wks
Combined aerobic and
resistance training
Glucose
A significant (p<0.01) reduction
in glucose
Cornelissen &
Fagard (2005)
8357
21-83
F & M
4-wk, 7 X
15-63 min
sessions/wk
Aerobic endurance
training vs control
groups
Glucose
A significant (p<0.001) decrease
in glucose
Boule et al.
(2005)
596
40-65
F & M
20-wk, 30
min/day
55-75% VO2max
endurance training
Glucose
A significant (p<0.02) decrease
in glucose by 3%
Nieman et al.
(2002)
102
25-75
F
12-wk, 5 X
45-60 min
sessions/wk
60-65%, 70-80% MHR
step exercise only, diet
and exercise or diet only
Glucose
A significant (p<0.001) decrease
in glucose
W-week(s), /(per), d-(day)(s), h-(hour), min-(minutes). EXO-(exercise only).DIO + DEX- (diet and exercise), DIO-(diet only).
38
Several studies have supported the notion that losing between 5-10% of total body weight
may help delay the onset of diabetes in pre-diabetic patients (Behboudi et al. 2011; Sushma et
al. 2011). Valizadeh et al. (2012) reported that a relatively short term intervention (aerobic
exercise at 50 – 60%HRmax) of 8 weeks was effective in decreasing blood concentration. It
has also been reported that after 12 weeks training, 5 days per week at 60-85% of MHR, a
significant decrease in fasting glucose can be expected (Saremi et al. 2010). Behboudi et al.
(2011) reported a significant decrease in fasting glucose after 8 weeks of aerobic exercise
training 3 times a week compared with individuals using all body vibration techniques and
the control group (p=0.02). Lau et al. (2010) reported that 1 hour sessions of resistance
training performed three times a week on alternate days, for 6 weeks significantly reduced
fasting glucose (p<0.001) in obese adolescents. Christiansen et al. (2010) found that a 12
week, 3 times per week (60-75% HRmax) aerobic exercise program decreased fasting glucose
in hypo-caloric diet and exercise(14-18% p=0.05) versus hypocaloric diet(diet only p<0.05).
This is in agreement with Yassine et al. (2009) who investigated a 12 week, 5 day per week
exercise program (-6.8 ±2.7kg) compared with more effective program of individuals
performing exercise in conjunction with a moderate caloric restricted diet (-500kcal, EX+CR)
(-3.7 ±3.4kg). Meta-analyses involving 439 studies and 3936 participants showed a
significant decrease in blood glucose after4 weeks of exercising 7 sessions per week between
15-63 minutes per session Cornelissen & Fagard, (2005).
A study by O'Leary et al. (2006) found that a 4.9% reduction in fasting blood glucose is
associated with a 4.7% reduction in obesity, type 2 diabetes, and cardiovascular disease. A
minimum of 60 minutes, but optimally 80-90 minutes of moderate intensity physical activity
per day may be needed to limit weight gain and to prevent or treat cardiovascular diseases in
overweight or obese individuals.
39
Research has suggested that a substantial part of the favourable changes that exercise elicits
on glucose metabolism may be attributed to the effects of the most recent exercise session.
Several studies have shown that exercise for longer than 50 min at ∼70–75% of maximum
heart rate reserve (MHRR) for 7 consecutive days can improve insulin sensitivity and glucose
tolerance by as much as 35% in obese and glucose-intolerant individuals (Lakka & Bouchard
2005; Behboudi et al., 2011).
It is clear that combined aerobic and resistance exercise improves glucose homeostasis by
enhancing glucose transport and insulin action in working skeletal muscle (Cornier et al.,
2008). The muscle contractions stimulate uptake of glucose through non-insulin-dependent
mechanisms during exercise, but sensitivity to insulin-mediated glucose uptake is greatly
improved immediately after exercise (Saremi et al. 2010). Although a session of aerobic
training is not effective in improving glucose tolerance in an insulin-resistant individual with
type 2 diabetes, glucose uptake during exercise is increased, and glucose and insulin response
to a meal immediately after exercise is improved (Cornier et al., 2008). Interestingly, Cornier
et al. (2008) mentioned that frequent exercise are accompanied by improvements in
cardiorespiratory fitness (i.e., aerobic exercise training), nevertheless no change in body
weight, do not appear to improve insulin-mediated glucose uptake beyond the effect of the
last bout of exercise. In order to gain continued benefits of exercise on insulin action, an
individual would need to follow the ACSM recommendation to exercise at least 30 minutes
in most days of the week. There is evidence to suggest that aerobic exercise training may
need to be accompanied by weight loss for a persistent effect on glucose tolerance and insulin
action beyond the immediate post-exercise effects (Seremi et al. 2010).
Christiansen et al. (2010) reported that the combination of diet and exercise induce weight
loss while diet elicits reduce blood glucose. These data suggest that a high-diet appears to
40
exacerbate weight, when combined with exercise, may delay the onset of T2D in the risk of
individuals, but only a low-diet treatment method prevents diabetic onset.
A total number of 8357 in a meta-analyses study of non- diabetic individuals found a
significant decrease in glucose after aerobic endurance training (Cornelissen & Fagard,
2005). The effectiveness of aerobic training in reducing cardiovascular risk depends on many
variables including age, sex, race, cardiovascular history, current risk levels, and the type of
training regimen employed. There is also substantial evidence that aerobics, resistance, and
combined exercise training can moderately and effectively alter glucose levels which are
related risk factors for diabetes in both men and women (Sushma et al., 2011).
2.5 Blood Pressure
Elevated blood pressure (BP),or hypertension is one risk factor that contributes towards the
development of cardiometabolic disease. In South Africa, it is estimated that 55% of the
population are hypertensive and it has been documented that the prevalence thereof is higher
in Black Africans (Steyn et al., 2001).In the literature reviewed, there is generally consensus
that aerobic training elicits significant reductions in BP. It is well documented that in
hypertensive individual‟s exercise induces a reduction in systolic blood pressure of
approximately 7.4mmHg and 5.8mmHg in diastolic pressure whilst this may seem like a
small reduction it is clinically relevant (Delavar and Faraji, 2011). Table 2.4 provides an
overview of20 studies investigating the effect of exercise interventions on blood pressure.
These studies include different aerobic interventions such as water aerobics, treadmill
running and few have been included on resistance training and dietary interventions to
investigate the combined effect of the training modalities in reducing blood pressure. The
duration of the interventions ranged from 4-52 weeks.
41
Table 2.4 Blood pressure
Study
Participants
Intervention
Significant Outcome
Number
Age, Mean
(SD)/range
in years
Sex
Duration
Intensity
Variable(s)
Khademi et al.
(2011)
20
15-65
M
8-wk, 3 X 45
min
sessions/wk
60-79% HRmax
aerobic exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.000)
reduction of SBP and DBP
Delavar & Faraji
(2011)
10
37.6 (6.5)
F
3-7 X 2-h
sessions/wk
60% HRmax
resistance exercise
with endurance
exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.05)
reduction of SBP and DBP
Seo et al.
(2011)
20
40
F
3 sessions/wk
60-70% HRmax
resistance
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in post-DBP
Chaudhary et al.
(2010)
30
35-45
F
6-wk, 3
sessions/wk
60-70% HRmax
resistance with
aerobic
training
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in post-DBP
Farahani et al.
(2010)
40
48.3 (10.74)
M
10-wk,
3 X 55 min
sessions/wk
Water Aerobic
Exercise
SBP (mmHg),
DBP (mmHg),
mean BP
A significant (p<0.001)
reduction in DBP and mean
arterial pressure (p=0.016)
42
Saremi et al.
(2010)
25
44.3 (4.1)
M
12-wk 5
sessions/wk
Aerobic training
SBP (mmHg),
DBP (mmHg)
A significant (p<0.05)
decrease in SBP
Amin-Shokravi et
al. (2011)
40
45-55
F
12-wk, 3
sessions/wk
70-80% HRmax
treadmill running
exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
decrease in SBP and DBP
Piotrowska-Całka
(2010)
19
30-62
F
24-wk,
2 X 45 min
sessions/wk
Moderate intensity
deep water aerobics
SBP (mmHg),
DBP (mmHg)
A significant (p<0.05)
reduction in SBP
Christos et al.
(2009)
20
55.0 (5.2)
F
16-wk, 4
sessions/wk
Resistance and
aerobics exercise
training
BP
A significant (p<0.01)
reduction in BP
Yassine et al.
(2009)
24
65.5 (5.0)
F &
M
12-wk, 5 X
50-60 min
sessions/wk
60-85% HRmax 70%
VO2max EX with
EX + CR
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in SBP and DBP
Wilund et al.
(2009)
65
50-70
F &
M
6-month, 3
sessions/wk
Endurance exercise
training
SBP (mmHg),
DBP (mmHg)
A significant (p<0.05)
decrease in SBP and DBP
Rodriguez et al.
(2008)
30
19.6 (0.7)
76.0 (2.7)
M
6-month, 3
sessions/wk
70% of 1RM MS &
TRI non-exercise
SBP (mmHg),
DBP (mmHg),
mean BP
A significant (p<0.05)
reduction in mean BP
Pantelićet al.
(2007)
59
22-25
F
3-month,
3 X 60 min
sessions/wk
60-75% HRmax
aerobic exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.01)
decrease in SBP and in
DBP
43
Deibert et al.
(2007)
76
43.7 (6.4)
F
12-month,
2 X 60 min
sessions/wk
Aerobic or
endurance type
activities
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
decrease in SBP
Stewart et al.
(2005)
115
55-75
F &
M
6-month, 3
sessions/wk
Combined aerobic
and resistance
training
SBP (mmHg),
DBP (mmHg)
A significant decrease in
SBP and DBP
Cornelissen &
Fagard (2005)
8357
21-83
F &
M
4-wk,
7 X 63 min
sessions/wk
Endurance training
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in SBP and DBP
Fagard (2005)
2674
21-79
F &
M
4-52-wk, 1-7
X 15-70 min
sessions/wk
30-80% HRmax
aerobics training,
diet and exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.01)
reduction of in SBP and
DBP
Fagard (2001)
2674
21-79
F &
M
4-52-wk, 3-5
X 30-60 min
sessions/wk
45-85% HRmax
aerobic/endurance
exercise
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in SBP and DBP
Andersen et al.
(1999)
40
21-60
F
16-wk,
60 min
sessions
Aerobic exercise
with low fat diet
SBP (mmHg),
DBP (mmHg)
A significant (p<0.001)
reduction in SBP
Multiple set group (MS); and a tri-set group (TRI). Resistance before endurance exercise (RBE).exercise EX; caloric restriction CR, Minutes
(Min); A tri-set group (TRI). Systolic blood pressure (SBP) and Diastolic blood pressure (DBP); HRmax; maximam heart rate; Day per week
(d/wk
44
Meta-analyses of randomized, controlled trial studies on the effect of aerobic exercise on
blood pressure suggested that exercise reduces systolic and diastolic blood pressure by
approximately 3.8 and 2.6 mm Hg, respectively. It provided strong evidence that although the
effect of aerobic exercise on blood pressure was small, there may be added benefit when
combined with dietary modification.
Studies have shown that aerobic exercise of 20-60 minutes, 3-5 days per week at 50-70%
maximum heart rate (HRmax) can be used to reduce blood pressure (Amin-Shokravi et al.,
2010; Khademi et al., 2011). Anaerobic exercise is the most effective exercise modality in the
prevention and treatment of hypertension (Saremi et al., 2010). Saremi et al.(2010) have
reported that moderate intensity exercise (60-70% HRmax) may result in greater decreases in
resting blood pressure than exercise of a higher intensity. Research studies conducted using
resistance training reveal inconsistent results (Saremi et al., 2010). For example, no
significant (p>0.05) reduction in blood pressure was seen after 3 sets of 10 repetitions of
resistance exercise performed at different intensities (40, 60, and 80% of 1RM) within a time
period of 120 minutes post-exercise (Rodriguezet al., 2008). However, it was also stated that
no significant differences were found between multiple sets and tri-set groups compared with
the control group while mean blood pressure significantly reduced (p<0.05) after 6 months of
exercising 3times per week. Although resistance training showed a significant (p<0.001)
change in post diastolic blood pressure, it has been established that it is not the preferred
mode of exercise in the prevention and treatment of hypertension although it can be
incorporated into an exercise program that uses low resistance and high repetitions
(Chaudhary et al. 2010).Fagard (2005) have performed a meta-analysis of 44 randomised
controlled interventions in which 1738 health sedentary women aged 21-79 years undertook
45
an exercise intervention lasting between 7 to 52 weeks, 15-70 minutes per session at
intensities between 30-80% HRmax. The results indicate that sessions of five to seven times
per week produced a greater reduction in blood pressure whereas three sessions per week
have been considered to have a minimal effect for blood pressure reduction. It is debatable
whether duration longer than 30 minutes produces a greater reduction in blood pressure.
Evidence has revealed that high intensity exercise (85% HRmax) was as effective as low
intensity (<60HRmax) in reducing elevated blood pressure (Yassine et al. 2009). Regular
aerobic exercise at 40-70% of VO2R, 3-7 days per week, 30 to 60 minutes showed a 5 to 7
mmHg reduction in blood pressure (Fagard, 2001).
Aerobic exercise of short and long duration, low- to moderate-intensity was found to lower
BP. The duration of the blood pressure reduction persists up to 24 h after exercise (Deibert et
al., 2007) and daily exercise is required. The effects of exercise have been found to be more
consistent with DBP. Farahani et al., (2010) reported that a 10week water aerobics training
program of 55 minutes, 3days per week on alternate days was as effective in lowering SBP.
A meta-analysis encompassing 2674 persons revealed that a decrease in systolic blood
pressure of just 2mmHg will reduce death from stroke by 10% and death from ischemic heart
disease by 7% among middle-aged persons (Fagard, 2005). These calculations are in
accordance with older analyses (Fagard 2001; Andersen et al., 1999).
In conclusion adopting a healthy lifestyle including physical activity is critical in preventing
high BP and is an indispensable part of the treatment of those with hypertension. Evidence
from the above studies shows that aerobic endurance training elicits small but significant
reductions in BP (Delavar and Faraji, 2011) and this in turn will reduce the risk of
cardiometabolic disease.
46
CHAPTER 3
SCIENTIFIC PUBLICATION
Title of paper
A 10-week aerobic exercise program reduces cardiometabolic disease risk in
overweight/obese female African university students.
Accepted for publication in the Journal of Ethnicity and Disease (see Appendix D)
Authors
Musa Lewis Mathunjwa BSc Hons1, Stuart John SemplePhD1,Corrie du Preez PhD 2
1Department of Biokinetics& Sports Science, 2Department of Consumer Sciences, University
of Zululand, South Africa
47
Abstract
Objectives: The prevalence of obesity and associated cardiometabolic disease (CMD) is
increasing among black African women and requires urgent attention in the form of
preventative strategies. To date, there is limited scientific evidence highlighting the efficacy
of Tae-bo as an intervention for reducing weight and CMD risk factors.
Design: Prospective experimental.
Setting: South Africa, University of Zululand
Participants: Sixty previously sedentary participants [25 ± 5 y] who were overweight (BMI
> 25 - 29.9 kg.m-2) or obese (BMI ≥ 30 – 39.9 kg.m-2).
Intervention: Participants performed a 10-week aerobic (Tae-bo) program 60 min/day for
three days a week at moderate intensity for the first five weeks and high intensity for the last
five weeks.
Main Outcome Measures: Anthropometric parameters (height, weight, waist and hip
circumference and sum of skinfolds), blood pressure, fasting glucose, and lipoproteins were
measured at baseline, after six weeks and 24 hours after completion of the 10-week program.
Data was analysed using repeated measures ANOVA and a Tukey Post hoc test.
Results: The prevalence of metabolic syndrome was 26.7% pre-intervention and decreased to
16.3% post intervention. There was a statistically significant (p ≤ 0.05) improvement in
weight, BMI, waist and hip circumference, glucose, triglycerides, total cholesterol, LDL-C,
HDL-C, resting heart rate and resting systolic and diastolic blood pressures following the
intervention.
48
Conclusion: A 10-week 30 session Tae-bo exercise program was effective in reducing
traditional risk factors associated with cardiometabolic disease in overweight/obese
university students.
KEY WORDS: Aerobic, cardiometabolic disease, obesity
49
Introduction
It is well established that being overweight or obese increases the risk of developing
cardiometabolic related diseases such as coronary artery disease, type 2 diabetes and
hypertension.1
Research in South Africa indicates that 56.6% of the female population is overweight, 32.2%
are obese and 4.8% are morbidly obese (BMI ≥ 40.0 kg.m-2).2 This is a significant health
concern due to the increase in morbidity and mortality associated with being overweight.
Data from the Behavioural Risk Factor Surveillance System revealed that the African
population in South Africa, particularly women, shows an increased risk of being overweight
and obese compared with other racial groups3 and in some instances the prevalence of obesity
is greater in females compared with males living in the same geographical location.4
A major factor contributing to the obesity epidemic is physical inactivity.5 According to
World Health Organisation6 an unhealthy lifestyle may lead to obesity, high blood pressure
and diabetes. Poor aerobic fitness levels are associated with cardiometabolic disease (CMD)
risk factors such as large waist circumferences, hypertension and elevated insulin and blood
glucose and lipid levels.4,7 The trend of low physical activity amongst African South African
women has recently been highlighted and research confirms that approximately 48% of the
female follow a sedentary livestyle.8There is also evidence indicating that obese African
females are more likely to suffer from hypertension, increased vascular resistance and
metabolic syndrome compared to their Caucasian counterparts. 9,10
Tae-bo stands for Total Awareness Excellence Body Obedience and combines the moves of
taekwondo, karate, boxing and hip-hop dancing. This non-contact sport is characterised by
fast punches and high kicks 11 and is essentially a form of aerobic training which aims to
enhance cardiorespiratory fitness and improve balance, coordination and flexibility. To date,
50
there have been limited studies that have investigated the efficacy of Tae-bo in improving
cardiometabolic disease risk factors. The purpose of the present exploratory study was to
determine the effects of an aerobic (Tae-bo) exercise program on reducing cardiometabolic
disease risk factors in sedentary overweight and obese African female university students.
Methods and participants
Sixty-seven overweight and obese, apparently healthy African female University of Zululand
students [25 ± 5 y] were recruited for participation in the study. All participants were
sedentary for at least six months prior to beginning the intervention. Pre-participation
screening in the form of a medical health history questionnaire was conducted on all
participants. Of the original 67 that were recruited seven participants withdrew from the
study due to personal reasons. All participants completed the physical activity readiness
questionnaire (PAR-Q) and an informed consent. The participants were requested to adhere
to their normal dietary practices for the duration of the study. Ethical clearance was obtained
from the Institution‟s Faculty of Science and Agriculture Ethics Committee. Each participant
was taught to use the Borg Rating of Perceived Exertion (RPE) scale12and this was recorded
in individual log books following each exercise session.
The following American College of Sports Medicine (ACSM) and International Diabetes
Federation (IDF) „tools‟ were utilised to calculate the risk factor classification and prevalence
of metabolic syndrome amongst the participants. The ACSM,13 utilises specific criteria to
place individuals into low, moderate or high risk categories for coronary artery disease.
Participants were classified as low risk if they had ≤ 1 cardiovascular disease risk factor,
moderate risk if they had ≥ 2 cardiovascular disease risk factors and as high risk if they had
known cardiovascular, pulmonary, or metabolic diseases. The risk factors that are utilised for
51
placing a person into these categories are; hypertension, hypercholesterolemia, family
history, cigarette smoking, impaired fasting glucose, obesity and a sedentary lifestyle.
According to the IDF14for a person to be diagnosed with metabolic syndrome (MS), they
must first have elevated abdominal obesity or a waist circumference >80 cm (women), plus
any two of the following:
Hypertriglyceridaemia (triglyceride ≥1.7mmol.L-1)
Elevated blood pressure (systolic blood pressure ≥130mmHg and/or diastolic blood
pressure ≥85 mmHg)
Low HDL-C levels (≤1.29 mmol.L-1)
Impaired fasting glucose (≥5.6 mmol.L-1)
Intervention program: The exercise intervention required participants to complete 30
supervised Tae-bo sessions. The sessions were conducted by experienced instructors three
days a week for a period of 10 weeks. The duration of a session was sixty minutes. At each
training session, warm-up exercises lasted for 10 minutes, followed by a 40 min workout, and
10 min cool-down consisting of light activities and stretching. Exercise intensity progressed
from moderate intensity in the first five weeks (11 - 13 RPE) to high-intensity (14 – 16 RPE)
during the last five weeks. Table 1 provides an outline of the program.
52
Table 1 Outline of aerobic (Tae-bo) intervention program
Week
1 - 5
6–10
Intensity
Moderate
High
Borg RPE Scale
11-13
14-16
1. Warm up (10min)
Walking, step touch, double step
touch, leg curl, double leg curl,
knee up, double knee up.
Jogging, step touch, double step touch,
leg curl, double leg curl, knee up,
double knee up.
2. Workout (40min)
Routine: punches (jab, hook,
cross, upper cut) and kicks (front,
round, side and back) 135 beats
per minutes (bpm) = 135 moves
per minutes. Free arm curl, lateral
pull down, lateral raises in elbow
flexion, crunches, lunges, squats,
knee flexion, star jumps, side
punches, basic run.
Routine: punches (jab, hook, cross,
upper cut) and kicks (front, back, round,
side and hammer). (150 bpm=150
moves per minutes).Free arm curl,
lateral pull down, lateral raises in elbow
flexion, crunches, lunges, squats, knee
flexion, star jumps, side punches, basic
run, walk forward and lift knee, jump
up and down.
3. Cool down (10 min)
Static stretches (hold 15-20s X 2).
Chest, triceps, upper back,
hamstring, lower back and hip,
inner thigh, quads, calf.
Static stretches (hold 15-20s X 2).
Chest, triceps, upper back, hamstring,
lower back and hip, inner thigh, quads,
calf
Anthropometric and body composition measurements: Height (m) and weight (kg) were
measured to calculate BMI as kg.m-2. Measurements were taken wearing light clothes and
bare feet standing on a Growth Management scale (Genifis, China). The body fat
measurements were obtained using a Lange skinfold calliper (Rosscraft, Canada) from the
following sites: triceps, sub scapula, supra iliac crest, abdominal, thigh, calf. The calliper was
placed one cm away from the thumb and finger, perpendicular to skinfold, and halfway
between crest and base of fold and left for one to two seconds before reading the dial.
Measurements were taken twice and averaged. Waist circumference was taken at the
narrowest (minimum) point while the hip circumference was measured at the widest
(maximum) part of the buttocks using a tape measure on a horizontal plane.15
53
Blood pressure: Resting systolic and diastolic blood pressures were measured twice after
sitting for 5 min in the laboratory. The brachial artery auscultation technique was used with
anALPK2 sphygmomanometer and stethoscope auscultation (Microlife, Switzerland). The
measurement procedures followed the criteria of the American College of Sport Medicine.13
Resting heart rate was taken using stethoscope auscultation while participants were seated.
Systolic blood pressure was measured at the point of appearance of the Korotkoff sounds
(phase I) and diastolic BP at the point of disappearance (phase V).
Blood sample analysis: All participants reported for blood sampling in the morning between
8am and 11am after an overnight fast (9-12 hours). Blood samples were drawn at baseline
(pre-intervention), at week 6 and then at week 10 (post-intervention). Post intervention blood
samples were obtained 24h after the last exercise session. Fasting total cholesterol (TC),
high-density lipoprotein cholesterol(HDL-C), low-density lipoprotein cholesterol(LDL-C),
triglycerides (TG) and glucose concentrations were analysed in (mmol.L-1) using a Cardio
Check(R)(PA system Polymer Technology Systems, Indianapolis, USA) and CareSens II
blood glucose monitoring system (Seoul, Korea).
Statistical analysis: Data are presented as means ± SD, 95% Confidence Intervals (CI) and
effect sizes. Differences between the values at pre, mid and post-testing were analysed using
repeated measures analysis of variance (ANOVA) and a Tukey post-hoc test. The level of
statistical significance was set at p ≤ 0.05.
Results
Pre, mid and post test results are provided in Table 2. The prevalence of metabolic syndrome
using the IDF criteria was 26% at pre testing and 16% after the 10 - week Tae-bo intervention
program. The cardiovascular disease risk classification results are presented in Table 2.
Values for weight, BMI, waist circumference, glucose, triglyceride, total cholesterol, low-
54
density lipoprotein cholesterol, and systolic and diastolic blood pressure from both baseline
to mid and baseline to post showed significant (p≤0.05) improvements. The prevalence of
participants in the moderate-risk category before the intervention was 68.3% and dropped to
42.3% after the intervention. Similarly, the prevalence of participants in the low risk was
31.7% pre-intervention and increased to 57.7% at post intervention (Table 3).
55
Table 2.Group differences at pre, mid and post intervention [(mean ± SD; (95%
(CI),ES, % Δ]
Variables
Pre (n=60)
Mid (n=60)
Post (n=60)
ES
Δ%
Mid
Δ% Post
Weight
(kg)
81.86 ± 15.85
(77.44 - 86.27)
79.81 ± 15.16*
(75.59 - 84.03)
77.00 ± 15.15*
(72.78 - 81.22)
0.3
↓2.5*
↓5.9*
BMI
(kg.m-2)
32.26 ± 5.65
(30.8 - 33.72)
31.22 ± 5.55*
(29.78 - 32.65)
30.11 ± 5.46*
(28.70 - 31.52)
0.2
↓3.1*
↓6.7*
Waist
(cm)
87.59 ± 9.95
(85.02 - 90.16)
83.63 ± 9.71*
(81.13 - 86.14)
81.82 ± 10.02*
(79.23 - 84.40)
0.6
↓4.5*
↓6.6*
Hip
(cm)
118.60 ± 10.86
(115.8- 121.40)
116.20 ± 10.66*
(113.40 - 119.00)
116.20 ± 10.66*
(113.40 - 119.00)
0.4
↓2.0*
↓3.5*
SS
(mm)
212.20 ± 33.30
(203.77 - 220.99)
200.08 ± 34.97*
(191.53 - 208.63)
187.43 ± 34.64*
(178.78 - 196.09)
0.7
↓5.7*
↓11.7*
RHR
(bpm)
79.23 ± 3.76
(78.26 - 80.21)
76.25 ± 2.75*
(75.54 - 76.96)
73.27 ± 2.63*
(72.59 - 73.95)
1.8
↓3.8*
↓7.5*
Glucose
(mmol.L-1)
3.99 ± 0.59
(3.84 - 4.15)
3.83 ± 0.74*
(3.64 - 4.02)
3.61 ± 0.46*
(3.49 - 3.73)
0.7
↓4.0*
↓9.5*
LDL
(mmol.L-1)
2.12 ± 0.82
(1.89 - 2.32)
1.92 ± 0.79*
(1.71 - 2.12)
1.68 ± 0.65*
(1.51 - 1.85)
0.6
↓9.4*
↓20.8*
HDL
(mmol.L-1)
1.35 ± 0.75
(2.52 - 2.91)
1.53 ± 0.49*
(2.73 - 2.99)
1.61 ± 0.46 *
(2.69 - 2.93)
-1.0
↑13.3*
↑19.3*
TG
(mmol.L-1)
1.74 ± 0.92
(1.14 - 1.76)
1.46 ± 1.15*
(1.16 - 1.76)
1.45 ± 1.23*
(1.51 - 1.97)
0.4
↓16.1*
↓16.7*
TC
(mmol.L-1)
3.76 ± 1.02
(3.49 - 4.02)
3.5 ± 0.82*
(3.31 - 3.73)
3.36 ± 0.85*
(3.14 - 3.58)
0.4
↓6.9*
↓10.6*
TC/HDL
(mmol.L-1)
2.86 ± 0.49
(2.53 - 2.91)
2.81 ± 0.46*
(2.73 - 2.99)
2.72 ± 0.75*
(2.69 - 2.93)
-0.2
↓1.7*
↓4.9*
SBP
(mmHg)
106.30 ± 8.48
(104.10 - 108.50)
104.20 ± 11.02*
(101.40 - 107.00)
100.60 ± 8.05*
(98.55 - 102.70)
0.7
↓1.9*
↓5.4*
DBP
(mmHg)
66.73 ± 6.96
(64.93 - 68.53)
63.45 ± 9.38*
(61.03 - 65.87)
62.45 ± 7.36*
(60.55 - 64.35)
0.6
↓5.2*
↓6.7*
BMI: body mass index, RHR: resting heat rate, bpm: beats per minutes, LDL-C, low-density lipoprotein
cholesterol; HDL-C. high-density lipoprotein cholesterol; TG, triglyceride; TC, total cholesterol; SBP, systolic
blood pressure; DBP, diastolic blood pressure; SS, sum of skinfold; TC/HDL, Ratio of total cholesterol to high-
density lipoprotein; * Significant (P<0.05) difference between pre and mid, pre and post; CI, confidence
interval; SD, standard deviation; % Δ, percentage change compared to; ↓decrease; ↑increase; ES, effect size
(pre-post).
56
Table 3.Cardiovascular disease risk classification (%)
Pre (n=60)
Mid (n=60)
Post (n=60)
Low risk
31.7%
45.4%
57.7%
Moderate risk
68.3%
54.6%
42.3%
Discussion
The objective of this study was to determine if 30 group supervised sessions of Tae-bo would
be effective in reducing cardiometabolic disease risk factors in sedentary overweight/obese
African female university students. It is well established that engaging in physical activity
reduces an individual‟s risk for diabetes and cardiovascular disease 16,17 however, to the best
of the authors knowledge it is unknown if a relatively short intervention consisting of 30
sessions of Tae-bo can favorably modify the cardiometabolic disease risk profile in female
African students.
Anthropometry
Although anecdotal, the majority of students enrolled at the University of Zululand do not
meet the minimum recommended physical activity guidelines and as such it would be fair to
say that this is a strong contributing factor towards the high prevalence of overweight/obesity.
The U.S. Department of Health and Human Services17hasshown that overweight/obese
individuals are at greater risk for developing diabetes, hypertension and CVD. In addition,
Sampaliset al19have shown that relatively small reductions in weight can impart significant
health benefits. Another study of a 4 week aerobic training program recorded a 4.3%
reduction in body weight.20The participants in the current study showed an almost 6%
reduction in weight from pre to post intervention. The reduction in weight mirrored the
observations for BMI, waist and hip measurements with all these variables showing
significant reductions after the 10-week intervention program. Interestingly, significant
57
changes were already observed mid-intervention i.e. following 15 sessions or after 5 weeks,
and this trend was similar for the other dependent variables.
Blood Pressure and Resting Heart Rate
Elevated blood pressure or hypertension is estimated to affect approximately 55% of South
Africans. 21 The deleterious effects of chronically elevated blood pressure are well
documented,22 and include increased risk of cardiovascular morbidity and mortality.
Overweight/obese individuals are more at risk of developing hypertension. In the current
study, blood pressure (systolic and diastolic) was within the recommended range at all-time
points. Surprisingly, the resting blood pressure pre-intervention was lower than anticipated
for this group of overweight students. Studies conducted on other African females have
shown a propensity towards elevated blood pressure.23,24 Beneficial changes were observed
post intervention for both systolic and diastolic pressures with the mean systolic pressure
dropping by 5% and the diastolic by almost 7%. From a clinical perspective these changes are
meaningful as a recent study has shown that reductions of 9%, or 5.9 mmHg, can reduce the
risk or incidence of coronary heart disease and all-cause mortality by 14% and 7%
respectively.25Significant reductions in the participants RHR was observed following the 10
week intervention. This drop together with reductions in BP would tend to suggest that
cardiovascular efficiency had improved amongst the participants.
Blood Parameters
Glucose
As per the IDF criteria, elevated fasting blood glucose levels (≥5.6mmol.l-1) is one of the risk
factors for developing metabolic syndrome. As a screening tool, fasting blood glucose levels
can also give an indication if an individual is glucose intolerant (pre-diabetic) or diabetic.
58
Both these conditions place individuals at greater risk of developing cardiovascular disease.
A study has shown that8.1% reduction in fasting blood glucose significantly improved after 4
weeks (p<0.01) and also associated with risk factors of obesity, type 2 diabetes, and
cardiovascular disease. 17The participants in the current study exhibited a 9.5% reduction in
blood glucose concentration following the intervention. This compares favorably with the
results of a 12-week aerobics training which resulted in an improvement of insulin resistance
by 4.7% .26
Lipoproteins
Elevations in TC, TG, LDL as well as the TC/HDL ratio are considered to be independent
risk factors for the development of CVD and increased incidence of cardiac events. 27 The
most pronounced change observed in the current study for the lipoproteins was that of the
LDL which dropped by 20% (ES=0.6). Studies by Durrington et al28 and Deibert et al29 have
reported similar findings with LDL-C decreasing by almost 35% and TG by almost 13%.
This drop, together with reductions in TG, TC and increases in HDL are all significant in that
it favorably alters the participant‟s lipoprotein profile and risk of disease. It was surprising to
see such pronounced changes especially considering that the participants were not instructed
to follow a specific diet or calorie restriction program. This of course does not rule out the
possibility that the participants subconsciously altered the type and amount of food intake
during the study. Similar to the changes in blood pressure, the alterations in the lipoproteins
are of clinical significance. Zhan et al30 have shown that a reduction of 3.77% TC or 5.25%
LDL and 7.27% TG together with an increase in HDL are associated with a reduction in
cardiac events. 26
Overall the number of participants that modified their risk classification to such an extent that
they would no longer meet the IDF criteria for metabolic syndrome was 10% (Fig. 1). This is
59
a substantial drop and when one considers the worldwide prevalence of metabolic syndrome
a similar reduction globally would see millions of people significantly reduce their risk for
premature morbidity and mortality. Similarly, using the ACSM13 criteria (Table 3) there was
a 26% reduction in the number of participants who were classified as moderate risk after the
intervention.
Conclusion
The prevalence of cardiometabolic disease is increasing amongst urban and rural South
African females. In rural settings, similar to where this intervention took place, there is a lack
of infrastructure and limited opportunities exist for people to engage in organised physical
activity programs. The intervention employed in the current study was effective in reducing
the cardiometabolic disease risk profile of overweight/obese African female university
students.
60
References:
1. James WPT, Jackson-Leach R, Mhurchu CN, Kalamara E, Shayeghi M, Rigby NJ,
Nishida C, Rodgers. Overweight and obesity (high body mass index). In: Ezzati M,
Lopez A, Rodgers A, Murray CJL, eds. Comparative quantification of health risks:
global and regional burden of disease attributable to selected major risk ractors.
Geneva, World Health Organization, 2004; 949-1108.
2. Puoane T, Steyn K, Bradshaw D, Laubscher R, Fourie JM, Lambert V, Mbabanga N.
Obesity in South Africa: The South African demographic and health survey. Obesity
Res, 2002;10: 1038-48.
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65
CHAPTER 4
CONCLUSION
4.1 Conclusion
Overweight and obesity is for the most part a consequence of increased caloric intake and a
reduction in physical activity levels (World Health Organization, 2005). The prevalence of
overweight or obese adults and children is increasing and this is accompanied with an
increase in chronic disease (World Health Organisation 2013; World Health Organisation
2005). It is estimated that 48% of men and 63% of South African women are sedentary
(Mungal-Singh, 2012). Physical inactivity remains a significant problem and increases the
risk of cardiometabolic disease.
Regular exercise results in a reduction of the risk factors for obesity, type 2 diabetes, and
cardiovascular disease (Lazarevic et al., 2008; O‟Leary et al., 2006). In the present study, the
10-week Tae-bo intervention program improved the participants body composition (i.e. body
weight, BMI, percentage body fat), fasting glucose, blood lipid profile (i.e. triglycerides, total
cholesterol, low-density lipoprotein cholesterol), and resting blood pressure. The results
observed in the current study are consistent with previous reports and reinforce the positive
effect that physical activity may have on reducing an individual‟s risk of non-communicable
diseases such as, type 2 diabetes, and cardiovascular disease (Chang et al.,2009; Davidson et
al., 2009; Prasad & Das, 2009). In the present study, 10 weeks of Tae-bo training decreased
glucose by 9.5%, which is in line with previous investigations (Davidson et al., 2009;
Kamijo& Murakami, 2009).
To the best of the author‟s knowledge, this is the first study which investigated the impact
that Tae-bo has on cardiometabolic disease risk factors.
Clearly the intervention was effective in this cohort of previously sedentary individuals with
31.7% of the participants placed in the low risk category at the beginning of the study and
57.7% at the end of the study. Similarly there was a 10% reduction in the prevalence of
metabolic syndrome and changes were already observed halfway through the intervention
(i.e. at 5 weeks).
66
4.2 Study limitation
I. Participants were not given dietary guidelines to follow during the study. It is thus
tenable that some of the participants may have changed their dietary patterns and this
may have had an effect on body composition.
II. The inclusion of a non-exercising control group could have shed light on the effect (if
any) that being a research participant may have on the modification of risk factors.
That is, the mere fact that participants knew that their blood lipids, glucose etc was
being monitored may have caused them to change their normal eating and physical
activity patterns.
67
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78
Appendix A: Informed Consent to participate in a Research Study
TITLE: THE EFFECT OF A 10-WEEK TAE-BO INTERVENTION PROGRAM ON CARDIOMETABOLIC
DISEASE RISK FACTORS IN OVERWEIGHT/OBESE FEMALES OF THE UNIVERSITY OF ZULULAND
SUPERVISOR: S. J Semple, Ph.D. Associate Professor Department of Biokinetics and Sport
Science,University of Zululand, KwaDlangezwa,3886, South Africa, Telephone: 035 902 6388
CO SUPERVISOR: Dr C du Preez, Lecturer at the Department of Consumer Science, University of
Zululand, KwaDlangezwa,3886, South Africa, Telephone: 035 902 6388
Student: Musa L Mathunjwa
Department of Biokinetics and Sport Science
KwaDlangezwa
3886
South Africa
Telephone: 035 902 6886
PURPOSE AND BACKGROUND
Under the supervision of Prof S Semple and Dr C du Preez at the University of Zululand, Mr M
Mathunjwa a graduate student in research from the Department of Biokinetics and Sport Science is
conducting research on the effect of a 10-week Tae-bo intervention program oncardiometabolic
disease risk factor in overweight/obese femalesstudent of the University of Zululand. The purpose of
this study is to see if Tae-bo intervention will have an impact on the cardiometabolic risk factors in
overweight/obese females.
This study will investigate the effect of Tae-bo interventions on cardiometabolic diseases such as:
resting heart rate, resting blood pressure, glucose and cholesterol (TC, TG, LDL, HDL, TC/HDL).
You are being invited to take part in this research study because you are within the body weight
range for this study, and you do not have any medical conditions that would prohibit you from
participating in moderate to vigorous activity. Moderate activity is defined as activity similar to brisk
walking where you can also have a conversation, with vigorous activity defined as activity is walking
at a faster pace and you cannot have a conversation because you are breathing deeper and faster.
Females invited into this study have to be between 20-30 years of age. This study is being performed
on a total of 67 individuals at the University of Zululand. If you decide to take part in this research
study, you will undergo the following procedures that are not part of your standard medical care:
Screening Procedures: Procedures to determine if you are eligible to take part in a research study
are called “screening procedures”. For this research study, the screening procedures include: You
will complete a physical activity readiness questionnaire (PAR-Q), and this will take approximately 5
minutes to complete. You will also complete a detailed medical history, and this will take
approximately 20 minutes to complete. These questionnaires will allow the investigators to
determine if you have any significant medical condition that would indicate that exercise is unsafe
for you. Participants cannot be pregnant, and you will be required to accurately report whether you
79
are pregnant to the investigators prior to beginning of this study and during the study if your status
should change.
Procedures and Protocol
Experimental Procedures: If you qualify to take part in this research study, you will undergo the
following experimental procedures: You will first be asked to complete a series of questionnaires,
and it is estimated that you will be able to complete these questionnaires in approximately
30minutes. These questionnaires will provide information about your health. Your body weight,
body composition, blood pressure, physical fitness, muscular strength, physical function, level of
physical activity, and food intake will be measured. These assessments will take place at the
department of Biokinetics and Sport Science at the University of Zululand, and these assessments
will be completed in approximately 90 minutes. A brief description of these assessments follows.
A. Body Weight and Height (2 minutes): Your body weight will be measured using a standard
detector scale. Your height will be measured with a ruler that is attached to a flat wall. These will be
measured at 0, 5, and 10 weeks during this study.
B. Body Composition (5 minutes): Your body composition is the amount of fat weight and lean
weight (muscle and bone) that you have on your body. Your body composition will be measured
using a skin fold calliper technique. This procedure requires 6 sides (triceps, Sub scapular,
abdominal, thigh, calf). A small pinch with skin fold calliper and index and thumb signal that is not
harmful to you and that you will not feel is uncomfortable because you will be aware.
Measurements of your waist and hip areas will also be made using a measuring tape. These
measures will be made at 0, 5, and 10 weeks during this study.
C. Blood Pressure (5 minutes): Your blood pressure will be measured using a standard blood
pressure cuff and will follow standard measurement procedures. Blood pressure will be measured at
0, 5, and 10 weeks during this study.
D. Cardiorespiratory Fitness (3 minutes Harvard step test): Measurement of your cardiorespiratory
fitness will provide information about how fit your heart and lungs are to perform exercise.
E. Muscular Strength (hand grip strength): Muscular strength refers to the maximum amount of
weight you can lift and is specific to each muscle group. Your muscular strength will be estimated for
upper body by performing a hand grip strength calliper. The exercise uses the hand muscles.
Muscular strength will be measured at 0, 5, and 10 weeks during this study.
F. Skill-related fitness (20 minutes): Physical function refers to how well you can perform common
tasks. Your physical function will be measured by having you perform a series of tasks that include
the following: performing a T-test (running). Performing a stork test (test for balance on your legs)
for up to 10 seconds.Performing power (horizontal jump). These tasks will be measured at 0, 5, and
10 weeks during this study.0, 3, and 6 months during this study.
G. Dietary Patterns (60 minutes): During the intervention, you will complete a 3 day food dairy about
the amount and type of food that you eat for three times a week. You will also complete
questionnaires about factors such as your mood, general health, and other things that may affect
your exercise and eating behaviours. Participants who have a positive score on the mood measure
that is being used in this study will be referred to their personal physician or other appropriate
medical personnel for follow-up care. You will also be taught how to decrease the amount of food or
fat that you eat, and will be encouraged to decrease fat intake to 20-30% of your total calories.
These questionnaires will be completed for every 2 weeks during this study.
80
RISKS AND BENEFITS:
The possible risks of this research study may be due to the exercises that you will be performing and
the assessments that will be performed.
RISKS
A. Risks of Exercise and test of Physical Fitness: There are moderate risks associated with
participating in an exercise test, a physical function test, and a regular exercise program.
During exercise, you may experience a serious cardiac (affecting your heart) event, an
arrhythmia (your heart beats at a pace that is not normal), or chest pain. An example of a
cardiac event would be a heart attack or another medical condition that causes damage to
your heart or cardiovascular system. The possibility of experiencing a serious cardiac event
has been estimated to be less than 1 per 20,000 in exercising adults, with the risk of death
during a maximal exercise test being less than 0.5 per 10,000 tests. Therefore, the risk is of
this happening to you is rare, because it occurs in less than 1% of people (less than 1 out of
100 people). In addition, during exercise, you may experience an increase in heart rate, an
increase in blood pressure, shortness of breath, general fatigue, and in some cases muscle
soreness. The risk of this happening to you is likely because these occur in more than 25% of
people (more than 25 out of 100 people). When testing muscular strength you may
experience muscle strain, with the risk of this happening to you infrequent because it occurs
in 1-10% of people (1-10 out of 100 people). In the event that you experience a serious
medical condition during your exercise testing session or during a supervised exercise
session, the session will be stopped and appropriate emergency medical care will be
provided. This may include providing CPR until Paramedics or other appropriate medical
personnel arrive.
B. Risk Associated with Completion of Questionnaires: You may experience non-physical risks
such as boredom, frustration, stress, and time constraints when completing the
questionnaires. The risk of this happening to you is likely because this occurs in more than
25% of people (more than 25 out of 100 people).
C. Risk Associated with Participating in the Intervention: Attending group sessions has been
shown to be effective for weight loss. However, attendance at these sessions you may find
yourself sharing information about yourself and your weight loss efforts to the group
members and unscientific argument may arise.
There are also possible benefits of this research study that may be due to the exercises that you
will be performing.
However, there is no guarantee that any or all of these changes will occur as a result of you
participating in this study.
BENEFITS
A. Benefits of Exercise: The benefits of participation in an exercise program have been
shown to include improvements in physical fitness, weight loss, improvements in blood
pressure, and improvements in blood cholesterol levels. However, there is no guarantee
that any or all of these changes will occur as a result of you participating in this study.
If we should find out about a medical condition you were unaware of, with your written permission,
this information will be shared with the doctor of your choice.
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NEW INFORMATION: You will be promptly notified if any new information develops during the
conduct of this research study, which may cause you to change your mind about continuing to
participate.
COSTS AND PAYMENTS: Neither you, nor your insurance provider, will be charged for the costs of
any of the procedures performed for the purpose of this research study. However, there is no
guarantee that any or all of these changes will occur as a result of you participating in this study.
COMPENSATION FOR INJURY: University of Zululand researchers and their associates who provide
services at the University of Zululand Medical recognize the importance of your voluntary
participation in their research studies. These individuals and their staffs will make reasonable efforts
to minimize, control, and treat any injuries that may arise as a result of this research. If you believe
that you are injured as a result of the research procedures being performed, please contact
immediately the researcher.
CONFIDENTIALITY: Any information about you obtained from this research will be kept as
confidential (private) as possible. All records related to your involvement in this research study will
be stored in a locked file cabinet. Your identity on these records will be indicated by a case number
rather than by your name, and the information linking these case numbers with your identity will be
kept separate from the research records. In addition, all research databases will have password
controlled access, and this will be controlled by the researchers. Only the researchers listed on the
first page of this form and their staff will have access to your research records. You will not be
identified by name in any publication of research results unless you sign a separate form giving your
permission (release).
This research study will involve the recording of current and/or future identifiable medical
information from your hospital and/or other (e.g. physician office) records. The information that will
be recorded will be limited to information concerning medical clearance from your physician to
participate in this research study. This may include information related to coronary heart disease risk
factors such as blood pressure, blood cholesterol, or other medical conditions that may increase the
risk of heart disease and/or indicate that exercise participation may be unsafe for you. This
information will be used to determine whether it is safe for you to participate in this research study.
In addition to the investigators listed on the first page of this authorization (consent) form and their
research staff, the following individuals will or may have access to identifiable information related to
your participation in this research study.
RIGHT TO PARTICIPATE OR WITHDRAW FROM PARTICIPATION:
Your participation in this research study, to include the use and disclosure of your de-identifiable
information for the purposes described above, is completely voluntary. (Note, however, that if you
do not provide your consent for the use and disclosure of your identifiable information for the
purposes described above, you will not be allowed, in general, to participate in the research study.)
Whether or not you provide your consent for participation in this research study will have no effect
on your current or future relationship with the University of Zululand. Whether or not you provide
your consent for participation in this research study will have no effect on your current or future
medical care at a University of Zululand clinic or affiliated health care provider or your current or
future relationship with a health care insurance provider. You may withdraw, at any time, your
consent for participation in this research study, to include the use and disclosure of your de-
identifiable information for the purposes described above. (Note, however, that if you withdraw
your consent for the use and disclosure of your identifiable information for the purposes described
above, you will also be withdrawn, in general, from further participation in this research study.) Any
research information recorded for, or resulting from, your participation in this research study prior
82
to the date that you formally withdrew your consent may continue to be used and disclosed by the
investigators for the purposes described above. To formally withdraw your consent for participation
in this research study you should provide a written and dated notice of this decision to the
investigator of this research study at the address listed on the first page of this form.
It is possible that you may be removed from the research study by the researchers if, for example,
your health status changes and it does not appear that it is safe for you to continue to reduce your
food intake, exercise, or lose weight. You will also be removed if you should become pregnant during
this study.
VOLUNTARY CONSENT The above information has been explained to me and all of my current
questions have been answered. I understand that I am encouraged to ask questions, voice concerns
or complaints about any aspect of this research study during the course of this study, and that such
future questions, concerns or complaints will be answered by a qualified individual or by the
investigator(s) listed on the first page of this consent document at the telephone number(s) given. I
understand that I may always request that my questions, concerns or complaints be addressed a
listed investigator. By signing this form, I agree to participate in this research study. A copy of this
consent form will be given to me.
FREEDOM OF CONSENT:
Your permission to perform this test is voluntary. You are free to stop the testing at any time, if you
so desire.
I have read this form and understand the test procedures that I will perform, as well as the related
risks and possible discomforts. With full knowledge of this, and having had an opportunity to ask
questions that have been answered to my satisfaction, I consent to participate in this testing
procedure
____________________ __________________ ______________
Participant Signature Date
__________________ __________________ ______________
Reseacher Signature Date
83
Appendix B: Data sheet
Name & Surname
Gender
Age
Wt
Ht
BMI
Test/Measurement
1st
Assessment
2nd
Assessment
3rd
Assessment
Date
Weight
Resting Heartrate
Resting Blood Pressure
Glucose:
LDL
HDL
Tri
Total Cholesterol
Skin Folds
Triceps
Sub Scap
Supra iliac
Abdominal
Thigh
Calf
84
Appendix C: General Health History Questionnaire
Subject name:___________________________ Student number: _____________________
Date of birth: ___________________________ Gender_____________________________
Residence_________________________ Race: ____________________________________
Do you have, or have you been previously diagnosed with any of the following medical
conditions? (√)
No
Ye
s
Unsu
re
Approximate
Date of
Diagnosis
Describe the Problem
1.Heart problem
2.Stoke
3.High blood
pressure
4.Obesity
5.Diabetes
6.Asthma or
pulmonary diseases
7.Lower back pain
8.Pregnancy
9.Osteoporosis
10.Fainting spells
11.Angina (Chest
pain or exertion)
12.Irregular heart
problems
13.Emotional/
Psychiatric Problems
14.Drug/ Alcohol
Problems
15.Hypertension and
cardiovascular
diseases
1. Do you have any medical problems that would prevent you from participating in the
10 week Tae-bo intervention program? _____yes ______no
If yes, please describe the
problem:___________________________________________________________________
_________
2. Is it possible that you will leave the University in the next 10-week? ______yes
______no Please explain___________________________________
3. Are you currently pregnant? __yes __no
4. Were you pregnant in the past 6 months? __yes __no
5. Do you plan to become pregnant in the next 3 months? __yes __no
6. Have you gone through menopause or the change of life? __yes __no.
7. Have you had a hysterectomy? __yes __no.
8. When was your last menstrual period? DATE:____ /____/____.
9. Do you take: Birth Control Pills? __yes __no
85
Estrogens (ie.Premarin)? __yes __no
Progesterone (ie.Provera)? __yes __no
Exercise (Physical Activity)
The next few questions are about exercise, recreation, or physical activities other than your
regular job duties.
1 Have you been active or involved in any sport or physical activities such as running
(moderate or high intensities) for the past 6 months?
1 Yes 2 No 3 Don„t know / Not sure 4 Refused
2. What type of physical activity or exercise did you spend the most time doing during the
past month?
1 Don„t know 2 Refused
3 How many times per week or per month did you take part in this activity during the past
month?
1_ _ Times per week 2 _ _Times per month 3 _ _Don„t know / Not
sure
4 And when you took part in this activity, for how many minutes or hours did you usually
keep at it?
1_:_ _ Hours and minutes 2_ _ _Don„t know / Not sure 3_ _
_Refused
5 What other type of physical activity gave you the next most exercise during the past month?
1_ _ _ _ (Specify) 2_ _ _ _ No other activity 3_ _ _ _ Don„t know / Not
Sure
4_ _ _ _ Refused
6 How many times per week or per month did you take part in this activity during the past
month?
1_ _ _ _Times per week 2_ _ _ _Times per month 3_ _ _ _Don„t know / Not sure
4 _ _ _ _Refused
7 And when you took part in this activity, for how many minutes or hours did you usually
keep at it?
1_:_ _ _ Hours and minutes 2_ _ _ _Don„t know / Not sure 3_ _ _ _Refused
8 During the past month, how many times per week or per month did you do physical
activities or exercises to STRENGTHEN your muscles? Do NOT count aerobic activities like
walking, running, or bicycling. Count activities using your own body weight like yoga, sit-
ups or push-ups and those using weight machines, free weights, or elastic bands.
1_ _ _ _Times per week 2_ _ _ _Times per month 3_ _ _ _Never 4_ _ _
_Don„t know / Not sure 5_ _ _ _Refused
86
Disability
The following questions are about impairments you may have.
1 Are you limited in any way in any activities because of physical, mental, or emotional
problems?
1 _ _ _ _Yes 2 _ _ _ _No 3 _ _ _ _Don„t know / Not Sure 4 _
_ _ _Refused
2 Do you now have any health problem that requires you to use special equipment, such as a
cane, a wheelchair, or a special telephone?
1_ _ _ _ Yes 2 _ _ _ _No 3 _ _ _ _Don„t know / Not Sure 4 _
_ _ _Refused
Alcohol Consumption
1 Do you consume alcohol? 1_ _ _ _Yes 2_ _ _ _No
2. During the past 30 days, how many days per week or per month did you have at least one
drink of any alcoholic beverage such as beer, wine, a malt beverage or liquor?
1 _ _ _ _ Days per week 2 _ _ _ _Days in past 30 days 3 _ _ _ _No drinks in past
30 days 4_ _ _ _ Don„t know / Not sure 5 _ _ _ _Refused
3 _ _ _ _One drink is equivalent to a 12-ounce beer, a 5-ounce glass of wine, or a drink with
one shot of liquor. During the past 30 days, on the days when you drank, about how many
drinks did you drink on the average?
NOTE: A 40 ounce beer would count as 3 drinks, or a cocktail drink with 2 shots would
count as 2 drinks.
1_ _ _ _ Number of drinks 2_ _ _ _ Don„t know / Not sure 3 _ _ _ _Refused
4 _ _ _ _Considering all types of alcoholic beverages, how many times during the past 30
days did you have X [X = 4 for women] or more drinks on an occasion?
1_ _ _ _Number of times 2_ _ _ _None 3_ _ _ _Don„t know / Not sure
4 _ _ _ _Refused
5 During the past 30 days, what is the largest number of drinks you had on any occasion?
1_ _ _ _Number of drinks 2_ _ _ _Don„t know / Not sure 3_ _ _ _Refused
Smoke
1. Over the past 6 months, have you regularly smoked cigarattes, pipes, cigers, or used
chewing tobacco?
Please describe daily habit
Cigarettes _ _ _ _ yes _ _ _how often a day _ _ _no ______________________
Pipe _ _ _ _ yes _ _ _how often a day _ _ _no ______________________
Chewing Tobacco _ _ _ yes _ _ _how often a day _ _ _no ______________________
87
Appendix D: Publication Letter
3200
2
‘5
14
November 4, 2013
Musa Mathunjwa
University of Zululand
KwaDLangezwa 3886 South Africa
Dear Dr. Mathunjwa,
Congratulations! Your manuscript, MS #12-144 titled “A 10-week aerobic exercise program reduces
cardiometabolic disease risk in overweight/obese African female university students” has completed the
review process employed by the editorial board of Ethnicity & Disease. Your submission is tentatively schedule to
be published in 2013 Volume 23 No 2 or Volume 23 No 3 of the journal. Please return the enclosed copyright
transmittal agreement signed by all authors to our office as soon as possible. Your manuscript will be proofread
and a galley proof will be sent to you. Note that the publisher will assess you a nominal fee for any changes you
choose to make at the page-proof stage. You will receive correspondence from the managing editor near the time
of publication.
We would also like to invite you to submit a brief (approximately 500 words), patient-friendly summary of your
article for concurrent publication. This summary should emphasize the results of your work and link them to real-
world health concerns, in a writing style and technical level that could be easily understood by a high-school
graduate. Your summary will be published—with other summaries—in a special “For the Patient” section of the
journal and may be made available for the general public to access electronically from our website. Please
forward an electronic file to terry-jackson@ishib.org or ethndis@ishib.org within 2 weeks after receiving your
acceptance letter.
Our most powerful tool to improve the health of all people is education. For 23 years our journal has been a
potent educational tool for healthcare professionals, and our next step will be to extend this education to those
who, ultimately, need it most. If you have any questions, please contact Terry E. Jackson, Asst. Managing Editor
at 770-898-7910 or 770-940-0385 or via email to terry-jackson@ishib.org. Thank you for your interest in Ethnicity
& Disease.
Sincerely,
Keith C. Norris, MD
Editor-in-Chief
157 Summit View Drive
McDonough, Georgia 30253
USA
Telephone: 770-898-7910 or 770-940-0385
