An Eight-Week Supervised Fitness Program in Reducing Cardiovascular Risk Factors Among African-American College Students

Cardiovascular disease (CVD) is the leading cause of death of all races in the United States. African-Americans are more likely to die from CVD than whites. One hundred and forty-six African-Americans college students were recruited from a historical black college (HBCU) in North Carolina. A fitness course (PEDU 1541) was required for all students at North Carolina Central University (NCCU). An eight-week program was designed by several certified fitness instructors who teach this course at NCCU. This study was to exam the effectiveness of an 8-week exercise program in reducing CVD risk factors, including cardiovascular fitness, waist circumferences, and body fat percentage (BF%). Students’ BMI, body composition, cardiovascular fitness, muscular endurance, and trunk flexibility were assessed before and after completion of this 8-week supervised program. All the preand post-measurements of the 146 students were compared with a paired-t test to see if there were any significant changes. After 8 weeks of participation in this program, all measurements except their body fat composition improved (p< 0.05). Students’ diet or calorie intake was not controlled during the program in this study. Therefore, no significant change was found in their answers to the modified questionnaire of health behaviors, including alcohol, tobacco, vegetable consumptions before and after they completed this 8-week fitness course. Therefore, increase physical activity level alone may not be sufficient to reduce all risks of CVD in African-American population.


Introduction
Cardiovascular disease (CVD) is the leading cause of death for women and man of all races and ethnicities in the United States [1]. However, racial differences in mortality rate have been well documented [2]. In 2015, 46% of male and 48.3% of female among African Americans age 20 or older have CVD. CVD caused the deaths of 47,130 black females and 46,081 black males; 21% more than non-Hispanic whites [1]. Many risk factors have been associated with CVD. Some risk factors cannot be modified, such as family history, while some are modifiable, such as physical inactivity, tobacco, diet, blood lipids, hypertension, and obesity. Studies also showed a higher prevalence of risk factors such as hypertension, diabetes mellitus, obesity, cigarette smoking, and left ventricular hypertrophy might account for the disproportionate rate of coronary heart disease mortality in African Americans [3][4]. In addition, traditional family food with high fat, sugar and sodium combine with a less active lifestyle may further pose the problem on their health for some African Americans [5].
Decades of research have shown that diet and physical activity have a major impact on CVD, diabetes, and disease risks. For example, some dietary cholesterol had significant effects on increasing total cholesterol concentrations in humans and animals [6][7]. Others showed that dietary and other lifestyle modifications, such as a reduced salt intake, increased physical activity, and weight loss can lower blood pressure and reduce incidence of hypertension and CVD [8]. Many physical activity studies also showed low cardiorespiratory fitness was a major risk factor for CVD [9][10][11]. Furthermore, exercise regimens not only can lower blood pressure, but also reduce the cardiovascular events and the mortality rate by 35% in patients with CVD [12][13][14][15][16]. However, diet pattern and lifestyle may vary Factors Among African-American College Students between minority and majority population due to the cultural influence. The effects of exercise regimens on reducing different CVD risk factors among different race and ethnicities were not recorded. Therefore, additional research on the effects of exercise on African Americans is needed to refine the current public health guideline regarding physical activity.

Methodology
One hundred and fifty-six African American college students, age between 18-25, and did not have any chronic disease including type 2 diabetes, hypertension and CVD were recruited from North Carolina Central University, a historically black university. All participants registered for the required fitness class (PEDU 1541) were taught by the same instructor during the year of 2015 and 2016. Each participant was required by the Institutional Review Board (IRB) to sign a consent form before participating in the study.

Data Collection
Upon enrollment, baseline data of BMI, waist and hip circumference, percentage body fat, blood pressure, and cardiovascular fitness were collected from each participant. The percent body fat was estimated with a TANITA body composition analyzer. The cardiovascular fitness was measured by the recovery heart rate (bpm) after a 3-minute step exercise, one-minute sit-up, one-minute push-up and one-mile run. Their flexibility was also measure with a sit and reach test. In addition, a modified questionnaire of Youth Risk Behavior Surveillance System (CDC, 2009) for young adults (Appendix A), including the questions related to tobacco, alcohol, drug use, body weight, diet, and physical activity, was given to assess any confounding factors that may affect the result besides the exercise program. All the variables and the questionnaire were also administered at the 4 th and 8 th week after enrollment to each group. The data of the students who did not complete the 8-week exercise program and the initial, 4 th , and 8 th week assessments were excluded from data analysis.

Exercise Program
All participants met with the instructor twice per week for 8 weeks. Each class was 50 minutes, including a 5-10 minutes warm-up and a 40-45 minutes work out sessions. During the work-out session, students were instructed to perform a combination of muscle-strengthen and Cardio exercise with supervision by the fitness instructor. The muscle-strengthen exercise include leg curl, leg press, shoulder press, biceps curl, triceps extension, chest press, abdominal, and low back muscle groups was instructed at the first day. Each participant was instructed to pick at least one exercise per large muscle group for 1 set of 15 reps for the first week, and gradually increase each week to 4 sets of 6 reps at the 8 th week. Participants were also instructed to perform one of the Cardio exercise including brisk walking, bicycling, step aerobics, and jogging for 20 minutes for the first three weeks, 25 minutes from 4 th to 6 th week, and 30 minutes for the last two weeks. A work-out log to record the exercise and time was required to be filled out by each participant after completion of the 8-week program (Appendix B).

Quantitative Analysis
Changes between the pre-and post-training for anthropometric, body composition, and muscular strength, endurance and post-exercise heart rate were analyzed with a paired-t test. The significant level was assessed at p≤ 0.05. All analysis was conducted using IBM SPSS statistical software, version 22.

Initial Assessment
One hundred and forty-six (48 males and 98 females) students' data were analyzed. Their mean age was 19.24± 1.71 years old. The average BMI of the male students was 27.58± 6.60 and female students was 28.28± 7.88 at the initial body composition assessments. Both gender groups were overweight (between 25~30) with increased risk of CVD based on the BMI classification for adults (Table 1). Our male students' average BF% was 22.55± 10.40 considered average (between 18~24%) but female students' average BF% was 32.90± 10.63 considered obese (>32%) based on the Percent BF Classification from American Council of Exercise (ACE) Personal Trainer Manual (2015) ( Table 2). As for their averaged waist circumferences, both groups were within the low risks classification (male between 32-39in; female between 27-35in) for CVD (Table 3).

Fitness Assessments
There was no significant change at the end of the 4 th week of the program in any of the variable assessed. However, significant improvements were shown in: waist circumference (2.04% decrease in males and 2.51% decrease in females), muscle endurance in sit-up (23.87% increase in males; 32.55% increase in females), trunk flexibility (9.39% increase in males; 12.57% in females), and post-exercise heart rate (15.56% decrease in males; 3.48% decrease in females) at the 8 th week assessments (Table 3& 4).

Body Composition Assessments
The average body weight of the male students was increased after 8 weeks of training while females' weight did not change. There was no significant change of their BF% in either group, which suggested that this 8-week supervised fitness program improved their cardiovascular fitness, muscular endurance and flexibility of the participants without lowering their body weight or BF% (

Health Behavior Assessments
In addition, there was no significant change to the students' answers to the modified questionnaire of health behaviors, including alcohol, tobacco, vegetable consumptions after they completed this 8-week fitness course. Even though the students were required to read the topics related to healthy behaviors related to cardiovascular fitness and risks, this alone did not change their behaviors with healthier diet and living. Therefore, incorporating sessions focused on the knowledge of nutrition, and the alcohol and tobacco effects on cardiovascular health may be needed.

Discussion
Obesity (BMI), Waist circumference, BF% were associated with increased risk of developing CVD, while fitness level was associated with reducing risks of CVD. Studies have shown positive effects of exercise programs on reducing some of the CVD risk factors with black and non-black youth and adolescences [17][18][19]. However, few studies have assessed the effects of school-based fitness programs on college students, who are at their crucial moment in developing their adulthood habits and lifestyle. A recent study had shown that, sedentary behavior of young adults University students was negatively associated and number of self-reported sedentary extracurricular activities was positively associated with waist circumferences [20]. In addition, their moderate and vigorous physical activities were negatively associated with BMI, which suggested that reducing college students' sedentary activities and increasing their vigorous physical activities level and time could reduce their waist circumference and BMI, and thus reduce their risks of developing cardiovascular diseases. Therefore, interventions to reduce sedentary behaviors and increase healthy eating is needed for this population. This study showed that an eight-week supervised fitness program, which targeted muscle strength, endurance and flexibility, was able to reduce several risk factors of CVD among African American college students. However, other factors, such as blood lipids, blood pressure were not assessed in this study, and should also be assessed in future studies.
After completing this 8-week program, students' body weight or body fat % did not change, suggesting a longer intervention period may be needed. In addition, there was no health behavior changes with their alcohol, or vegetable consumption. Increased calorie intake during the program may have caused the no change or some increase in their body weights. Therefore, a nutrition class and dietary plan will be needed and students' calorie intake should also be assessed in the future studies.

Conclusion
This eight-week, twice per week, supervised fitness program was able to reduce their waist circumference, and improve muscular endurance, flexibility and fitness level of the African American college students, but not their body weight or BF%. Future studies will be needed to assessed the effectiveness of this program on other CVD risk factors, such as blood lipids, and hypertension. A dietary plan should also be incorporated with the program in the future, because increase physical activity level alone may not be sufficient to reduce the risk of CVD in African-American college-aged students or in general population.

Appendix A. Subject #______________
This survey is about health behavior. It has been developed so you can tell us what you do that may affect your health. The information you give will be used to develop better health education for young people like yourself.
DO NOT write your name on this survey. The answers you give will be kept private. No one will know what you write. Answer the questions based on what you really do.
Completing the survey is voluntary. The questions that ask about your background will be used only to describe the types of students completing this survey. The information will not be used to find out your name. No names will ever be reported. Make sure to read every question. During the past 30 days, did you take any diet pills, powders, or liquids without a doctor's advice to lose weight or to keep from gaining weight? (Do not include meal replacement products such as Slim Fast.) A Yes B No The next 8 questions ask about food you ate or drank during the past 7 days. Think about all the meals and snacks you had from the time you got up until you went to bed. Be sure to include food you ate at home, at school, at restaurants, or anywhere else.
15. During the past 7 days, how many times did you drink 100% fruit juices such as orange juice, apple juice, or grape juice? (Do not count punch, Kool-Aid, sports drinks, or other fruit-flavored drinks.) A I did not drink 100% fruit juice during the past 7 days B 1 to 3 times during the past 7 days C 4 to 6 times during the past 7 days D 1 time per day E 2 times per day F 3 times per day G 4 or more times per day 16. During the past 7 days, how many times did you eat fruit? (Do not count fruit juice.) A I did not eat fruit during the past 7 days B 1 to 3 times during the past 7 days C 4 to 6 times during the past 7 days D 1 time per day E 2 times per day F 3 times per day G 4 or more times per day 17. During the past 7 days, how many times did you eat green salad?
A I did not eat green salad during the past 7 days B 1 to 3 times during the past 7 days C 4 to 6 times during the past 7 days D 1 time per day E 2 times per day F 3 times per day G 4 or more times per day 18. During the past 7 days, how many times did you eat potatoes? (Do not count french fries, fried potatoes, or potato chips.) A I did not eat potatoes during the past 7 days Factors Among African-American