Effects of Different Modes of Exercise Training on Body Composition and Risk Factors for Cardiovascular Disease in Middle-aged Men.

BACKGROUND: Previous studies have indicated that exercise training improves body composition and cardiovascular disease risk factors. The aim of the present study was to investigate the effect of 12 weeks of aerobic, strength and combined training on body composition, intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and C-reactive protein (CRP) in sedentary middle-aged men.
METHODS: Forty-seven male aged 40-60 years voluntarily participated in this study and were divided in four groups: aerobic (n = 12), strength (n = 12), combined (n = 11), and control (n = 12) groups randomly. Body composition, ICAM-1, VCAM-1, and CRP were measured before and after 12 weeks. Data were analyzed using paired t-test and analysis of variance statistical methods.
RESULTS: There were significant differences in body weight between aerobic and strength training (P = 0.004) and aerobic and control groups (P = 0.018), body mass index between combined and strength training (P = 0.004) and combined and control groups (P = 0.001), fat percentage between aerobic training and control group (P = 0.017) and combined training and control groups (P = 0.004), and finally, fat-free mass between aerobic and strength training (P = 0.024), aerobic and combined training (P = 0.0001), strength and control groups (P = 0.035), and combined and control groups (P = 0.0001).
CONCLUSIONS: The results indicated that 12-week workout, 20-60 min/session, 3 days a week of moderate intensity exercise improved body composition, ICAM-1, VCAM-1, and CRP compared to those who did not participate in any training. However, all three types of exercises had small benefits on body composition, ICAM-1, VCAM-1, and CRP in sedentary middle-aged men, and the importance of combined training required further investigations.

Introduction

Sedentary lifestyle is accompanied by increased prevalence of cardiovascular diseases (CVD) and almost two million deaths are caused by lack of exercise worldwide.[1] Sedentary lifestyle increases the risk of CVD in middle-aged individuals. However, participating in exercise training and being physically fit can reduce mortality.[2] Long-term studies show that decreased physical fitness in middle-aged individuals increases the risk of CVD up to 50%, so the lifetime benefits of regular exercise are accompanied by prevention of cardiac risk factors.[345]

Aging is associated with changes of body composition, physical functioning, and substrate utilization and muscle atrophy. Muscle atrophy leads to declining muscle strength and function, along with diminished quality of life. Age-related changes in body composition and muscle atrophy play an important role in frailty.[67] Exercise training influence on improving quality of life is correlated with decreasing body fat, obesity, increasing muscle strength, health improvement, and alleviating muscular pains. Furthermore, exercise training plays an important role in decreasing the risk of CVD, hypertension, osteoporosis, cancer, and diabetes.[89]

Chronic diseases account for approximately 60% of all deaths worldwide.[10] Recently, numerous other CVD risk factors and markers have been identified. Although the pathological role of these new investigated risk factors in the development of CVD is severely debated, their role is added to traditional risk factors in preventing and anticipating CVD and related death.[111213] A number of recently identified factors associated with inflammation and which are new risk factors for CVD and form plaque on vessels walls are intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and C-reactive protein (CRP).[1415] However, the pathogenic role of these risk factors in the development of CVD is controversial. One of the most sensitive cellular markers in identifying the formation of atherosclerotic plaque on the walls of the vascular endothelial is attaching cell molecules such as ICAM-1 and VCAM-1.[1617] ICAM-1 and VCAM-1 are two main groups of four groups of cell adhesion molecules.[18] These two molecules are glycoprotein that exist in some areas, such as vascular endothelial cells, leukocytes, and platelets and play the role of mediator in inflammation. Studies on the effect of aerobic and strength exercise on values of these adhesion molecules in adults are controversial.[1920] Rankovic et al. surveyed the effect of aerobic training on the levels of VCAM-1 in middle-aged individuals and observed a significant decrease in the levels of VCAM-1.[21] Olson et al. studied the effects of 1-year strength training on middle-aged women and did not observe any significant reduction in the levels of VCAM-1.[22]

CRP is a spherical plasma protein that is involved in systemic inflammatory response in most vertebrates and invertebrates. Rapid increase in CRP synthesis a few hours after infection or tissue damage indicates that it participates in host defense and is a part of the innate immune response. In liver cells, CRP is synthesized mainly by interleukin-6 (IL-6).[2324] Increased CRP levels in blood cause tissue inflammation, lipid deposition, and blockage in vessel walls. The primary strategy for reducing CRP is medication therapy.[2526] Libardi et al. examined the effects of strength, endurance, and combined training on CRP levels in middle-aged men and observed no statistically significant differences before and after exercise training.[27] Olson et al. examined the effect of 1-year strength training in middle-aged women and observed a significant improvement in CRP in strength training group.[22]

Effect of aerobic and strength exercise in prevention and reduction of CVD has been studied in many researches.[2829] Given the role of inflammation in CVD, one of the mechanisms to reduce the disease is to improve body composition and inflammatory markers by regular aerobic and strength exercise in middle-aged people. In the past decade, many studies have been performed on the effects of aerobic and strength training on body composition and inflammation remarks; however, the results of these studies have been associated with many contradictions on the basis of case, type, and nature.[3031] It is proven that daily physical activity improves general health in healthy middle-aged sedentary people. Most people do not have much time for exercise training, so finding the most effective and less time consuming exercise training is important.[432] The researches comparing the effectiveness of aerobic, strength, and combined training are limited and further researches seem necessary to better understand the effects of different types of exercise training on body composition and cardiac risk factors. Considering the limited studies about influence of different modes of exercise training on body composition, ICAM-1, VCAM-1, and CRP in sedentary middle-aged men, more future researches are necessary to clarify physiological response of different modes exercise training. Thus, in this study, we examined the effect of 12 weeks of aerobic, strength and combined training on body composition, ICAM-1, VCAM-1, and CRP in sedentary middle-aged men.

Methods

Subjects

This was a quasi-experimental study. Participants were informed of the objectives, procedure, as well as possible risks of training programs and their written information consent. Individuals were selected according to their age, <30 body mass index (BMI), physical health, not attending in exercise training for 6 months before the study, normal state of variables at pretest, lack of a specific diet, medication, and smoking. Exclusion criteria consisted of not participating in more than two training sessions and unwillingness to continue to participate in the study. The primary criteria for evaluating participants' health were to check the physical examination by a physician and review the health questionnaire. None of the participants were affected by chronic autoimmune, systemic, CVD, hepatic, or other diseases which can continuously change the body composition, ICAM-1, VCAM-1, and CRP status. In addition, at the preliminary session, the participants were asked not to change their diet and lifestyle during the 12 weeks. Qualified individuals were randomly assigned into four groups: aerobic (n = 12), strength (n = 12), combined (n = 11), and control (n = 12) groups. Researchers monitored the training sessions and the training sessions were held in the gym equipped with advanced devices.

Aerobic training program

The participants performed the training sessions using a treadmill three times a week (on nonconsecutive days) and 20 min presession (60% of maximum heart rate [HR]) to 60 min (75% of maximum HR). HR was also estimated by Karonen's formula. Furthermore, every session included 10–15 min of stretching and flexibility exercises for warm up and 10–15 min for cool down.

Target HR = ([max HR − resting HR] × % intensity) + resting HR.

Strength training program

Participants were taught the correct techniques before starting the training. The training program began 2 days a week in the 1st month and continued three nonconsecutive days a week. The training intensity was 60% one repetition maximum during thefirst 2 weeks of training and increased to 75%–80% one repetition maximum. Number of sets was 1–2 sets during the 1st month. The program included 10 strength movements for the lower and upper body muscle groups. Participants performed 3 sets of 8–10 repetitions (90–120 s rest between sets). Special strength exercises include bench press, seated row, shoulder press, chest press, lateral pull-down, abdominal crunches, leg press, leg extension, triceps pushdown, and seated bicep curls. Furthermore, every session included 10–15 min of stretching and flexibility exercises for warm up and 10–15 min for cool down.

Combined training program

Participants performed aerobic training along with strength training 3 days a week. They used treadmill 20–30 min in training sessions and then performed 2 sets of 8 strength movements with 8–10 repetitions. Furthermore, every session included 10–15 min of stretching and flexibility exercises for warm up and 10–15 min for cool down.

Measurement of study variables

Participants' height and weight were recorded using a medical scale with stadiometer (Seca: 220, Germany). To measure body composition, body composition analyzer (Inbody version 3.0 made in South Korea) was used. Participants stand on device with minimum coverage and without any metals and hold device's electrodes. Participants should be smooth and without choking and head toward the front during the measurement. Time performing the measurement was the same for everyone and after at least 3 h of their meals (breakfast). All participants met considerations related to the execution of tests, including emptying bladder and intestines and not eating or drinking before the test. The reliability of the device has been declared between 1 and 0.98 in previous studies. The validity of the device to measure body composition is 98%. Blood samples were collected after 12 h fasting at pretest and 48 h after the last training session at posttest. Blood samples (10 cc) were taken from left hand in sitting position. ICAM-1 and VCAM-1 were assayed by EIA commercial kit (R and D System Co., Abington, UK). Pars Azmoon kit (Pars Azmoon Co., Tehran, Iran) was used to measure CRP levels.

Statistical procedures

Statistical analysis was performed using SPSS for Windows software, version 18 (SPSS Inc., Chicago, IL, USA). Data normality was determined by Kolmogorov–Smirnov test. Paired t-test was used for within-group comparison and one-way analysis of variance (ANOVA) was used for between-groups comparison. Tukey's test was used to determine the difference between groups. P ≤ 0.05 was.

Results

Table 1 indicates the comparison of variables between groups before and after the interference. Findings indicated that body weight in aerobic and combined training had a significant decrease (P = 0.003 and P = 0.006, respectively). BMI values in aerobic and combined training were significantly lower than (P = 0.007 and P = 0.001, respectively). Levels of fat percentage were significantly reduced in all three groups (P = 0.001, P = 0.005, and P = 0.009, respectively). Amounts of fat-free mass in strength training and combined training was statistically significant (P = 0.001 and P = 0.001, respectively).

Table 1

Comparison of before (pre) and after (post) intervention value of measured variables

ICAM-1 levels were only significantly lower in the combined training (P = 0.004). VCAM-1 levels were significantly different in strength and combined training in posttest with regard to pretest (P = 0.006 and P = 0.005, respectively). Finally, CRP levels in only aerobic training were significantly different in posttest compared to pretest (P = 0.008).

Comparison of within-group variable changes following 12 weeks is shown in Table 2. The results showed that the amount of body weight, BMI, fat percentage, and fat-free mass were significantly different within the four groups (P = 0.003, P = 0.001, P = 0.003, and P = 0.001, respectively).

Table 2

Comparison of changes in measured variables following 12 weeks in four groups

The results of Tukey's test are presented in Table 3 to compare the significance of ANOVA. Significant differences in body weight between aerobic and strength training (P = 0.004), and aerobic and control groups (P = 0.018), BMI between strength and combined training (P = 0.004) and combined and control groups (P = 0.001), body fat percentage between aerobic and control groups (P = 0.017) and combined and control groups (P = 0.004), and finally fat-free mass between aerobic and strength training (P = 0.024), aerobic and combined training (P = 0.0001), strength and control groups (P = 0.035), and combined and control groups (P = 0.0001) were observed.

Table 3

Resulted of Tukey's post hoc test for significant analysis of variance

Discussion

Various studies have indicated that aerobic, strength, and combined training cause small-to-moderate beneficial effects on body composition, ICAM-1, VCAM-1, and CRP in sedentary middle-aged men. Furthermore, few studies have confirmed the beneficial effect of combining aerobic and strength training.

According to the present study findings, body weight in aerobic and combined training decreased significantly in posttest compared to pretest. Furthermore, significant differences in body weight between aerobic and combined compared to strength groups and aerobic compared to combined training were observed after 12 weeks. Donges et al. examined the effect of 12 weeks of strength, aerobic, and combined training on body composition of sedentary middle-aged men and observed significant improvements in body weight values.[33] Ferrara et al. examined the effects of 6 months of aerobic and strength exercise on middle-aged men, and a significant decrease was observed in body weight in aerobic and strength exercise groups.[34] To maintain one's ideal body weight, the energy intake needs to be equal to the energy output, which is called energy balance and disturbing energy balance can cause over or under normal weight. It seems that exercising plays a critical role in controlling body weight. It is recommended to consider duration, intensity, and type of exercise training to lose weight.[35] Although both aerobic and combined training exercises resulted in decreased body weight, aerobic training led to better results in losing weight. Possibly, participants' participation in strength and combined training has resulted in increased fat-free mass; however, in aerobic training, only the fat percentage has decreased. Hence, aerobic training has shown better results in improving total body weight compared to other groups participating in the study.

BMI in aerobic and combined training has significantly decreased in posttest compared to pretest. In addition, a significant difference in BMI between aerobic and combined training, aerobic and control groups, and strength and combined training was observed after 12 weeks. Ho et al. investigated the effect of combined aerobic and strength training on BMI values in middle-age men and women and observed a significant decrease after 12 weeks.[36] Bijeh et al. examined the effects of 6-month aerobic exercise on middle-aged women and observed significant changes in BMI values in these participants.[37] BMI is used to classify individuals based on normal weight, overweight, and obesity worldwide, increases when one grows older, and is associated with sex and ethnicity.[36] Values for BMI are influenced by both body fat percentage and lean body mass, and since body fat percentage decreased significantly in all three groups, lean body mass was also decreased; of course, aerobic and combined training led to better results because of further reduction in BMI values.

Body fat percentage decreased significantly in all three training groups in posttest compared to pretest. The aerobic and control group had a significant difference in body fat percentage after 12 weeks. Donges et al. investigated the effect of 12 weeks of strength, aerobic, and combined training on sedentary middle-aged men's body composition and observed significant improvements in the amounts of body fat percentage.[33] Willis et al. examined the effect of 3-month aerobic and strength training on the values of body fat percentage in sedentary adult participants and only a significant decrease was observed in combined exercise group.[38] Alteration in body composition is age related and has a strong genetic predisposition. It is also influenced by environmental factors such as nutrition, disease, and physical activity and changes along with age, especially in men. Weight gain has been commonly observed at the age of 20–50 and is accompanied by gains in adipose tissue. During middle-aged individuals, the increase in adipose tissue distribution happens along with an increase in central abdominal sites and a decrease in limbs' fat. Changes in body composition depend on type, intensity, and length of exercise training.[939] Participating in exercise training will not only decrease body fat percentage but also can induce favorable effects on health.

Fat-free mass in strength and combined training increased significantly in posttest compared to pretest. Furthermore, significant differences were observed in fat-free mass between aerobic and strength, strength and control, combined and aerobic, and combined and control training after 12 weeks. Willis et al. examined the effect of 3-month aerobic and strength training on lean body mass values in sedentary adult participants. They observed a significant increase in the aerobic exercise group, unchanged in strength training, and a significant increase in combined group.[38] Strength training led to more improvements in body composition and had a more appropriate role in improving body composition compared to aerobic training.[33] It seems that combined aerobic and strength training programs have more favorable effects on body composition.

ICAM-1 levels were decreased in all three groups, but only in combined training, it was significantly lowered in posttest compared to pretest. In addition, there was no significant difference between groups. Zoppini et al. reported reduced ICAM-1 levels after 6 months of training twice a week.[40] Olson et al. investigated the effect of strength training on middle-aged overweight women and did not observe a significant reduction in ICAM-1 levels.[22] Regular exercise prevents the releasing of inflammatory mediators from adipose tissue by reducing sympathetic stimulation and increasing anti-inflammatory cytokine and consequently reduces the concentration of attaching cell molecules.[41] Another mechanism in reducing the inflammatory marker of ICAM-1 might be the antioxidation effect of aerobic training. Oxygen-free radicals cause the increased expression of inflammatory mediators and attaching cell molecules. In addition, studies have shown that the antioxidative defense will improve by exercise training.[42] Exercise training may reduce sICAM-1 levels by improving antioxidative system.

VCAM-1 levels in the strength and combined training were significantly different in posttest compared to pretest. Furthermore, there was no significant difference between groups participating in the study. Rankovic et al. examined the effect of aerobic training on VCAM-1 levels in middle-aged individuals and observed a significant decrease. The results are consistent with the results of the present study.[21] Sabatier et al. observed a significant decrease in the levels of VCAM-1after 14 weeks of aerobic training in healthy individuals. It has been shown that increased anti-inflammatory cytokine will prevent inflammatory agents release from adipose tissue, resulting in reduced attaching molecules levels. On the other hand, since cortisol acts as a strong anti-inflammatory agent in preventing cytokines secretion and anti-inflammatory mechanisms and since physical training often stimulates cortisol during exercise, perhaps exercise causes cortisol secretion and increases antioxidant capacity.[43] Finally, the mechanism related to these factors is probably the main factor of decreased VCAM-1.

CRP levels in aerobic training decreased significantly in posttest compared to pretest. Furthermore, there was no significant difference between groups participating in the study. Libardi et al. investigated the effect of strength, endurance, and combined training on CRP levels in middle-aged men and did not observe statistically significant difference before and after training.[27] Olson et al. investigated the effects of strength training in middle-aged women and observed significant improvements in CRP levels. Exercise training has beneficial effects on prevention and treatment of CVD.[22] Exercise training has indirect positive effects on cardiovascular system through a variety of mechanisms such as increased blood volume, decreased viscosity, increased stroke volume, decreased blood pressure, elevated antioxidant defense, and altered blood lipids. On the other hand, according to anti-inflammatory effects of exercise training and its role in reducing inflammatory markers, it can be a suitable solution against inflammatory agents and CVD risk factors. One of the mechanisms of inflammation is producing cytokines such as IL-6 and tumor necrosis factor alpha and consequently increasing CRP values.[27]

Conclusions

Population, sample size, nutrition, lack of physical activity control out of training sessions, and sleep and psychological states were limitations of the present study. The results showed that 12-week workout, 20–60 min/session, and 3 days a week of moderate intensity exercise improves body composition, ICAM-1, VCAM-1, and CRP than those who did not participate in any training. However, all three types of exercises had small benefits on body composition, ICAM-1, VCAM-1, and CRP in sedentary middle-aged men, and the importance of combining these types of training required further investigations. According to the results of this study, combined moderate-intensity exercise is recommended to prevent CVD and improve general health in sedentary middle-aged people. However, further studies are needed to control other mechanisms in various exercises.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.