The increase in body fat is a serious and widespread problem globally. There are about 350 million obese (body mass index, BMI ≥ 30 kg/m2
) and 1 billion overweight persons (BMI ≥ 25), where ≈2.5 millions deaths are attributed to overweight/ obesity [1
]. In the Eastern Mediterranean region, the highest levels of overweight persons (BMI ≥ 25) were in Kuwait, Egypt, United Arab Emirates, Saudi Arabia, Jordan and Bahrain, where the incidence of overweight/obesity for those aged ≥ 25 years was between 74%–86% (women) and 69%–77% (men) [3
]. Unsurprisingly, in Egypt, the prevalence of hypertension (26.3% of adult population) is among the highest in the world [4
Childhood obesity is a public health concern, particularly as obesity in childhood could lead to an increased likelihood of obesity later in life [5
]. The global increase in obesity in children and adolescents could be attributed to decreased physical activity (PA), in addition to unhealthy lifestyle habits [6
]. Five out of every eight children aged 9–13 in the United States do not participate in any PA during their non-school hours, and almost one fourth do not engage in any free-time PA [8
]. Childhood obesity is associated with elevated blood pressure (BP), cholesterol, and BMI in childhood that could progress over time to adult premature cardiovascular disease (CVD) [9
]. Indeed, there were significant differences in mean systolic and diastolic blood pressure between obese and non-obese Bahraini school children (aged 12–17 years), and children who have high blood pressure could be at greater risk of becoming hypertensive adults [10
]. Because high blood pressure is important in the occurrence of coronary heart disease in adults [13
], it is essential that the association between PA and blood pressure and other health parameters in adolescents be examined [14
]. Current reports suggested that school-based PA interventions may be useful in the improvement of health parameters and lifestyle behaviours among children and adolescents which could lead to reduced CVD risk in adulthood [14
The increased trend toward adiposity among adolescents in the Eastern Mediterranean region [15
] places them at a high risk of adult obesity and its consequences in terms of chronic diseases later in life. Although the effects of adolescent obesity on blood pressure levels seem related to the accumulation of abdominal fat [19
], few studies investigated the association of PA with health parameters in adolescent pupils in the Middle East [21
]. For instance, little research has focussed on overweight/obesity among adolescent girls in the Eastern Mediterranean Region, even though studies elsewhere indicated an increasing prevalence and a growing health concern [16
]. This is despite that in adults, the increasing prevalence of obesity and overweight were related to the risk of occurrence of coronary heart disease and hypertension [11
Fortunately, obese/hypertensive adolescents can decrease their blood pressure through PA as an effective means for the prevention and treatment of obesity, hypertension and CVDs [23
]. However, there are no recent studies that investigated the association of PA with anthropometric and physiological parameters in Egyptian adolescent school children. Such evidence base is required in order to design and implement PA intervention programmes in Egyptian schools.
1.1. Aim of the Study
This study assessed the relationships between a PA programme (the intervention) and health parameters in adolescent school pupils in Egypt. The three specific objectives were:
Describe a range of anthropometric (weight, height, body mass index and body fat) and physiological (cholesterol level, systolic blood pressure, diastolic blood pressure and heart rate) parameters of a sample of Egyptian secondary school pupils;
Assess the association between the PA intervention and pupils’ anthropometric parameters; and,
Explore the association between the PA intervention and pupils’ physiological parameters.
The PA intervention employed in the current study comprised 60 minutes, three times per week for three months. A criterion for participating in the PA intervention was that all pupils had to regularly attend the sessions and complete the period of the 3 months PA programme. Although the total amount of the intervention’s PA added up to 180 minutes per week (3 days × 60 minutes), which is slightly higher than the guideline recommendation of 150 minutes of moderate-intensity aerobic PA or 75 minutes of high-intensity aerobic PA per week to control weight [8
], however we found mostly significant improvements in the parameters that were examined amongst the intervention pupils when compared to the controls who did not participate in the intervention. Starting with two very similar groups of pupils at baseline, three months later, the control group had deteriorated on all seven parameters while the intervention group had improved on all of them.
Risk factors associated with CVD (obesity, high percentage body fat, hypertension and cholesterol) set up themselves throughout childhood and could project into adulthood [45
]. Many adolescents place their health at risk through lifestyles that comprise insufficient PA thus resulting in a high prevalence of obesity [47
]. Certainly the overweight and obesity epidemic is spreading throughout the industrialised world with negative health effects, where for instance ≈55% of adult Americans reported a BMI > 25 kg/m2
]. These alarming trends are becoming evident in developing countries and could lead to high obesity levels in such countries if health risk behaviours continue. Indeed, the prevalence of obesity in Egypt is similar to that of developed nations (e.g., USA) [49
]. The current study assessed the association of a PA programme on anthropometric and physiological parameters (weight, height, BMI, body fat, cholesterol, SBP, DBP and HR) in a sample of Egyptian adolescent pupils. Our findings suggested that school-based PA interventions may be useful in enhancing the health parameters among children and adolescents. This could be in turn interpreted as reduced risk of CVD in adulthood [14
In relation to the first objective of the study, we described a range of anthropometric and physiological parameters for a sample of secondary school pupils. School-based BMI measurement is important as it is a potential approach to address obesity among youth [50
]. Objective measurement of weight and height are preferred than reported values, as overall self-reported measurements might systematically underestimate weight and BMI [51
]. Since the classification into BMI-categories using self-reported adolescents’ height and weight are not very accurate, we based our BMI calculation on objective measurements [53
Out of 160 pupils initially measured, 25% of the samples were overweight or obese at baseline (asserted by their BMI). This baseline level compared unfavourably with levels from elsewhere; ≈15% of adolescent girls in Norway, and 19% in Argentina (15–18 year old) were overweight or obese [57
]. This baseline level was also higher than the 13.4% (14–18 year olds) who were reported overweight or obese in a previous study in Egypt [58
]. Indeed, Egyptian girls’ mean BMI was higher than children of comparable ages in other Arab countries of [16
], and our sample’s mean BMI (21.28, data not presented) was slightly higher than mean BMI (19.2) of 404 pupils in Japan [59
]. Current adolescent overweight will likely lead to large future economic and health burdens, especially lost productivity from premature death and disability [60
]. Likewise, the baseline mean % body fat for our sample (22.0♂
, data not presented) was a little higher than that of 327 Brazilian adolescent pupils (18.1♂
With reference to baseline mean SBP, our sample’s values (116.9♂
, Table 1
) were slightly higher than the 107.1 mmHg reported in 2,156 Argentinean adolescents (15 to < 18 years old), but close to those of 676 adolescents in Norway (119.9 mmHg) [57
]. Similarly, our baseline mean DBP (74.3♂
, Table 1
) were slightly higher than Norway and Argentina (64 and 67 mmHg respectively). At baseline ≈16% of our sample was at risk of increased blood pressure, in comparison to Bahraini adolescents where 14% were classified as having high blood pressure [10
]. Hypertension is becoming common among Egyptians, confirmed by Galal’s [58
] findings that the prevalence of hypertension among Egyptians is very high, particularly among women. This is unsurprising given that the increasing rates of hypertension in children and adolescents could be correlated to the risk of coronary artery disease in adulthood [62
As regards to baseline mean cholesterol levels (Table 1
), our sample’s lowest (179.4♀
) and highest (186.5♂
) values were both higher than those of 13 years old pupils in Japan (170.1 mg/dl) [59
]; and also much higher than levels (137.4–141.7 mg/dl) of 327 Brazilian adolescents [61
]. Finally, in connection with the baseline mean HR, our sample’s lowest (80.5♂
) and highest (81.2♀
) values were close to those of Brazilian children aged 9–11 years (84.8 BPM in obese and 80.2 BPM in non-obese children) [63
In relation to the study’s second objective pertaining to anthropometric parameters, the comparisons of our intervention group with controls suggested a positive relationship between a moderate PA intervention and averting obesity and becoming unfit (e.g., decreased BMI and % body fat values, Table 2
). This supported proposals that PA could defend against weight gain by increased energy expenditure [64
]. Theoretically, although there is the potential for obese adolescents to lose weight and maintain their weight loss by participating in regular PA (at least one hour three times per week), it is rarely achievable to keep the weight off without participating in PA programmes [65
]. The positive and significant association between the PA intervention and decreased BMI in our sample of boys and girls is shown in Table 2
. This is in agreement with Gamble et al
]: a factor that has been consistently related to childhood BMI status is PA.
The results of the present study add to the increasing evidence that demonstrate the benefits of regular PA as a management plan for tackling obesity in adolescents. Our findings agree with others where regular PA was associated with significant reductions (improvement) in obesity [67
]. After our PA intervention, % body fat in the intervention boys was significantly lower when compared with controls after 3 months (Table 2
). Studies have reported significant improvements in % body fat following programmes that included PA [14
]. Therefore, the combination of increasing levels of PA and avoidance of gain in fat mass is likely to be a successful approach for preventing cardiovascular and metabolic disease [68
In relation to the study’s third objective (physiological parameters), we calculated BP as the mean of three consecutive measurements. This is important, as multiple BP measurements are required to suggest the risk of increased blood pressure [69
]. We found a positive association between PA intervention and the SBP and DBP values (Table 2
). Hypertension is a major public health problem worldwide [70
]. There is a positive association between BP and % body fat in adolescents [65
], supported by that during 3 months of PA, when compared to controls, our intervention pupils’ SBP and DBP decreased (SBP differences of 11.4♂
mmHg; DBP differences of 4.4♂
) respectively, along with decrease in body fat (differences of 4.3%♂
). However the decrease in % body fat in girls did not reach statistical significance (Table 2
In connection with cholesterol, by comparing the post intervention values of the intervention pupils with control pupils after 3 months (Table 2
), our findings suggested that for boys and for girls, the PA intervention was associated with decreases in cholesterol levels. These findings are in agreement with the U.S. Department of Health and Human Services [71
] that suggest that one approach for maintaining optimal cholesterol levels in children and adolescents is exercise; a low-cost, non-pharmacologic intervention available to the vast majority of children and adolescents.
As regards resting heart rate, the effects of physical exercise on HR are not unequivocal. For instance, in middle aged men, intermediate intensity exercise is associated with positive modification in HR [72
]. Conversely, few studies reported influence of physical training on HR [73
] in middle-aged people, and others similarly reported that high intensity interval training during 7 weeks did not affect heart rate in 10-year old children [73
]. In contrast with others (e.g., Gamelin et al.
]), we found an association between PA and HR for both genders. This contrast might be explained by the fact that our PA intervention was of longer duration (three, one-hour regular training sessions each week for 3 months) thus delivering about 70% more PA ‘volume’ than Gamelin et al.
] (7 weeks of three 30-min sessions), hence providing more time in order to impact on HR.
As regards the control children, there were significant increases (worsening) when compared with intervention pupils across many of their parameters after 3 months. It is possible to conceive an association between a low PA level (the ‘low level’ physical education delivery that is normally provided by the school) and the worsening anthropometric and physiological parameters in the controls. Unhealthy habits could be formed at this age regarding nutritional lifestyle and low PA levels and could contribute negatively to their anthropometrical and the physiological parameters. This suggested that in the social contexts of pupils, schools that do not adequately provide PA sufficient for health benefits might instead become effective environments for the propagation of negative lifestyles.
Regular attendance of moderate-intensity level PA could result in better anthropometric and physiological parameters in children. Various PA interventions have been implemented with different populations to examined their associations with different anthropometric, physiological, and body composition parameters [75
]. Some of this research supported our findings that moderate-intensity PA might be useful to decrease the hazard of heart disease in low active individuals [77
Perhaps a primary strategy for improving the long-term health of children and adolescents through exercise may be creating lifestyle patterns of regular PA that carry over to the adult years. Our findings are consistent with others [78
], overweight and hypertensive adolescents can reduce their blood pressure through PA, particularly if they lose weight. Such benefits of regular PA, if popularised and scaled up to be implemented as part of integrated community-wide intervention programmes, could play a major role in the eastern Mediterranean Region in helping to raise community awareness and involve people in health promotion and disease prevention [79
]. However, we assume that the lack of sport equipment at schools, as well as lack of exercise facilities and appropriate sport playgrounds could be some of the barriers to regular PA the Egyptian children. Our study suggested that an appropriately tailored PA intervention programme of sufficient duration could offer school pupils activities that interest them, and hence they would be motivated to participate. However more efforts are required in Egypt for the promotion of PA so that children and adolescents can avoid the risk factors associated with a range of non-communicable chronic diseases.
This study has limitations. It is cross sectional hence findings are associations, not causations. One school in north Egypt (Delta region) was selected for the study. The results would therefore need to be affirmed by bigger studies incorporating more schools in the other regions in Egypt in order to be adequately powered statistically. Not many schools in Egypt have both indoor and outdoor sport facilities and appropriate sport equipment facilities, hence factors such as weather and equipment may be major impediments to the pilot testing and/or expansion of this programme. Due to these factors, the generalisability of this PA programme to other schools in Egypt would need to exercise caution. The sample comprised 160 adolescents out of 450 children in the school who volunteered to participate, representing about 40% volunteer rate. We are unable to assess how those who volunteered could have been different on the measured parameters from those who did not volunteer. Due to funding constraints, other possible factors that could have contributed to our findings were not measured (e.g., diet control and/or extra ‘workouts’ that the intervention pupils who participated in the intervention PA might have undertaken). The PA intervention we employed delivered 180 minutes of PA per week, which is slightly less than the maximum 210 minutes per week recommended by some authorities [The United States Centres for Disease Control and Prevention 2001]. We undertook the blood pressure measurements on one day and not on three consecutive days, which is required for an accurate diagnosis of hypertension. Future research needs to confirm the prevalence of obesity, overweight and other health parameters in other larger and different samples in Egypt (younger children and older adolescents); to understand the barriers to and motivators/ promoters of exercise in and outside schools; and, to measure other possible confounding factors that could impact on the parameters that were measured.