Influence of Exercise on Anthropometric Indicators of Cardiovascular Risk in Elderly Women

The Brazilian population follows an international trend of increased aging rate driven by a decline in fertility and mortality, in addition to increased life expectancy. In Brazil alone, there are more than 15 million elderly people1. Porto Alegre is the second Brazilian capital with the highest proportion of elderly people, second only to Rio de Janeiro2. This demographic transition brings increased prevalence of non-transmissible chronic diseases (NTCDs) and, consequently, an increase in mortality from these diseases3.


Introduction
The Brazilian population follows an international trend of increased aging rate driven by a decline in fertility and mortality, in addition to increased life expectancy.In Brazil alone, there are more than 15 million elderly people 1 .Porto Alegre is the second Brazilian capital with the highest proportion of elderly people, second only to Rio de Janeiro 2 .This demographic transition brings increased prevalence of non-transmissible chronic diseases (NTCDs) and, consequently, an increase in mortality from these diseases 3 .
In Brazil and in other countries, cardiovascular (CV) diseases are the leading cause of morbidity and mortality 4 .These include ischemic heart disease, acute myocardial infarction, coronary artery disease and systemic hypertension 5 .In Brazil, morbidity of CVD is even greater in people with low income 6 .
The rapid increase in the prevalence of CVD in the end of the last century caused an alarming socio-economic scenario to be administered by governments and the private sector, significantly increasing expenses to cover treatment for these diseases 7 .Mitigation of this problem depends on the development of global strategies for the prevention of CVD and health promotion 8 .Evaluation of cardiovascular (CV) risk is of great importance for the early detection and timely treatment of CVD 9 and also to provide support for more effective planning of public policies aimed at population health.
Traditional models for CV risk prediction consider the main risk factors: age, sex, blood pressure, smoking, history of diabetes mellitus and lipid profile 9 .However, in primary care, this evaluation is not often feasible because of the difficulty in determining blood markers, whether because of delays in having the tests done or lack of resources to have the tests done.The use of anthropometric variables associated with other indicators available, routinely evaluated by primary care professionals 10 .
The measurement of skin folds is commonly used to estimate body fat percentage 11 .Body mass index (BMI) is the most studied and affordable variable.Although it is a general measure of obesity, BMI is considered strong indicator of mortality 12 .Measures related to abdominal fat, waist circumference (WC) and abdominal circumference (AC), waist/hip ratios (WHR) and abdomen/hip ratio (AHR) have presented stronger associations with CVD than BMI, especially in women [13][14][15] .More recently, a new mortality risk indicator developed, the body shape index (BSI), which considers waist circumference, BMI and height 16 .This indicator was more accurate than the other ones in the prediction of cardiovascular risk in older people (55-79 years) 17 .
The main form of intervention in health promotion and CVD prevention is based on changes in people's lifestyle.Increase in physical activity at leisure time is among the priorities in the strategic action plans on the global 18 and nacionais 19 levels to face NTCD.High levels of physical fitness are associated with decreased incidence of CVD [20][21][22] .
For elderly adults, it is recommended generally to perform moderate physical activity for at least 30 minutes daily, as well as intense physical activities two to three times per week 23 .Community programs of physical exercise are important for maintaining the health and quality of life of older people.However, in most cases, these programs only focus on socialization, not considering any biological aspects associated with the individual's functional capacity.Furthermore, regular control of exercise intensity and volume as well as individualization of overload are typically neglected.Ideally, global physical exercise programs should focus on different motor qualities in the same session of exercises 24 .
There is a lack of studies evaluating the effectiveness of community exercise

Methods
The sample in this study was composed of two groups of elderly women aged ≥60, all living in Porto Alegre, RS.The first group comprised the elderly women selected

Statistical treatment
For the statistical treatment of the data, the groups

Results
Table 1 shows the results of anthropometric indicators of CV risk among EMIPOA and PEG groups.In the 60-69 years stratum, PEG presented significantly lower values than EMIPOA for: body mass, BMI, abdominal circumference, waist circumference, AHR, WHR and BSI.
There was no difference for the following variables: height, sum of skinfolds and body fat percentage.As for the stratum 70-79, a significant difference was only found for height.PEG was, on average, 4 cm higher than EMIPOA.
Except for fat percentage and sum of skinfolds, the other variables showed a statistically significant difference, at least in one of the strata, the largest number of differences was found in the stratum 60-69 years.

Discussion
In order to compare the levels of anthropometric CV health indicators of elderly female practitioners and nonpractitioners of physical exercise, it was found that not all variables analyzed showed the expected behavior.
PEG in the stratum 60-69 years presented lower body mass values, consistent with the findings of other studies 26 .Literature shows that elderly practitioners of physical exercises should have body mass lower than non-practitioners, or at least an attenuation of its increase related to aging 27 .
As for height, no significant differences among the groups was expected, because it is a genetically influenced variable.However, PEG (70-79 years) presented significantly higher values than EMIPOA.Although the actual influence of lifestyle in reducing the height of elderly individuals is not yet known, Sagiv et al. 28 found that the regular practice of moderate to intense resistance exercise over life is associated with attenuation of loss of height resulting from aging.This attenuation appears to be due to the maintenance of bone density and intervertebral spaces 28 or potentially greater trunk flexibility in the elderly individuals who do physical exercises, thus giving them a more verticalized 29 posture.
As for BMI, it was found that physical exercise may apparently have contributed to a slight decrease of this variable, but this is only significant for elderly women aged 60-69 years.Koster et al. 26 have reported an inverse relationship between the level of physical fitness and BMI in elderly women.
Aging produces changes in body composition, even when there is no concomitant changes in body mass and/or BMI 30 .Accumulation of body fat (% fat and sum of skinfolds) related to aging is more associated with lifestyle and level of physical activity than aging itself 31,32 .
Several authors argue that physically active people have lower amounts of body fat 26,30 .However, the fact that no significant differences have been found suggests a potential inadequacy of the exercise program conducted.It would be necessary that the program generated a higher weekly calorie expenditure to achieve effective impact on variables related to body fat.
The evaluation method may also have influenced the results related to body fat.The skinfolds may not have been sensitive enough to detect differences between groups, which is related to body fat redistribution 11 .With aging, there is a significant redistribution of subcutaneous fat to ectopic deposits 33 .
Redistribution of body fat directly influences the values of some CV health indicators, from AHR to WHR, as they are related to fat accumulation in the central intraabdominal region 11 .Both for abdominal and waist circumferences and for AHR and WHR, the PEG presented lower values.As for these variables, the literature lacks cross-sectional studies that have evaluated the association between them and the level of physical activity or regular exercising.However, some studies have shown reduction in waist circumference values, WHR and intra-abdominal fat after physical training 30 .
Reflecting the results for waist circumference and BMI, BSI presented the same behavior.Significantly lower values for the PEG compared to EMIPOA.This is an important finding, since this variable has been more specific than the other anthropometric variables in CV risk stratification in elderly women 17 .
The significant difference in cardiovascular risk indicators found between the groups in the stratum of 60-69 years, pointed to some possible hypotheses.The first is related to potential reduction of trainability with aging.Older individuals would have a lower trainability, i.e., it would be more difficult to improve fitness or functionality for the same relative stimulus of training.This hypothesis seems consistent with the fact that there is a reduction in the adaptive capacity of the tissues and systems to stimuli with aging.Evidence is still lacking, and this issue is still controversial in the literature.Few studies have demonstrated a reduction in trainability 34,35 , while others showed no significant differences between old and young individuals in relation to trainability 36 .
In describing the general adaptation theory, Selye 37 points to the need for stimulus to be given in an optimal intensity range for promoting adaptation, because, being too below standard, stimulus would be weak and would not promote adaptation.Being suboptimal, some stimulus could, at the most, promote the maintenance of capacity, but without any significant improvement in performance.If stimulus is very strong, above this optimal range, it could lead to injury or adverse effects.It is believed that this optimal range should decrease with age and with other limiting factors of performance, such as pathological conditions 38 , in which there would be a relative increase of this threshold to promote adaptation, and a reduction of this maximum threshold to avoid injury or adverse effects.In addition, elderly individuals would require a longer time to undergo adaptation to physical exercise compared to younger individuals, that is, the results would take longer to be noticed 36,39 .The elderly would require higher relative intensities 30 and higher frequency of training 39 than younger individuals.
A second hypothesis is that added to this scenario, physical education teachers usually tend to be too careful with older people, who are usually more debilitated, mainly due to fear of the risk of complications arising from exercising loads.This behavior would reduce more significantly the relative intensity of training, making it even harder to obtain some positive physiological effect arising from exercising.Based on these assumptions, it is suggested, in this case, that older individuals have an even stronger training control, considering the greater difficulty of promoting positive adaptations on these individuals.
These population-based studies often establish comparisons between a sample and populations with different biopsychosocial characteristics 40 .This may generate bias in the interpretation of parameters for the classification of the population.From this perspective, this study brings a difference when comparing a group (PEG) with data from a local population living in the same region (EMIPOA).
It is important to consider that this study presents a cross-sectional design rather than a quasi-experimental design with a control group and an intervention group, which limits the conclusions and potential inference of the results obtained.The assumptions made to try to explain the lack of differences in the stratum 70-79 years between the groups still need more evidence.This fact should be considered as a gap in the corpus of knowledge of exercise prescription, but the hypotheses presented serve as a starting point to new studies that seek to give scientific support to these theories, which must provide appropriate experimental designs and study the influence of aging and senescence on trainability.

Conclusions
The findings suggest that a structured exercise program can improve the CV health indicators of participants, but the elderly of this study showed no fully satisfactory results.A review of the program is needed so they can achieve the desired results, especially with regard to the effectiveness of physical exercises for individuals older than 69.Greater care in controlling training intensity and volume of the elderly is suggested, especially with advancing age.

Potential Conflicts of Interest
This study has no relevant conflicts of interest.

Sources of Funding
This study had no external funding sources.

Academic Association
This study is not associated with any graduate programs.
programs in reducing CVD risk indicators.Deeper understanding of possible morphological changes, resulting from a regular program of exercise can, above all, serve as a basis for more effective training structuring.The objective of this study was to compare the levels of anthropometric CV health indicators (BMI, body fat, AHR, WHR and BSI) of older practitioners and nonpractitioners of physical exercises.
for the Porto Alegre Multidimensional Study on Elderly Women (EMIPOA), a population-based survey conducted by the Institute of Geriatrics and Gerontology from Pontifícia Universidade Católica do Rio Grande do Sul (IGG-PUCRS).The second group (PEG) comprised elderly women engaged in physical exercises in a community exercise program developed as an extension project by PUCRS.
were initially stratified by age groups (60 to 69 and 70 to 79 years).Data normality was tested from the Shapiro-Wilk test when the sample size ≤50, and the Kolmogorov-Smirnov test when >50.Then, descriptive statistics was used: mean and standard deviation or median and interquartile range.To compare the anthropometric indicators of CV risk among the groups, Student's t test was used for independent samples when the data distribution was parametric and Mann-Whitney in cases of non-parametric distribution.In all statistical tests, the significance level was α≤0.05.

Table 1 Anthropometric indicators of cardiovascular risk among elderly women practitioners (PEG) and non-practitioners of exercise (EMIPOA)
EMIPOA -group deriving from the Porto Alegre Multidimensional Study on Elderly Women; PEG -group of elderly women from a physical exercise program; BMI -body mass index; AHR -abdomen/hip ratio; WHR -waist/hip ratio; BSI -body shape index; § nonparametric variable; SD -standard deviation; β -statistical power; *significant difference (Student's t test or Mann-Whitney).