1. Introduction

Physical activity plays a significant role in an individual’s physical and mental health. As Professor Jeremy Morris stated over 25 years ago, the World Health Organization’s guidelines (2020) emphasize that investment in physical activity (PA) remains the “best buy” for public health [1]. Recent estimates indicate that supporting individuals to engage in more physical activity could prevent approximately 3.5 million global deaths annually [2]. According to available evidence, physical inactivity is identified as the fourth leading global cause of mortality (6% of all deaths), and insufficient activity is estimated to be the primary cause of 21–25% of breast and colon cancer cases, 27% of diabetes cases, and nearly 30% of the burden of ischemic heart diseases [3]. In other words, approximately 75% of healthcare costs are attributed to chronic diseases resulting from unhealthy behaviors such as tobacco use and exposure, malnutrition and food insecurity, and physical inactivity [4]. Based on existing definitions, any type of bodily movement created by skeletal muscles that requires energy expenditure is considered “physical activity.” Physical activity is a multidimensional behavior and does not occur in vacuum conditions, so its definition should encompass several related structures such as sedentary behavior, energy expenditure, and physical readiness [5].

Based on “Global Strategy on Diet, Physical Activity, and Health”, “physical activity” was identified as a key determinant of overall energy expenditure, serving as the basis for energy balance and weight control [6]. Despite the proven role and importance of physical activity in promoting optimal health throughout one’s life [7], study results indicate that in the United States, only one in five adults engaged in an acceptable level of physical activity [8], and the awareness of individuals about the existence of government guidelines for physical activity in 2008 was 36.1%, with only 1% having knowledge about the guidelines for engaging in moderate-intensity physical activity [9]. In Iran, physical inactivity is prevalent, especially among women and the elderly. This issue is so serious that 40% of Iranian adults (31% of men and 48% of women) are classified as insufficiently active.

Self-report questionnaires, interviews, and objective tools such as pedometers and accelerometers are used to assess individuals’ levels of physical activity [10]. However, health guidelines and disease-related recommendations regarding physical activity are based on data reported by individuals themselves rather than by tools and devices [11]. However, the results of some studies have shown that self-report methods do not show an accurate estimate of the absolute values of physical activity, and there is limited empirical evidence in this regard [12]. During reproductive years, the conditions of being overweight and physical activity differ and require increased attention, as women are at a greater risk for weight gain and obesity during this period. Women aged 18 to 50 have a higher likelihood of gaining weight compared to women over the age of 50 [13]. The reproductive period, which includes the time before, during, and after childbirth, is a crucial phase that is associated with weight gain and fat accumulation in mothers [14]. The importance of this issue is highlighted by the fact that after childbirth, women, on average, experience an increase in weight of 500 to 3000 grams [15]. The appropriate weight of a mother during this period is significant because having excess weight and obesity prior to and during pregnancy can increase maternal-related complications and unfavorable outcomes during delivery [16]. Findings from a study conducted by Awoke and colleagues regarding physical activity levels during the reproductive period indicate that physical activity among women significantly decreases during pregnancy. Accordingly, the percentage of women adhering to physical activity guidelines (total activity in minutes) among pregnant women (31.0%) was lower than that of women before pregnancy (59.4%) and women after childbirth (48.8%) [17]. Additionally, other studies have shown that 80% of pregnant women engage in insufficient physical activity, and this situation persists even after childbirth [18]. Given that being overweight among women is often viewed as a major concern for their health or body image, increasing physical activity, along with reducing caloric intake, is often recommended to help women lose weight [19]. In many global studies and those conducted in Iran, the age range of middle-aged women has been considered to be between 30 and 50 years. The findings also revealed that 12.2% of women were in a menopausal state [20]. The results of a study conducted by Ranjbar and colleagues on 17,178 Iranian women aged 20–40 also indicated that, on average, there is a gap of 15.4 ± 0.2 months between marriage and the first pregnancy for women [21]. Findings from studies conducted in Iran by Golshiri and colleagues on 960 women in menopause regarding menopause-related factors indicated that the average age of natural menopause among the studied Iranian women was 48.66 ± 3.79 years [22]. Considering the likelihood of menopause in women—as a confounding variable—and taking into account the results of the mentioned studies, this research focused on three 5-year age groups, specifically women aged 30 to 45, as the target age group. Therefore, considering the prevailing social and cultural conditions in Iran, this study was conducted with the aim of examining and comparing the physical activity of middle Age women (30–45 years), using both self-reporting and pedometer-based methods, as well as exploring related components.

2. Materials and methods

Preliminary data were obtained from a study based on Self-Determination Theory (SDT) in the community context regarding physical activity among women aged 30–45 years covered by Semnan University of Medical Sciences, Iran. The methodology and full details of the mentioned protocol have been published elsewhere [23].

3. Results

The mean age of the women participating in this study was 27.4 ± 2.36 years. 82.6% of the women were married, and on average, there were 18 children per 10 women. 46.7% of the women had university education, and only 9.23% of them had administrative jobs. 43.7% of them were members of social networks (such as mosques, organizations, or public interest groups), and 64% had access to parks and green spaces. In this study, the number of aerobic steps, total steps, and related components were examined and compared (Table 1).

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Table 1. Physical activity of participants separated by demographic and background variables.

https://doi.org/10.1371/journal.pone.0319288.t001

The values obtained from the assessment of women’s physical activity by pedometer were compared with the WHO’s recommended values. The findings of this study indicated that a total of 94.5% of the examined women were inactive or had insufficient physical activity. The data on physical activity reported by self-assessment and measured by pedometer/accelerometer were compared. Out of the 91 women participating in the study, only 60 accurately reported their physical activity. Based on the data collected on physical activity through self-reporting, only 11.7% of women classified themselves as having “low activity,” and in 3.88% of cases, they reported their physical activity level as “sufficiently active.” (Table 2).

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Table 2. Physical activity of participants measured using self-reported data and pedometer.

https://doi.org/10.1371/journal.pone.0319288.t002

There was no correlation observed between the amount of physical activity reported by the women and the number of steps measured by the pedometer; in other words, the women did not accurately estimate their physical activity levels (r = 0.037, p = 0.779) (Table 3).

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Table 3. Correlation observed between self-reported and pedometer.

https://doi.org/10.1371/journal.pone.0319288.t003

The physical activity measured by the pedometer was analyzed based on each of the demographic and social components. There was almost no significant relationship observed between most of the mentioned components and the level of physical activity of women, except for a significant relationship between the number of children and the level of physical activity (p-value = 0.035), it was found that women with children engaged in a higher level of physical activity compare to those without children (Table 1). The relationship between the number of children and physical activity was examined while considering Bonferroni correction and the significance level (0.017 at α = 0.05). A significant relationship was found between the number of children and physical activity (p-value = 0.011) (Table 1).

4. Discussion

Based on the self-reported data in this study, only 11.7% of the women in the study identified themselves as “sedentary or low-active,” but by measuring the steps recorded by pedometers, it was found that 94.5% of women in the “sedentary and low-active” group met the recommended number of steps by the World Health Organization [28]. The results of the upcoming studies are largely similar to the findings of the study by Mohamad Hasnan Ahmad and colleagues. In their study, all 169 women participating in the research were classified into the active group based on self-reported data, whereas only 8.4% of those same women were categorized as having sufficient physical activity based on the data recorded by the pedometer. Another similarity between the two studies is that women used the pedometer for one week. However, in our study, the pedometer was provided to all women, while in the aforementioned study, only 63.3% of the women used the pedometer [29]. In a study conducted by Jahan and colleagues, it was also found that in self-reporting method, only 55% of women and 44% of middle-aged men considered themselves as low-active. However, in self-reported data or step counts measured by pedometers, it was revealed that 80% of respondents were low-active and the number of women exceeded that of men [30]. In a study conducted in Rasht, it was also found that only 28.4% of women engaged in vigorous physical activity [31], although in the present study, the intensity of physical activity was not the focus of the researchers. The components related to physical activity were not examined in the mentioned study, and since the comparison of step counts in men was not the focus of our study, we are unable to make comparisons in this regard. The findings of this research align to a large extent with the results of the study by Hosseini and colleagues, who reported insufficient physical activity in 75% of middle-aged women in a consistent manner [32]. Furthermore, the results of the present study show some similarities with the findings of another study that reported a 69% rate of physical inactivity among women in Ardabil [33]. Based on the studied components, this research only observed a significant relationship between the number of children and the level of physical activity. However, in a study conducted by Hosseini and colleagues, an inverse relationship was reported between the age of women and the duration of intense and moderate physical activity, and a direct relationship was reported between the individual’s level of education and the duration of intense and moderate physical activity [32]. The results of studies conducted in other cities in Iran (such as Rasht) also indicate that only 28.4% of women engage in intense physical activity [31]. Looking at the results of studies in other regions of the world, a more favorable situation is not observed, with rates of physical inactivity in Europe reported to be between 43.3% and 87.8% [34], and up to 80% of American adults are also reported to be in an undesirable state in terms of physical activity [35]. Referring to the findings of the present study and similar cases, it becomes evident that participants in such studies tend to self-report more physical activity. The results of this investigation align with a study conducted by Murphy and colleagues, which aimed to examine the validity and reliability of three methods for assessing and reporting physical activity among students.

The study by Murphy revealed weak to moderate correlations (r =  0.29–0.37, p < 0.01) between self-reported moderate to vigorous physical activity (MVPA) levels and accelerometer data in terms of minutes per day of physical activity, and these correlations (r = 0.29–0.47, p < 0.01) were particularly significant for women [36]. Overestimation of the number of steps reported by women participating in this study showed similarities with the findings of the study by Ekalak. In the study by Ekalak and colleagues, it was also found that self-reported physical activity results may lead to inaccurate determination of physical activity levels and may bias the relationship between physical activity and outcomes of interest [37]. Although the research by Joseph and colleagues identified family and caregiving responsibilities as one of the barriers to women’s participation in physical activities, it was noted that individuals without children have more leisure time compared to women with children [38], our study findings clearly indicate a significant relationship between having children and the number of steps taken by an individual, such that having children motivates individuals to engage in more physical activity. However, further evidence and reasons regarding this matter were not examined.

In the study conducted by Jahan and colleagues, the relationship between daily physical activity (measured as steps per day using pedometers and self-reporting methods) and health indicators was examined among 145 Indian individuals (n = 76 women and n = 69 men) aged 40 to 60 years [30]. In the mentioned study, the OMRON pedometer (HJ-325), which records the number of steps taken throughout a day, was used for only 3 consecutive days. The reading and recording of the number of steps each day, as well as resetting the pedometers, were the responsibility of the participants themselves. The average number of steps per day for women was 1558 ± 3226 and for men was 2530 ± 4273. A positive and significant relationship was found between the number of steps measured by the pedometer and the self-reported physical activity (r = 0.5, p   <  0.001) [30]. However, compared to the aforementioned study, utilizing more advanced pedometers with the capability of automatically storing and transferring data via USB, which eliminates the need for individual intervention and daily manual adjustments, the measurement of step counts over a longer duration (7 days) and having a larger sample size are among the advantages of our study design. While Jahan and colleagues reported a significant correlation between the steps measured by the pedometer and the steps reported by individuals, no such correlation was observed in our study. The findings from both studies indicated that the majority of the middle-aged individuals surveyed were sedentary.

Conclusions

The complexity of the relationship between physical activity, individual health status, and social functioning has been emphasized in many studies. In many of these studies, single-axis accelerometers have been used, which are often placed on limited areas of the body such as the hip and do not assess upper body activities or restricted hip movements in activities like stationary cycling or weight lifting effectively [39], but in this study 3-axis pedometers/accelerometers with higher accuracy were utilized, which only count the number of steps taken by the individual without registering other movements. Additionally, the use of this type of pedometer, which was available in the form of a necklace and did not restrict the participants’ other activities, was well-received by the women involved in the study. Additionally, considering the potential variation in physical activity on different days of the week, researchers focused on the average number of steps taken by individuals over the course of a week. The findings of this study indicated that the assessment of physical activities based solely on questionnaires and subjective methods is unreliable and should not serve as the basis for judgment and evaluation, thereby recommending the use of objective methods. Furthermore, increasing the number of study samples from various age and gender groups is recommended. Patterns and predictors of physical activity are clearly influenced by gender and other factors, and the benefits, barriers, and psychological consequences of physical activity for women, especially in cases of communication difficulties due to issues such as urinary incontinence, depression, mood disorders, and obesity [40], are among the issues that should be considered in future studies. Although assessing individuals’ physical activity is limited by self-reporting methods and has its own constraints and ambiguities, the main challenge when comparing data collected by accelerometers and questionnaires is that these two methods measure related but dissimilar constructs. This means that accelerometers measure the accelerations of movements in physical activities, and such instruments do not directly measure an individual’s behaviour [39]. Despite the identified limitations and ambiguities, the self-reporting method for assessing physical activity continues to be utilized and is often used as a basis for judgment [41–43]. While the dose-response relationship of physical activity for preventing non-communicable diseases in healthy individuals in specific age groups has been endorsed [44], noticeable sedentary behavior and concerns of women as valuable family members on one hand, and the lack of credibility of mental and self-report methods in assessing physical activities and other health measurements on the other hand, highlight the need for changes in assessment methods and decision-making in health-related areas. Therefore, the adaptation of physical activity enhancement programs for women considering cultural backgrounds and in a more social context is necessary. Additionally, the study highlights that reliance solely on questionnaires and subjective methods for assessing physical activity is unreliable and should not serve as the basis for judgment and evaluation; thus, the use of objective assessment methods is strongly advised.

Acknowledgments

The article’s authors are grateful to all the women involved in collecting and completing the information.