Health Education Research Advance Access originally published online on October 13, 2006
Health Education Research 2007 22(4):588-598; doi:10.1093/her/cyl118
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Self-perceived weight status and exercise adequacy
Department of Political Science, School of Social Work, Michigan State Universtiy, 242 Baker Hall, East Lansing, MI 48824, USA
E-mail: jacks174{at}msu.edu
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Abstract |
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The growing prevalence of obesity and inadequate physical activity levels in the population highlight an opportunity to examine public opinion about exercise, as well as the perceived adequacy of exercise among adults. This article summarizes findings from a 2004 survey of exercise habits and beliefs among Michigan adults using bivariate and logit analysis. It examines perceptions of weight status and adequacy of exercise, illuminates public opinion regarding the importance and value of exercise as one aspect of active living and highlights some of the perceived barriers and facilitators to exercise. The results indicate that people believe that they exercise enough, but that demographic, socio-economic and attitudinal factors may be potential barriers to physical activity. It is important to establish and/or bolster individual and community support structures while also minimizing potential barriers to exercise at the individual, organizational and community levels.
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Introduction |
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Americans have been leading sedentary lifestyles. Being physically inactive is associated with poor health outcomes including obesity, hypertension, cardiovascular disease and fractures from osteoporosis. Having a moderately active lifestyle can improve sleep patterns, mood and mental health while reducing the onset of chronic health conditions and premature mortality. Being physically active simply means engaging in activity that causes small increases in breathing or heart rate (e.g. brisk walking, running, gardening, exercising). In 2001, only 10 states in the United States had at least 51% of residents meeting the recommendations for moderately intense physical activity [1]. In 2003, 23% of American adults were not physically active. Another 53% of Americans, though engaging in physical activity, were not meeting the minimum recommendations of 30 accumulated min of moderate physical activity most days of the week [1, 2].
The US Department of Health and Human Services has made it a priority to address obesity and physical inactivity levels in the population. Similarly, health professionals and public officials are working to reduce overweight/obesity levels and increase physical activity levels in Michigan. Consider the numbers. In 2002, 62.3% of Michigan adults were overweight or obese, compared with 59% of people nationwide. Similar to national figures, 21% of Michigan residents were inactive in 2003 and 53% did not meet recommended physical activity levels [1]. Despite these trends, unpublished public opinion data revealed that in 2002 
67% of Michigan adults reported having reasonably good exercise habits. In 2003, 21.5% of Michigan adults believed that they could be active 3 days a week, 35.5% believed they could be physically active 4–6 days a week and 32.7% believed that they could be physically active every day (unpublished data) [3, 4].
Michigan residents may have an overly optimistic perception of the adequacy of their physical activity. This study examines factors that might be associated with physical activity beliefs and habits. The article begins with an overview of literature on physical activity, health and perceptions of exercise adequacy and outlines the study rationale. It proceeds with a discussion of methodology and findings on exercise habits and beliefs among Michigan adults. The article highlights public opinion on the importance and value of exercise, and highlights some of the perceived barriers and facilitators to exercise. This information can help inform individual and community efforts to increase physical activity levels in the population.
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Literature review and study rationale |
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Being physically active can yield several health benefits. Just 30 accumulated min of moderate physical activity at least 5 days a week can (i) reduce incidences of depression, anxiety and numerous chronic diseases; (ii) improve concentration, mood and sleep patterns and (iii) delay death [5–9]. Sedentary individuals are two to three times more likely than physically active individuals to die prematurely [10, 11]. For individuals who have been inactive, even modest attempts at physical activity can generate potential benefits [12–16]. However, many individuals are not active enough to accrue noticeable health benefits [2, 17–20].
Physical inactivity is due in part to human nature, societal changes, convenience engineering and other technological advances. Highway systems, the proliferation of automobiles and late 20th century land-use patterns changed the nature of transportation in America [21–23]. Some communities are designed in ways that make it prohibitive and/or dangerous to walk or bicycle as a form of transportation [24, 25]. In addition, fewer people engage in heavy labor, having sedentary jobs instead. As occupational physical activity decreases, people need more leisure time physical activity like recreation and/or exercise [26, 27].
So who is active and who is not? What are some of the reasons behind physical inactivity? Males, younger adults, non-Hispanic whites, higher income individuals and people with higher levels of education are more likely than others to engage in leisure time physical activity [28–30]. Across age groups, women are less likely to get adequate physical activity, and this trend is even more pronounced for African-Americans and Hispanics [31]. Older adults are more likely to engage in regular physical activity when they are advised to do so by a doctor, have no physical limitations preventing them from being active, are not under stress and know how to exercise and believe that they are in reasonably good health [32].
Many people indicate that exercise, one form of physical activity, is an important component of being healthy and that it makes them feel good about themselves [33, 34]. However, groups vary in their perceptions of the adequacy of their own exercise habits. A study of 4140 adults in the United Kingdom found that only 43% of men and 39% of women surveyed felt they exercised enough [35]. Lack of leisure time and motivation were the major barriers for individuals who believed they did not exercise enough. However, factors associated with perceived exercise inadequacy were found to vary by demographics and socio-economic status. Lower income individuals were more likely to cite illness/disability, lack of money or lack of access to transportation as a major barrier to exercising. More affluent individuals were more likely to attribute their perceived exercise inadequacy to a lack of time or motivation. Another study found that weight status influenced African-American women's perceptions of barriers to physical activity, with overweight women more likely than others to cite lack of motivation as a barrier to regular physical activity [36].
Identifying and overcoming barriers of regular physical activity, perceived or real, for a variety of individuals including women, people of color, the elderly and low-income individuals remains an important research activity [32, 35, 37]. This study examined peoples' perception of the adequacy of their exercise based on demographics, perceived weight status and perceived personal, social and structural exercise barriers/facilitators. Individual measures of interest included gender, race, ethnicity, age, education, marital status and income. Some of the reasons people do not engage in physical activity on a regular basis include a lack of motivation, time and/or access or opportunity [37–40]. Other commonly mentioned barriers to regular physical activity include fatigue, physical illness and injury, economic costs, family/household/competing obligations, self-efficacy, nobody with whom to exercise, unsafe neighborhoods, lack of facilities and bad weather [30, 35, 41–43]. It was hypothesized that perceptions of exercise adequacy would be lower among women, non-whites, those with low-income, people with health problems and individuals with any of the following self-perceptions: overweight or lacking time, motivation or social support.
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Methods |
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Data
This study was exempt from Institutional Review Board (IRB) review because it was based on secondary analysis of data from a random-digit-dialed telephone survey of non-institutionalized, English-speaking individuals aged 18 years and over in Michigan [44]. Certification for use of the data file for secondary analysis was, however, reviewed and approved by the IRB at Michigan State University, as were human subjects' protections for the original survey. Between 1 September and 15 November 2004, trained staff interviewed 1000 Michigan residents using a standardized questionnaire. The sample design, stratification and weighting procedure for the original survey have been described elsewhere [45]; an overview follows. Consistent with strategies employed on other public opinion surveys [46],
60% of the sample was selected using list-assisted random-digit-dialing sampling procedures. The remaining 40% of the sample was selected from individuals who had participated in previous surveys and were willing to be re-interviewed. One adult from each randomly selected household was eligible to be surveyed. In households with multiple adults, one adult was randomly selected for participation. In addition to basic demographic information (Table I), the survey included a question about perceived weight status, 24 questions on exercise habits and beliefs and questions about government performance, the 2004 presidential election, concerns about terrorism and the war in Iraq. This analysis only focused on items related to prevalence of obesity and adequacy of exercise. Using computer-generated randomization and computer-assisted telephone interviewing, roughly half of the study population was asked 12 of the questions related to exercise habits and beliefs. The remaining half of the survey population was asked the other 12 questions. Based on standards established by the American Association for Public Opinion Research [47], there was 55.2% overall response rate, 15.2% refusal rate, 78.4% cooperation rate and 93.5% contact rate. To adjust for sampling biases, responses were weighted to account for multiple household phone lines, multiple household-dwelling adults and number of respondents in a county. Responses were subsequently weighted to reflect the gender, racial/ethnic, age and regional distribution of Michigan adults based on the 2000 US Census.
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Measures
There were two dependent variables of interest in this study: perception of overweight and perceived exercise adequacy. Respondents' answers to the question ‘Now thinking about yourself, currently, would you say you are underweight, at a normal weight, or overweight?’ was used to measure self-perceived weight status. This question was similar to the National Health and Nutrition Examination Survey question ‘Do you consider yourself now to be overweight, underweight, or about the right weight?’ The first dependent variable of interest, perception of overweight, was a binary measure of whether a respondent reported that they were overweight or not. It equaled 1 if the participant reported being overweight and 0 if the participant reported being underweight or at a normal weight.
The second dependent variable of interest reflected whether respondents believed that they exercised enough. In addition to demographics, a series of potential barriers to and support systems for exercise were included as independent variables. Potential barriers included time constraints, job demands, lack of social support, physical/health problems, lack of motivation/desire and lack of adequate exercise facilities. Possible facilitators for exercise included a range of social, environmental and personal support structures related to time, motivation, access and ability.
All of the responses to statements about exercise habits and related beliefs, including the second dependent variable, were measured on a four-point scale: ‘1 = strongly agree’, ‘2 = somewhat agree’, ‘3 = somewhat disagree’, ‘4 = strongly disagree’. The second dependent variable of interest, perceived exercise adequacy, was recoded as a binary variable for the logit analysis with the response: ‘0 = no, disagree’ and ‘1 = yes, agree’. Leaving the independent variables regarding exercise as a four-point Likert scale on the degree of agreement with a particular statement yielded very similar results to the logit analysis where the independent variables were reflected as a binary yes/no decision. As such, results presented were from the two-point binary scale, which was a clearer conceptual assessment of whether or not a particular variable was a factor in perceived adequacy of exercise.
Analysis
Frequencies were calculated for the variables of interest. Bivariate analysis was used for a preliminary assessment of factors associated with self-reported weight status and perceived adequacy of exercise. Logistic regression models were used to determine the effects of (i) demographics on perceived weight status, (ii) demographics and perceived weight status on perceived exercise adequacy and (iii) exercise barriers and facilitators, demographics and perceived weight status on perceived exercise adequacy. The results of the logit analysis for perceived weight status, for the full sample of 1000 adults, represented the odds of reporting being overweight compared with reporting being underweight or at normal weight.
The results of the logit analysis for the second dependent variable, perceived exercise adequacy, represented the odds of reporting exercising enough compared with not exercising enough. The 95% confidence interval (CI) and statistical significance are reported for each logistic regression. The logit analysis for exercise adequacy was based on a sample subset of 511 adults, due to computer randomization of the exercise question assignment in the original survey design and implementation. Compared with the Michigan adult population, the sample subset (see Table I) resulting from randomization of the exercise questions had a higher percentage of men, Caucasians and people with a higher median income. According to the 2000 US Census, 49% of the Michigan adult population is male, 80.2% is Caucasian, 12.3% is 65 years or over and the median household income is $44 407. The median income reported for the subset sample was in the range of $50 000–59 999; participants were asked to report income by categories, not direct amounts [48].
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Results |
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This analysis addressed three basic issues. The first was the extent to which people considered themselves overweight and what factors were associated with that perception. The second was basic habits and beliefs related to exercising, along with potential barriers and/or support structures. The third issue was the association between various factors and perceived exercise adequacy. This last component of the analysis was intended to provide insights for individual and community efforts to increase physical activity levels in the population.
Perceived weight status
When asked about their weight, 58% of people reported that they were at a normal weight, 5% reported being underweight and 37% reported being overweight; however, the survey did not include self-reported height or weight. Bivariate analysis indicated that individuals aged 50 years and over (
2 = 113.34, P < 0.01), lower income individuals (2 = 70.91, P < 0.01) and individuals who have been previously married (divorced, separated, widowed) were more likely to report being overweight (2 = 111.83, P < 0.01) than were others (not shown in table). Logit analysis clarified these findings, indicating that older individuals had 1.03 times greater odds (CI = 1.02–1.04) of reporting being overweight than did younger adults. Married individuals had 0.57 times lower odds (CI = 0.25–0.88) of reporting being overweight, and higher wage earners had 0.91 times lower odds (CI = 0.84–0.98) of reporting being overweight (Table II).
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Views on exercising: potential barriers and facilitators
The various questions regarding exercise were randomly posed to roughly half of the study participants. The percentages and odds ratios (ORs) that follow were based on those sample subsets. Over 60% of the people believed they got as much exercise as needed and nearly everyone believed that exercise improved their physical health. Over 50% of people reported they would choose exercise over alternative leisure time activities, indicating a conscious commitment to being physically active (Table III). Most people indicated that exercising (i) was a priority for them, (ii) could be fun or enjoyable and (iii) made them feel good about themselves (91, 94 and 98%, respectively). These percentages were for the individuals responding to the second subset of questions: exercising is a priority (n = 477), exercising is enjoyable (n = 475), people feel good when exercising (n = 476).
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While there could be any number of potential barriers to exercise, people were not generally willing to use them as an excuse not to exercise (see Table III). For instance, 29% of the people in the first sample subset indicated that costs and/or time constraints prohibited them from being physically active. Approximately 25% of people in this same sample subset indicated that they did not bother to exercise because it was too hard. Of the individuals in the second sample subset,
36% indicated that they had too many other obligations at home to have the time to exercise. Nearly 73% of people in the second sample subset indicated that they would exercise more if they had somebody to exercise with. It is useful to note that this group did not say that they would exercise, but rather that they would exercise more, if they had company. Neither health, a lack of knowledge, perceived weight status nor age was an adequate reason for not exercising. Less than 20% of individuals in the first subset reported having physical or health problems that would prohibit them from exercising. Similarly, <10% of people in the second subset indicated that they could not exercise because they did not know how to get started, or because they were out of shape, overweight or too old (see Table III). When it comes to potential support structures for exercising, respondents reported mixed views (see Table III). Over 80% of people in both subgroups felt that they had a safe and/or accessible outdoor area to exercise in. Approximately 40% of respondents in the second sample indicated that their workday and/or environment was not conducive to exercising on one's free time (lunch, break, before/after work), 67% of people in the first sample subset felt that they had enough time to exercise. Many people reported having the necessary social supports for exercising. In the first sample subset, 67% of respondents indicated that their doctor encouraged them to exercise and 88% reported that they had support to exercise from family and/or friends. Overall, there were adequate individual, environmental and social incentives for exercising and few barriers.
Factors associated with believing that one is getting adequate exercise
Of the 1000 survey participants, 511 were randomly asked the extent to which they agreed with the statement ‘I exercise as much as I need to’. A random number generator program linked to the computer-assisted interview script made the determination of who was asked this question. There was no selection rule for participant inclusion based on demographics or any criteria other than that imposed by the computer-generated random number program [45]. Within this subgroup, 3.9% of respondents reported that they were underweight, 53.5% indicated that they were of a normal weight and 42.6% reported being overweight. Bivariate analysis indicated that non-whites (2 = 24.20, P < 0.01), individuals aged 65 years and over (2 = 65.21, P < 0.01), people earning higher incomes (2 = 153.91, P < 0.01) and people who had been previously married (2 = 70.69, P < 0.01) were more likely than others to state that they exercise as much as they needed to. In addition, people who viewed themselves as underweight or at a normal weight (2 = 55.47, P < 0.01) were also more likely than those who saw themselves as overweight to believe that they exercise enough (not in table).
The results of the logit analysis using responses to the question about getting enough exercise as a dependent variable follow. Although race and marital status seemed to be associated with one's view on the adequacy of their exercise in the bivariate analysis, they were not found to be statistically significant factors in the logit analysis for Model 1 (race, P = 0.053; marital status, P = 0.063). When perceived exercise adequacy was regressed (logit) against demographics and self-perceived weight status, only age, income and weight status were found to be statistically significant (Table IV). Older individuals had 1.03 greater odds (CI = 1.01–1.04) of believing that they exercised enough when compared with individuals in younger age categories. Similarly, individuals with higher incomes had 1.15 greater odds (CI = 1.04–1.25) of believing that they exercise as much as needed when compared with lower income individuals. Lastly, individuals that perceived themselves to be overweight had 0.23 lower odds (CI = –0.22 to 0.68) of believing that they exercised enough when compared with those individuals who consider themselves to be underweight or of normal weight.
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There were several other factors potentially associated with one's perception of whether they exercise enough. A second logit model was run to include various barriers to and facilitators of exercise, in conjunction with weight perception and basic demographics. As noted in the earlier model, age, income and weight perception were all associated with one's perception of the adequacy of their exercise habits. The revised model indicated that marital status and education level, as well as perceived barriers and support structures, were also associated with perceived exercise adequacy (see Table IV).
Compared with others, older adults (OR = 1.03, CI = 1.01–1.05) and individuals with higher incomes (OR = 1.19, CI = 1.05–1.32) had greater odds of believing that they exercised enough. People who reported that they would choose exercise over other leisure time activities had 3.30 greater odds (CI = 2.76–3.83) of believing that they exercised enough, as did people who believed that they had enough free time to exercise (OR = 4.33, CI = 3.70–4.97). Similarly, people who had the support of family and/or friends had 3.32 greater odds (CI = 2.35–4.29) of believing that they exercised enough. On the other hand, people who had health problems or simply thought it was too hard to exercise had 0.30 lower odds of believing that they got enough exercise (CI = –0.46 to 1.06 and –0.36 to 0.97, respectively). In comparison to others, highly educated people (OR = 0.83, CI = 0.70–0.95), as well as people who were married (OR = 0.37, CI = –0.25 to 1.00) and those who thought they were overweight (OR = 0.31, CI = –0.24 to 0.86), also had lower odds of believing that they exercise enough. There was no statistically significant association between perceived exercise adequacy and either doctors' encouragement or the cost of exercising.
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Discussion |
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Results of a 2004 statewide public opinion survey indicated that Michigan adults believed that exercising was good for them and made them feel good about themselves. A majority of people believed that they had adequate exercise habits and that they were maintaining a healthy weight. Less than 40% of Michigan residents reported that they were overweight. This percentage was down slightly from similar surveys conducted in previous years. In 2002, 42.3% of Michigan adults self-reported as overweight, compared with 43.3% in 2003 (unpublished data) [3, 4]. Research has shown that people tend to inaccurately perceive their weight status [49, 50]. Thus, the self-perceived weight status noted in the current sample may not have been truly reflective of the percentage of adults that were actually overweight or obese. Michigan was ranked among the top 10 states for prevalence of obesity in the population in 2003, and has consistently posted combined overweight and obesity numbers >50% for its residents [1].
How an individual viewed his/her body likely influenced whether they believed they were doing enough to maintain it. As such, self-perceived weight status was a reasonable factor to use to investigate perceived adequacy of exercise habits, even if it was not an objective measure of weight status. Note that self-perceived weight status was not used in this study to indicate a prevalence of overweight or obesity in the population. Rather, it was used to provide an estimation of how people viewed their bodies and to investigate the association between that view and perception of the adequacy of exercise habits.
In general, people were more likely to believe that they exercised enough if they perceived themselves to be underweight or of normal weight. As expected, having the willingness, time, ability and support to exercise were key factors associated with individuals feeling like they exercised enough. Since these are all factors likely to be associated with the degree of exercise participation, it makes sense that they would be associated with perceived exercise adequacy. Being older and earning more money was also associated with people believing they were getting adequate exercise. It may be that these individuals had the time and/or money to support their exercise habits. Married people, individuals with higher education levels, those with physical or health problems, and those who believed it was too hard to exercise were all less likely to believe that they get as much exercise as needed.
At first glance, the views of highly educated people and high wage earners seem contradictory. However, it may be that highly educated people did not believe that they were getting adequate exercise because they were aware of existing recommendations for physical activity (including exercise) and knew that they were not meeting them. It may also be that even in the absence of clarity about physical activity recommendations, highly educated people simply realized that they could have been exercising more than they did.
This study is subject to several limitations. First, households without telephones were excluded from the sampling frame and therefore are not represented in the findings. Second, non-English-speaking individuals (3% of Michigan population) were not represented in the sample. Another potential limitation of this study was its reliance on self-reported weight status and adequacy of exercise. Many types of studies rely on self-reported measures [12, 51, 52], although doing so can lead to bias due to under- and over-reporting [50]. Self-reported values have been found to provide a reasonable approximation for actual values [53–55]. In addition, perceptions were at the heart of this analysis. Of particular interest was whether people believed they were getting enough exercise and what factors influenced that perception.
The findings indicate that people believe they exercise enough, but that demographic, socio-economic and attitudinal factors may be potential barriers to physical activity. Perceived weight status and demographic, social and structural factors are associated with perceived exercise adequacy. Published research has focused on a few of these factors in isolation. A contribution of this study is the focus on an association between perceived exercise adequacy and a combination of factors. It suggests that it is the intricate and joint associations between demographics, intrinsic motivation, self-efficacy, social support, and perceived barriers to exercise that matter. This highlights the value of additional research on the associations and influences of multiple factors on physical activity levels, perceived and real.
The study demonstrates the need to continue to target interventions to specific audiences that are segmented by more than just demographic factors. It is important to direct efforts to increase physical activity levels in the population, according to prevailing motivations and beliefs. It is similarly important to establish and/or bolster individual and community support structures while also minimizing potential barriers to exercise at the individual, organizational and community levels. For example, helping people find ways to make more time for exercise may be one approach to increasing physical activity levels. It will likely include many of the strategies currently underway, including increasing the availability of and access to work site exercise facilities. At a minimum, it may require showers and locker rooms so that workers can take advantage of outdoor facilities that are located en route to and from work. It may also require workplace strategies that encourage workers to be physically active during breaks.
Exercise is important regardless of its effect on weight status. It is important to enable people to act meaningfully upon this knowledge and actually increase their physical activity levels. It may be that once people truly believe that getting adequate exercise will reduce the potential for poor health outcomes and improve their quality of life, both attitudes and behaviors toward exercise will change. There is value in continuing health promotion campaigns and other efforts to increase physical activity levels in the population. This could include paying attention to community design and other potential barriers to and facilitators for physical activity. The need for and opportunity to undertake empirically based actions to reduce barriers and/or increase support systems for exercise in the individual, organizational, community and policy domains remains a key priority in achieving active living across the life span for all types of people. The growing prevalence of obesity and inadequate physical activity levels in the population highlight the public health relevance and potential impact of this research.
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Conflict of interest statement |
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None declared.
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References |
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Received on August 18, 2005; accepted on August 24, 2006
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