The Physical Activity Guidelines for Americans, second edition provides evidence-based recommendations for physical activity participation.1 For adults, the Guidelines recommend moving more and sitting less throughout the day and acknowledge that some activity is better than none. For substantial health benefits, adults should do at least 150 to 300 minutes per week of moderate-intensity aerobic physical activity or 75 to 150 minutes per week of vigorous-intensity aerobic physical activity or an equivalent combination of moderate- and vigorous-intensity activity (henceforth, moderate-intensity equivalent activity), preferably spread throughout the week. Additional health benefits can be achieved with participation beyond 300 minutes per week of moderate-intensity equivalent activity.
The recommendations in the Guidelines suggest several levels of aerobic physical activity participation are important for public health monitoring. First, inactivity, or the lack of moderate- to vigorous-intensity physical activity, impairs health and is to be avoided. Second, insufficient activity (doing some moderate intensity equivalent physical activity but less than 150 min/wk) provides some health benefits compared with inactivity but not as many health benefits as meeting the aerobic guideline. Third, meeting the minimum aerobic guideline of at least 150 minutes per week of moderate-intensity equivalent aerobic activity provides substantial health benefits compared with inactivity. Because the health effects differ by level of participation,1 documenting how participation is changing among these categories is important for understanding the impact of physical activity levels on population health.
The Guidelines define aerobic activity as “physical activities in which people move their large muscles in a rhythmic manner for a sustained period of time”1 and include running, brisk walking, cycling, dancing, and swimming as example aerobic activities.1 Notably, the Guidelines state that the purpose of the aerobic activity does not matter; people with physically active occupations or those who walk or bicycle for transportation can count those activities toward their weekly total as long as the activities are of at least moderate intensity (eg, walking should be brisk).1 The purpose of physical activity is usually classified into 4 domains: leisure, occupational, household, and transportation (ie, domain-specific physical activity).2 Though activity in any domain counts toward meeting guidelines, public health monitoring of physical activity participation often focuses on leisure-time activities.3–5 Expanding surveillance to include all domains (ie, multidomain physical activity) may be important for accurate assessment of meeting the aerobic guidelines.6
Assessment using questionnaires (vs device-based assessment) allows respondents to provide separate estimates of activity in different domains. The National Health and Nutrition Examination Survey (NHANES) is unique among US public health surveillance systems in consistently including a multidomain questionnaire to assess aerobic physical activity participation since 2007/2008.7 A recent report by Du et al8 examined multidomain physical activity among adults in NHANES from 2007/2008 to 2015/2016 and revealed no statistically significant increases in meeting the aerobic guideline overall but reported subgroup increases among women, non-Hispanic Blacks, and adults of normal weight or with obesity. At least 2 important questions remain unanswered regarding multidomain aerobic physical activity participation among adults. First, a new cycle (2017/2018) of NHANES data is available; will the new cycle alter previous findings? Second, trend estimates for inactivity and insufficient activity have not been published; is participation changing in these categories? Answering these questions will indicate whether and how multidomain aerobic physical activity is changing among US adults.
In addition to multidomain aerobic physical activity, understanding how domain-specific activity is changing is also important. Low participation in one domain may suggest an opportunity to increase participation through targeted strategies. For example, the Guide to Community Preventive Services Task Force recommends creating activity-friendly routes to everyday destinations by combining improved pedestrian or bicycle transportation infrastructure with land use and environmental design interventions.9 Linking destinations could impact transportation-related physical activity to a greater degree than activity in other domains. Furthermore, patterns of participation by subgroup may differ across domains.6,10 For example, recent reports suggest that differences in physical activity participation across levels of educational attainment are wider when leisure-time physical activity is considered in isolation than when combined with other domains.6,10 Understanding how participation in each domain is changing over time is, therefore, important to identify opportunities for intervention and to determine whether disparities are changing.
The purpose of this article is to update and address gaps in our understanding of physical activity participation across domains among US adults by answering 2 questions. First, when examining multidomain physical activity, how has the prevalence of inactivity, insufficient activity, and meeting the aerobic guideline changed from 2007/2008 to 2017/2018 overall and by selected subgroups? Second, when examining domain-specific physical activity, how has the prevalence of inactivity, insufficient activity, and meeting the aerobic guideline changed from 2007/2008 to 2017/2018 overall and by selected subgroups?
Methods
Data Source
Detailed methods about the NHANES design, sampling, and data collection are available from the National Center for Health Statistics7 and are summarized here. NHANES is an ongoing, in-person, cross-sectional survey designed to be representative of the civilian, noninstitutionalized US population. Though data collection is continuous, data are released in 2-year cycles. This analysis covers the period of consistent multidomain physical activity assessment spanning six 2-year cycles beginning 2007/2008 through the most recently released 2017/2018 cycle. Publicly available data from these years were downloaded from the National Center for Health Statistics website.7
Physical Activity Assessment
Participants reported typical-week aerobic physical activity participation using items adapted from the Global Physical Activity Questionnaire.11 Activity was assessed in 3 sections: combined occupational and household activity, transportation-related walking and bicycling, and leisure-time physical activity (Table 1). In the NHANES assessment, occupational/household and leisure-time activity was further divided into moderate and vigorous intensity, whereas transportation was classified as moderate intensity only. When a participant answered “yes” to a prompt, they were asked about the frequency (in days per week) and duration (in minutes per day) for that domain and intensity combination. Weekly minutes were calculated as frequency multiplied by duration, and vigorous minutes were doubled to yield moderate-intensity equivalent minutes.1 Participants were classified into participation categories based on moderate-intensity equivalent minutes per week: inactive (no reported activity of at least 10 continuous minutes), insufficiently active (some activity but not enough to meet the guideline), and meeting the aerobic guideline (≥150 min/wk of moderate-intensity equivalent activity). We repeated this classification 4 times: once using moderate-intensity equivalent minutes from all domains (multidomain activity) and 3 additional times analyzing domain-specific activity (leisure-time only, occupational/household only, and transportation only). NHANES only assessed aerobic physical activity during this period, so although we acknowledge the importance of muscle-strengthening activity,1 this analysis is limited to aerobic activity only.
Physical Activity Assessment Promptsa in the NHANES, 2007/2008 to 2017/2018
| Order | Domain(s) | Intensity level | Prompt |
|---|---|---|---|
| 1 | n/a | n/a | Next I am going to ask you about the time you spend doing different types of physical activity in a typical week. |
| 2 | Combined occupational/household | Vigorous | Think first about the time you spend doing work. Think of work as the things that you have to do such as paid or unpaid work, studying or training, household chores, and yard work. Does your work involve vigorous-intensity activity that causes large increases in breathing or heart rate like carrying or lifting heavy loads, digging or construction work for at least 10 min continuously? |
| 3 | Combined occupational/household | Moderate | Does your work involve moderate-intensity activity that causes small increases in breathing or heart rate such as brisk walking or carrying light loads for at least 10 min continuously? |
| 4 | Transportation | Moderateb | The next questions exclude the physical activity of work that you have already mentioned. Now I would like to ask you about the usual way you travel to and from places. For example to work, for shopping, to school. In a typical week, do you walk or use a bicycle for at least 10 min continuously to get to and from places? |
| 5 | Leisure time | Vigorous | The next questions exclude the work and transportation activities that you have already mentioned. Now I would like to ask you about sports, fitness, and recreational activities. In a typical week, do you do any vigorous-intensity sports, fitness, or recreational activities that cause large increases in breathing or heart rate like running or basketball for at least 10 min continuously? |
| 6 | Leisure time | Moderate | In a typical week, do you do any moderate-intensity sports, fitness, or recreational activities that cause a small increase in breathing or heart rate such as brisk walking, bicycling, swimming, or golf for at least 10 min continuously? |
Abbreviation: NHANES, National Health and Nutrition Examination Survey.
aOnly the prompts are presented here. When participants answer in the affirmative, follow-up questions assess the usual frequency (in days per week) and duration (in minutes per day) of participation for each domain/intensity.
bAll transportation-related activity is assumed to be of moderate intensity in NHANES.
Stratifying Variables
Participants self-reported their gender (male and female), age (18–24, 25–34, 35–44, 45–64, and ≥65 y), and educational attainment (less than high school, high school graduate or equivalent, some college or an associate’s degree, and a college degree or higher). Participants reported their racial and ethnic group (non-Hispanic White; non-Hispanic Black; Mexican American; other Hispanic; and non-Hispanic other race, including multiracial [NHANES variable RIDRETH1]); Mexican American and other Hispanic were collapsed into a single Hispanic category. Body mass index (BMI) was calculated as weight (in kilograms)/height squared (in meters square); weight and height were obtained from measurements taken in NHANES mobile examination centers.7 BMI was classified as normal or underweight (BMI < 25 kg/m2), overweight (BMI 25 – <30 kg/m2), or having obesity (BMI ≥ 30 kg/m2).12
Analytic Sample
The 2007/2008 to 2017/2018 NHANES included 36,580 adults aged 18 years or older. Sample sizes ranged from a low of 5856 in 2017/2018 to a high of 6527 in 2009/2010. Physical activity data were complete for 36,418 (99.6%) respondents. An additional 49 respondents (0.1%) were missing data on educational attainment and 1917 (5.3%) were missing BMI; results stratified by education or BMI omit these respondents.
Statistical Analysis
For each NHANES cycle, we estimated the proportion of adults who were inactive, insufficiently active, and met the aerobic guideline in multidomain activity; estimates were age standardized to the 2000 US adult population.13 These estimates were then stratified by the variables described earlier. We examined changes over time in 2 ways. First, we tested for linear and higher-order trends over time using age-adjusted logistic regression models with orthogonal polynomial contrasts; when linear and higher-order trends were present, we described them as “nonmonotonic.” Second, we calculated the overall change in prevalence over this period as prevalence2017/2018 to prevalence2007/2008, expressed as percentage point differences, and tested for difference from 0 using adjusted Wald tests. We repeated these steps 3 additional times, analyzing leisure-time activity, occupational/household activity, and transportation activity in isolation. The domain-specific classification into categories of inactivity, insufficient activity, and meeting the aerobic guideline ignores any activity reported in other domains.
All analyses were performed in Stata (version 13.1; Stata Corporation, College Station, TX). We followed all NHANES analytic guidelines,7 including those for variance estimation, using interview sampling weights when all data were from interviews and using Mobile Examination Center weights when including BMI.
Results
Multidomain Activity
When all domains were analyzed together, there was a significant negative linear trend in the prevalence of multidomain inactivity over the period between 2007/2008 and 2017/2018 (Figure 1; Table 2). The prevalence of insufficient multidomain activity exhibited a significant negative quadratic trend without an accompanying significant linear trend (Figure 1). The prevalence of meeting the aerobic physical activity guideline increased nonmonotonically with significant positive linear and quadratic trends. Throughout the study period, changes in inactivity from one cycle to the next tended to be of similar magnitude to, but in opposite direction from, corresponding changes in meeting the aerobic guideline. Despite the linear decline in inactivity, there was no difference in the prevalence of multidomain inactivity when comparing 2007/2008 with 2017/2018 among the sample of all adults; however, the prevalence of meeting the aerobic guideline was significantly higher in 2017/2018 compared with 2007/2008 (Table 2).
—Age-adjusted prevalence of 3 levels of multidomain physical activity participation among US adults, the National Health and Nutrition Examination Survey 2007–2018. *Significant linear trend. **Significant linear and higher-order trend. ***Significant quadratic trend. †Participants were classified into participation categories based on moderate-intensity equivalent minutes per week: inactive (no reported activity of at least 10 continuous minutes), insufficiently active (some activity but not enough to meet the guideline), and meeting the aerobic guideline (≥150 min/wk of moderate-intensity equivalent activity).
Citation: Journal of Physical Activity and Health 18, S1; 10.1123/jpah.2021-0173
Prevalence of Inactivity and Meeting the Aerobic Physical Activity Guideline Using All Domains Among Adults, NHANES 2007/2008 and 2017/2018
| Inactive | Meets aerobic guideline | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2007/2008 | 2017/2018 | Chg | 2007/2008 | 2017/2018 | Chg | |||||||
| Characteristic | % | 95% CI | % | 95% CI | PP | Trend** | % | 95% CI | % | 95% CI | PP | Trend** |
| Overall | 23.1 | 21.0–25.4 | 20.9 | 19.2–22.7 | −2.2 | L | 64.1 | 61.6–66.5 | 68.1 | 66.5–69.6 | 4.0* | L, Q |
| Sex | ||||||||||||
| Male | 18.2 | 15.9–20.8 | 15.9 | 14.2–17.7 | −2.3 | 72.0 | 69.2–74.6 | 75.0 | 72.5–77.2 | 3.0 | Q | |
| Female | 27.6 | 24.9–30.5 | 25.6 | 23.3–28.0 | −2.1 | 56.9 | 53.9–59.8 | 61.8 | 59.8–63.8 | 5.0* | L | |
| Age, y | ||||||||||||
| 18–24 | 14.2 | 11.6–17.2 | 11.7 | 9.2–14.9 | −2.4 | 74.7 | 70.1–78.8 | 82.3 | 78.0–85.9 | 7.6* | L | |
| 25–34 | 15.0 | 12.4–18.1 | 14.4 | 12.3–16.9 | −0.6 | 75.6 | 72.1–78.7 | 78.5 | 75.2–81.4 | 2.9 | L | |
| 35–44 | 17.5 | 15.1–20.3 | 20.1 | 16.2–24.7 | 2.6 | 67.4 | 64.4–70.4 | 67.3 | 62.9–71.4 | −0.1 | ||
| 45–64 | 25.6 | 21.1–30.7 | 22.7 | 19.8–25.9 | −2.9 | 61.5 | 56.3–66.5 | 65.1 | 61.9–68.1 | 3.5 | ||
| 65+ | 41.6 | 36.5–46.9 | 32.8 | 28.7–37.1 | −8.8* | L | 44.0 | 38.8–49.3 | 52.6 | 47.9–57.2 | 8.6* | L |
| Race/ethnicity | ||||||||||||
| Non-Hispanic White | 19.5 | 16.5–22.9 | 19.0 | 16.7–21.4 | −0.6 | 67.6 | 64.1–71 | 71.1 | 69.1–73.0 | 3.5 | Q | |
| Non-Hispanic Black | 34.5 | 31.2–38.0 | 27.3 | 23.8–31.0 | −7.2* | L, Q | 51.3 | 46.8–55.8 | 61.6 | 57.8–65.2 | 10.3* | L |
| Hispanic | 32.3 | 27.6–37.4 | 24.7 | 22.3–27.4 | −7.6* | L | 56.3 | 51.0–61.5 | 65.2 | 61.5–68.6 | 8.9* | L |
| Non-Hispanic other | 26.3 | 20.6–32.9 | 22.2 | 19.2–25.6 | −4.1 | 61.3 | 55.8–66.6 | 61.2 | 56.6–65.6 | 0.1 | ||
| Education | ||||||||||||
| <High school graduate | 30.9 | 27.9–34.1 | 31.0 | 27.8–34.4 | 0.1 | 58.0 | 54.5–61.4 | 57.5 | 53.8–61.1 | −0.5 | ||
| High school Graduate | 25.7 | 23.9–27.7 | 21.7 | 19.3–24.3 | −4.0* | L | 62.4 | 60.4–64.4 | 68.4 | 65.4–71.3 | 6.0* | L, Q |
| Some college | 20.5 | 17.8–23.6 | 19.8 | 17.1–22.9 | −0.7 | 66.4 | 62.7–69.9 | 67.5 | 64.5–70.3 | 1.1 | Q | |
| ≥College graduate | 16.1 | 13.4–19.4 | 16.6 | 13.4–20.3 | 0.4 | 69.6 | 65.5–73.4 | 73.1 | 68.6–77.1 | 3.5 | ||
| BMI category | ||||||||||||
| Normal/underweight | 20.4 | 17.2–23.9 | 17.9 | 15.4–20.7 | −2.5 | 67.1 | 62.5–71.4 | 73.0 | 70.2–75.7 | 5.9* | L | |
| Overweight | 19.0 | 16.9–21.2 | 19.7 | 17.0–22.7 | 0.7 | 68.6 | 66.9–70.2 | 69.5 | 66.5–72.3 | 0.9 | ||
| Obesity | 28.0 | 25.3–30.8 | 22.4 | 19.9–25.1 | −5.6* | L, Q | 58.2 | 55.1–61.1 | 65.0 | 61.8–68.2 | 6.9* | L, Q |
Abbreviations: BMI, body mass index; C, cubic; CI, confidence interval; Chg, change; L, linear; NHANES, National Health and Nutrition Examination Survey; PP, percentage points; Q, quadratic.
*Significantly different from 0 (adjusted Wald test P < .05). **Letters indicate presence of significant trends: L, Q, and C.
In stratified analyses of multidomain activity, the prevalence of inactivity was significantly lower in 2017/2018 compared with 2007/2008 among adults aged 65 years or older, non-Hispanic Blacks, Hispanics, adults with a high school education, and adults with obesity (Table 2). These groups also exhibited significant negative linear trends, though the trends were nonmonotonic among non-Hispanic Blacks and adults with obesity. The prevalence of meeting the aerobic guideline was significantly higher in 2017/2018 compared with 2007/2008 among women, adults aged 18–24 or ≥65 years, non-Hispanic Blacks, Hispanics, adults with a high school education, normal or underweight adults, and adults with obesity. All of these groups plus adults aged 25–34 years exhibited significant positive linear trends, though trends were nonmonotonic among adults with a high school education and adults with obesity. Men, non-Hispanic Whites, and adults with some college education exhibited positive quadratic trends without accompanying significant linear trends. Estimates of multidomain insufficient activity participation by subgroup are available in Supplementary Table 1 (available online).
Leisure-Time Activity
Among all adults, when leisure-time physical activity was analyzed in isolation, neither inactivity nor insufficient activity exhibited significant trends over this period, whereas meeting the aerobic guideline in leisure time exhibited a statistically significant positive linear trend (Figure 2). There was no difference in the prevalence of leisure-time inactivity or meeting the physical activity guidelines when comparing 2007/2008 with 2017/2018 (Table 3).
—Age-adjusted prevalence of 3 levels of domain-specific physical activity participation among US adults, the National Health and Nutrition Examination Survey 2007–2018. *Significant linear trend. **Significant linear and higher-order trend. ***Participants were classified into participation categories based on moderate-intensity equivalent minutes per week: inactive (no reported activity of at least 10 continuous minutes), insufficiently active (some activity but not enough to meet the guideline), and meeting the aerobic guideline (≥150 min/wk of moderate-intensity equivalent activity).
Citation: Journal of Physical Activity and Health 18, S1; 10.1123/jpah.2021-0173
Prevalence of Inactivity and Meeting the Aerobic Physical Activity Guideline in Leisure-Time Activity Among Adults, NHANES 2007/2008 and 2017/2018
| Inactive | Meets aerobic guideline | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2007/2008 | 2017/2018 | Chg | 2007/2008 | 2017/2018 | Chg | |||||||
| Characteristics | % | 95% CI | % | 95% CI | PP | Trend** | % | 95% CI | % | 95% CI | PP | Trend** |
| Overall | 48.2 | 43.4–53.1 | 45.8 | 42.4–49.3 | −2.4 | 35.3 | 31.4–39.5 | 38.6 | 35.9–41.3 | 3.3 | L | |
| Sex | ||||||||||||
| Male | 44.6 | 39.0–50.4 | 42.4 | 38.6–46.3 | −2.2 | 39.4 | 35.3–43.7 | 43.5 | 40.0–47.0 | 4.1 | ||
| Female | 51.5 | 47.1–55.9 | 48.8 | 44.9–52.8 | −2.7 | 31.5 | 27.4–35.9 | 34.1 | 31.1–37.3 | 2.6 | L | |
| Age, y | ||||||||||||
| 18–24 | 33.7 | 30.0–37.5 | 35.6 | 30.3–41.4 | 2.0 | 48.7 | 43.3–54.0 | 55.2 | 48.3–61.9 | 6.6 | ||
| 25–34 | 38.6 | 32.6–45.0 | 37.7 | 32.8–42.8 | −0.9 | 44.9 | 38.3–51.7 | 48.7 | 44.6–52.8 | 3.8 | L | |
| 35–44 | 43.7 | 38.4–49.1 | 46.7 | 40.2–53.4 | 3.1 | 37.8 | 34.3–41.4 | 35.5 | 30.6–40.7 | −2.3 | ||
| 45–64 | 54.5 | 46.5–62.3 | 48.8 | 43.4–54.2 | −5.7 | 29.9 | 23.6–37.1 | 33.2 | 28.0–39.0 | 3.3 | ||
| 65+ | 64.4 | 57.9–70.4 | 55.8 | 51.1–60.4 | −8.6* | L | 21.3 | 17.1–26.2 | 28.6 | 24.9–32.6 | 7.3* | L |
| Race/ethnicity | ||||||||||||
| Non-Hispanic White | 43.8 | 36.3–51.5 | 42.8 | 38.2–47.5 | −0.9 | 38.4 | 32.3–44.9 | 40.1 | 36.8–43.6 | 1.7 | ||
| Non-Hispanic Black | 57.1 | 54.5–59.6 | 52.0 | 47.5–56.6 | −5.0 | L, C | 28.6 | 25.5–31.9 | 35.5 | 32.4–38.8 | 7.0* | L |
| Hispanic | 63.1 | 60.0–66.1 | 53.7 | 50.2–57.2 | −9.4* | L, Q | 26.5 | 24.8–28.2 | 33.5 | 29.6–37.7 | 7.1* | L |
| Non-Hispanic other | 48.5 | 40.8–56.2 | 45.7 | 40.0–51.5 | −2.8 | 31.9 | 25.8–38.7 | 38.5 | 32.9–44.4 | 6.6 | ||
| Education | ||||||||||||
| <High school graduate | 69.0 | 66.2–71.6 | 68.9 | 64.3–73.1 | −0.1 | Q | 20.3 | 17.6–23.3 | 21.2 | 18.4–24.3 | 0.9 | |
| High school graduate | 55.2 | 50.2–60.1 | 57.6 | 54.1–61.1 | 2.5 | 30.9 | 27.2–34.9 | 27.9 | 26.0–30.0 | −3.0 | ||
| Some college | 43.8 | 38.5–49.4 | 45.2 | 41.8–48.7 | 1.4 | 36.1 | 31.8–40.7 | 39.1 | 35.5–42.8 | 3.0 | ||
| ≥College graduate | 29.8 | 25.9–34.0 | 26.0 | 22.4–30.0 | −3.8 | 52.0 | 47.4–56.6 | 54.9 | 49.8–59.9 | 2.9 | ||
| BMI category | ||||||||||||
| Normal/underweight | 44.8 | 38.6–51.1 | 39.9 | 34.8–45.3 | −4.9 | 39.8 | 33.6–46.4 | 43.9 | 38.9–48.9 | 4.1 | ||
| Overweight | 42.8 | 37.6–48.1 | 40.3 | 37.2–43.4 | −2.5 | 39.0 | 34.0–44.3 | 44.6 | 40.2–49.2 | 5.6 | ||
| Obesity | 55.0 | 51.8–58.0 | 51.9 | 47.8–56.1 | −3.0 | 28.8 | 26.6–31.2 | 31.2 | 27.4–35.2 | 2.3 | ||
Abbreviations: BMI, body mass index; C, cubic; CI, confidence interval; Chg, change; L, linear; NHANES, National Health and Nutrition Examination Survey; PP, percentage points; Q, quadratic.
*Significantly different from 0 (adjusted Wald test P < .05). **Letters indicate presence of significant trends: L, Q, and C.
Most groups in stratified analyses demonstrated no difference in the prevalence of leisure-time inactivity when comparing 2007/2008 with 2017/2018. Exceptions included significantly lower inactivity in 2017/2018 versus 2007/2008 among adults aged ≥65 years and Hispanics (Table 3). These 2 groups and non-Hispanic Blacks also exhibited significant negative linear trends in leisure-time inactivity; trends were nonmonotonic among non-Hispanic Blacks and Hispanics. Adults with less than a high school education exhibited a significant higher order trend in leisure-time inactivity with no accompanying significant linear trend. Similarly, most groups in the stratified analysis demonstrated no difference in the prevalence of meeting the aerobic guideline in leisure time from 2007/2008 to 2017/2018. Exceptions included significantly higher prevalence in 2017/2018 compared with 2007/2008 among adults aged ≥65 years, non-Hispanic Blacks, and Hispanics. These groups, plus adults aged 25–34 years, also exhibited significant positive linear trends in meeting the guideline over this period. Estimates of leisure-time insufficient activity are available in Supplementary Table 2 (available online).
Occupational/Household Activity
Among all adults, when occupational/household activity was analyzed in isolation, inactivity exhibited a significant nonmonotonic negative trend, insufficient activity exhibited a small but statistically significant positive linear trend, and meeting the aerobic guideline increased nonmonotonically (Figure 2). When focused on a particular time, changes in meeting the guideline were usually of similar magnitude to, but in opposite direction from, corresponding changes in inactivity. The prevalence of occupational/household inactivity was significantly lower in 2017/2018 than in 2007/2008, whereas the prevalence of meeting the aerobic guideline in occupational/household activity was significantly higher in 2017/2018 than in 2007/2008 (Table 4)
Prevalence of Inactivity and Meeting the Aerobic Physical Activity Guideline in Occupational/Household Activity Among Adults, NHANES 2007/2008 and 2017/2018
| Inactive | Meets aerobic guideline | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2007/2008 | 2017/2018 | Chg | 2007/2008 | 2017/2018 | Chg | |||||||
| Characteristics | % | 95% CI | % | 95% CI | PP | Trend** | % | 95% CI | % | 95% CI | PP | Trend** |
| Overall | 53.3 | 50.6–56.0 | 47.7 | 45.3–50.2 | −5.6* | L, Q | 39.7 | 37.2–42.4 | 44.2 | 41.3–47.2 | 4.5* | L, Q |
| Sex | ||||||||||||
| Male | 45.5 | 41.3–49.7 | 41.7 | 38.6–44.7 | −3.8 | L, Q | 48.4 | 44.6–52.3 | 50.2 | 46.4–54.1 | 1.8 | Q |
| Female | 60.7 | 58.7–62.6 | 53.3 | 50.5–56.1 | −7.4* | L, Q | 31.6 | 29.7–33.6 | 38.6 | 35.7–41.7 | 7.0* | L, Q |
| Age, y | ||||||||||||
| 18–24 | 46.2 | 40.9–51.6 | 40.1 | 34.9–45.5 | −6.1 | L, Q | 47.0 | 41.9–52.2 | 53.0 | 47.0–58.9 | 6.0 | L, Q |
| 25–34 | 46.5 | 42.0–51.0 | 39.7 | 35.5–44.1 | −6.8* | L, Q | 47.7 | 42.7–52.8 | 53.6 | 49.5–57.7 | 5.9 | L, Q |
| 35–44 | 53.4 | 48.3–58.5 | 50.2 | 46.1–54.3 | −3.3 | Q | 40.1 | 34.8–45.6 | 41.4 | 36.3–46.6 | 1.3 | Q |
| 45–64 | 52.7 | 49.3–56.0 | 48.1 | 45.7–50.6 | −4.6* | L, Q | 39.4 | 35.9–43.1 | 44.0 | 40.3–47.9 | 4.6 | L, Q |
| 65+ | 67.0 | 62.4–71.3 | 58.2 | 51.6–64.5 | −8.8* | L, Q | 25.8 | 22.2–29.8 | 31.5 | 26.0–37.7 | 5.7 | L, Q |
| Race/ethnicity | ||||||||||||
| Non-Hispanic White | 49.0 | 46.3–51.7 | 43.9 | 40.8–47.0 | −5.1* | L, Q | 43.0 | 40.1–46.0 | 47.6 | 44.0–51.2 | 4.6 | L, Q |
| Non-Hispanic Black | 66.2 | 62.7–69.5 | 54.9 | 51.6–58.1 | −11.3* | L, Q | 29.3 | 25.9–32.9 | 38.8 | 35.0–42.6 | 9.5* | L, Q |
| Hispanic | 60.5 | 56.0–64.8 | 51.7 | 48.1–55.4 | −8.8* | L, Q | 35.2 | 31.1–39.6 | 42.2 | 38.2–46.4 | 7.0* | L, Q |
| Non-Hispanic other | 64.8 | 57.1–71.8 | 59.7 | 54.0–65.2 | −5.1 | Q | 31.3 | 24.3–39.3 | 30.7 | 25.1–36.8 | −0.7 | Q |
| Education | ||||||||||||
| <High school graduate | 54.4 | 50.9–57.9 | 52.5 | 49.3–55.7 | −1.9 | L, Q | 39.9 | 36.3–43.7 | 43.7 | 40.2–47.2 | 3.7 | L, Q |
| High school graduate | 48.4 | 45.2–51.6 | 39.5 | 36.4–42.7 | −8.9* | L, Q | 45.0 | 42.5–47.5 | 54.4 | 50.8–57.9 | 9.4* | L, Q |
| Some college | 48.8 | 44.5–53.2 | 43.4 | 40.7–46.2 | −5.4* | L, Q | 44.7 | 40.4–49.0 | 47.1 | 44.7–49.6 | 2.4 | L, Q |
| ≥College graduate | 60.3 | 55.7–64.6 | 56.7 | 52.1–61.1 | −3.6 | L, Q | 31.1 | 26.5–36.0 | 33.0 | 29.3–37.0 | 1.9 | Q |
| BMI category | ||||||||||||
| Normal/underweight | 53.0 | 49.3–56.7 | 48.0 | 42.9–53.2 | −5.0 | L, Q | 38.7 | 35.6–42.0 | 44.4 | 39.2–49.7 | 5.7 | L, Q |
| Overweight | 50.5 | 47.2–53.7 | 50.5 | 47.7–53.4 | 0.1 | Q, C | 42.9 | 40.2–45.6 | 42.1 | 38.7–45.5 | −0.8 | Q, C |
| Obesity | 55.6 | 51.6–59.4 | 43.7 | 40.0–47.5 | −11.8* | L, Q | 37.9 | 34.4–41.6 | 47.1 | 43.8–50.5 | 9.2* | L, Q |
Abbreviations: BMI, body mass index; C, cubic; CI, confidence interval; Chg, change; L, linear; NHANES, National Health and Nutrition Examination Survey; PP, percentage points; Q, quadratic.
*Significantly different from 0 (adjusted Wald test P < .05). **Letters indicate presence of significant trends: L, Q, and C.
In stratified analyses, the prevalence of occupational/household inactivity was significantly lower in 2017/2018 than in 2007/2008 among most subgroups (Table 4). In addition, most subgroups exhibited significant nonmonotonic negative linear trends, whereas only 3 (adults aged 35–44 y, non-Hispanic other, and adults who were overweight) exhibited higher-order trends with no accompanying significant linear trend. The prevalence of meeting the aerobic guideline in occupational/household activity was significantly higher in 2017/2018 than in 2007/2008 among women, non-Hispanic Blacks, Hispanics, adults with a high school education, and adults with obesity. Most subgroups exhibited significant nonmonotonic positive linear trends, whereas 5 groups (men, adults aged 35–44 y, non-Hispanic other, adults with at least a college degree, and adults with obesity) exhibited higher-order trends only. Estimates of occupational/household insufficient activity by subgroup are available in Supplementary Table 3 (available online).
Transportation Activity
Among all adults, when transportation activity was analyzed in isolation, inactivity increased nonmonotonically, insufficient activity exhibited no significant trend, and meeting the aerobic guideline exhibited a negative nonmonotonic trend (Figure 2). There was no difference in the prevalence of transportation-related inactivity or in meeting the aerobic guideline in transportation activity when comparing 2007/2008 with 2017/2018 (Table 5).
Prevalence of Inactivity and Meeting the Aerobic Physical Activity Guideline in Transportation Activity Among Adults, NHANES 2007/2008 and 2017/2018
| Inactive | Meets aerobic guideline | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2007/2008 | 2017/2018 | Chg | 2007/2008 | 2017/2018 | Chg | |||||||
| Characteristics | % | 95% CI | % | 95% CI | PP | Trend** | % | 95% CI | % | 95% CI | PP | Trend** |
| Overall | 76.1 | 72.7–79.2 | 78.1 | 76.0–80.0 | 2.0 | L, Q, C | 13.6 | 11.3–16.3 | 10.9 | 9.6–12.4 | −2.7 | L, Q, C |
| Sex | ||||||||||||
| Male | 74.4 | 70.1–78.4 | 74.9 | 72.1–77.6 | 0.5 | Q, C | 15.6 | 13.1–18.4 | 12.6 | 10.3–15.3 | −3.0 | L, Q |
| Female | 77.7 | 74.6–80.4 | 81.1 | 79.3–82.8 | 3.4* | L, Q | 11.8 | 9.4–14.7 | 9.4 | 8.1–10.8 | −2.5 | L, Q, C |
| Age, y | ||||||||||||
| 18–24 | 62.5 | 55.7–68.8 | 68.5 | 60.9–75.3 | 6.0 | L | 21.9 | 16.8–27.9 | 16.3 | 10.2–25.0 | −5.6 | |
| 25–34 | 72.7 | 67.9–77.1 | 73.5 | 68.4–78.0 | 0.8 | 17.2 | 13.4–21.8 | 13.4 | 10.6–16.9 | −3.7 | ||
| 35–44 | 76.3 | 71.3–80.7 | 76.3 | 71.4–80.5 | −0.1 | C | 12.8 | 10.6–15.5 | 10.7 | 8.3–13.7 | −2.2 | L, C |
| 45–64 | 79.4 | 74.9–83.3 | 82.7 | 80.4–84.8 | 3.2 | L, Q | 11.4 | 9–14.4 | 9.3 | 7.8–11.1 | −2.1 | L, Q, C |
| 65+ | 84.0 | 80.6–86.9 | 84.6 | 81.2–87.6 | 0.7 | 8.5 | 6.8–10.5 | 7.4 | 5.3–10.4 | −1.1 | ||
| Race/ethnicity | ||||||||||||
| Non-Hispanic White | 77.6 | 75.0–80.0 | 80.9 | 78.3–83.3 | 3.3 | L, Q | 12.5 | 10.2–15.1 | 9.4 | 7.6–11.5 | −3.1 | L, Q |
| Non-Hispanic Black | 77.7 | 73.3–81.5 | 74.6 | 71.1–77.9 | −3.1 | Q, C | 11.4 | 8.9–14.4 | 13.2 | 10.8–15.9 | 1.8 | Q, C |
| Hispanic | 70.6 | 64.8–75.8 | 73.6 | 69.8–77.1 | 3.0 | L, C | 18.9 | 14.8–23.8 | 14.4 | 11.5–17.8 | −4.5 | L |
| Non-Hispanic other | 69.6 | 54.7–81.3 | 70.4 | 64.6–75.7 | 0.9 | 17.6 | 10–29.1 | 13.3 | 11.0–15.9 | −4.3 | ||
| Education | ||||||||||||
| <High school graduate | 70.4 | 65.1–75.2 | 73.2 | 68.2–77.6 | 2.7 | L, C | 19.8 | 15.5–25 | 14.3 | 11.2–18.0 | −5.6 | L |
| High school graduate | 78.7 | 74.3–82.4 | 78.0 | 75.3–80.5 | −0.6 | 11.3 | 8.8–14.3 | 12.0 | 10.2–14.0 | 0.7 | ||
| Some college | 76.1 | 72.3–79.5 | 80.5 | 77.3–83.3 | 4.4 | L, Q, C | 13.6 | 11–16.6 | 9.5 | 7.6–11.7 | −4.1 | L, Q, C |
| ≥College graduate | 77.6 | 72.4–82.0 | 78.6 | 74.7–82.1 | 1.1 | Q | 11.6 | 9.2–14.5 | 9.8 | 7.7–12.5 | −1.8 | Q |
| BMI category | ||||||||||||
| Normal/underweight | 72.2 | 67.3–76.7 | 73.4 | 69.9–76.7 | 1.2 | 16.7 | 13.3–20.8 | 13.8 | 11.5–16.6 | −2.9 | ||
| Overweight | 76.8 | 74.0–79.3 | 77.4 | 73.1–81.2 | 0.6 | Q | 12.4 | 10.2–15.1 | 10.9 | 8.5–13.9 | −1.5 | L, Q |
| Obesity | 79.1 | 76.0–82.0 | 82.4 | 79.8–84.7 | 3.3 | L, Q, C | 11.8 | 9.3–14.7 | 9.1 | 7.6–10.7 | −2.7 | L, C |
Abbreviations: BMI, body mass index; C, cubic; CI, confidence interval; Chg, change; L, linear; NHANES, National Health and Nutrition Examination Survey; PP, percentage points; Q, quadratic.
*Significantly different from 0 (adjusted Wald test P < .05). **Letters indicate presence of significant trends: L, Q, and C.
In stratified analyses, the prevalence of transportation-related inactivity was significantly higher in 2017/2018 compared with 2007/2008 among women (Table 5). There were significant nonmonotonic positive linear trends in inactivity among women, adults aged 45–64 years, non-Hispanic Whites, Hispanics, adults with less than a high school education or some college, and adults with obesity. Adults aged 18–24 years exhibited a significant positive linear trend, whereas men, adults aged 35–44 years, non-Hispanic Blacks, college graduates, and adults who were overweight exhibited only higher-order trends with no accompanying significant linear trend. The prevalence of meeting the aerobic guideline in transportation activity was not significantly different in 2017/2018 than in 2007/2008 among any subgroups. Ten of 18 subgroups examined in this analysis exhibited significant negative linear trends in meeting the guideline (8 of which were nonmonotonic). Hispanics and adults with a college education exhibited higher-order trends with no accompanying linear trend. Estimates of transportation-related insufficient activity by subgroup are available in Supplementary Table 4 (available online).
Discussion
Among US adults from 2007/2008 to 2017/2018, the prevalence of meeting the aerobic guideline through multidomain activity increased while inactivity decreased overall and for several subgroups, including several subgroups with previously documented low activity participation (eg, adults aged ≥65 y, non-Hispanic Blacks). Changes in domain-specific physical activity participation varied: leisure activity changed relatively little, whereas the combined occupational/household domain exhibited the most consistent increases in meeting the guideline and decreases in inactivity across subgroups. Furthermore, participation in transportation activity began and remained relatively low. Efforts to continue increases in participation among subgroups that have historically reported lower physical activity levels than their peers may help narrow disparities in physical activity participation. Interventions designed to increase transportation activity, including providing activity-friendly routes to everyday destinations, may address low participation in this domain.
When all domains were considered, the magnitude of increase in meeting the aerobic guideline varied across subgroups, helping to reduce previously documented disparities in physical activity participation.4,10,14 For example, in 2007/2008, there was a 31.6% difference in meeting the aerobic guideline when comparing adults aged 65 years or older (44.0%) with those aged 25–34 years (75.6%), and this difference narrowed to 25.9% in 2017/2018 (52.6% and 78.5%, respectively). Similar findings were observed when comparing non-Hispanic Blacks or Hispanics with non-Hispanic Whites and when comparing adults with a high school education with adults with a college education. Physical activity confers many health benefits2 and is associated with reduced healthcare costs15; continued narrowing of differences in participation in these groups could help address health disparities and the economic burden thereof. Physical activity promotion efforts that are tailored to these groups could continue this progress in equitable physical activity participation.16,17
This article complements previously reported findings on multidomain physical activity from NHANES. In 2019, Du et al8 examined changes in multidomain physical activity among adults aged 20 years and older in NHANES 2007/2008 to 2015/2016 after adjusting for several covariates. They reported no significant trends in prevalence of meeting the aerobic guideline overall, but significant linear increases were observed among selected subgroups, including women and non-Hispanic Blacks. Our study examined age-standardized prevalence estimates, and after adding data from 2017/2018, there was a significant trend for meeting the aerobic guideline overall and for several additional subgroups. Furthermore, our analysis suggests that the increase in meeting the guideline is accompanied by decreases in inactivity. This apparent trend for greater prevalence of meeting the guideline and lower prevalence of inactivity is encouraging as it aligns with the guidelines recommendation to avoid inactivity. Also, shifting physical activity participation from lower to higher categories is the goal of the Centers for Disease Control and Prevention’s Active People, Healthy NationSM initiative to increase the activity levels of 27 million Americans by 2027.18 If sustained, the changes documented here may help reach this goal.
These and other recent results6,8 suggest that over two-thirds of adults meet the aerobic guideline when all domains of activity are assessed. As would be expected, this is higher than leisure-only assessments from the National Health Interview Survey (NHIS) in which 50.2% of adults met the guideline in 2018.19 These results are encouraging as it appears that many adults are benefiting from the health benefits of meeting the aerobic guideline, but they should be interpreted with some caution. Previous reports suggest that multidomain physical activity questionnaires may lead to overreporting among respondents.20 Continued advancement of physical activity assessment techniques, including mobile applications,21 device-based measurement of bodily movements,21 and crowd-sourced or “big-data” approaches22 may allow refinement of these estimates in future surveillance efforts.
Domain-specific findings can identify the contexts in which physical activity is changing and provide insights for future activity promotion strategies. For example, we documented increases in meeting the guideline in multidomain activity among non-Hispanic blacks and Hispanics. Domain-specific analyses suggest that these changes can be attributed to increases in meeting the guideline during leisure and occupational/household activities, whereas transportation activity changed inconsistently (non-Hispanic Blacks) or decreased (Hispanics). The generally low prevalence of meeting the guideline during transportation activity among these and other subgroups suggests that active transportation may be an underutilized source of aerobic activity.23 Providing activity-friendly routes to everyday destinations is a proven strategy to increase physical activity in general and may particularly favor walking and bicycling to get from place to place (ie, for transportation).9 Tailoring such interventions to the needs of individuals most likely to report low activity participation could help to continue the narrowing of physical activity disparities documented in this report.
In estimates limited to leisure-time physical activity, we found a linear increase in the prevalence of meeting the aerobic guideline among adults overall. This finding agrees with recent reports from NHIS showing overall increases in meeting the aerobic guideline in leisure time,3,19 but the prevalence was consistently lower in NHANES than NHIS (eg, 38.6% in 2017/2018 in NHANES and 54.2% in 2018 in NHIS19). The reasons for these discrepant prevalence estimates are not entirely clear, but differences in assessment may play a role. In NHANES, leisure activity is assessed after occupational/household and transportation activities are reported, and respondents are asked to exclude activities reported in preceding sections; some activities that are not clearly leisure (eg, gardening or walking the dog) could be reported under other domains. Conversely, all such activities might be captured under leisure activity in NHIS, which is the only domain assessed. Moreover, NHIS asks respondents to report participation in light-intensity activity combined with moderate-intensity activity. Thus, although both NHANES and NHIS assess “leisure-time physical activity,” the estimates derived from each represent slightly different constructs, and comparisons should be made with caution. Advances in physical activity assessments that better differentiate among domains and activity intensity (eg, the ACT24 smartphone-based activity diary21,24) may better disentangle the relationships among leisure, household, occupational, and transportation activities.
In the combined occupational/household domain, the patterns of change were markedly similar across subgroups and the overall sample: meeting the guideline in this domain decreased to a low point in 2011/2012 then increased thereafter, resulting in significant, though inconsistent, trends for increasing prevalence of meeting the guideline in this domain. Trends in inactivity formed a near mirror image of those for meeting the guideline. Deciphering the underlying cause of these results is difficult given the combination of occupational and household activities in a single assessment; changes in either or both could account for the observed results. Previous reports have documented a decades-long reduction in the physical demands of the US workforce beginning in the 1960s.25 Assuming this long-term trend has continued, these findings could suggest increased household activity since 2011/2012. Again, additional surveillance with assessment techniques that better disentangle activity domains could clarify these changes.
This report is subject to at least 3 limitations. First, NHANES physical activity data are self-reported and subject to social desirability and other recall biases20; it is unknown whether these biases differ across domains. Second, we performed a complete case analysis, which could bias results if those with complete information are different from those without; however, physical activity data were complete for over 99% of the analytic sample. Finally, multidomain activity questionnaires may encourage overreporting due to activity being counted in multiple domains,20 which would lead to overestimation of activity prevalence. Strengths of this article include a large, nationally representative sample.
Conclusions
When assessing multidomain activity among US adults from 2007/2008 to 2017/2018, the prevalence of inactivity decreased and meeting the aerobic physical activity guideline increased overall and for several subgroups. Results from domain-specific analyses were mixed; however, inactivity decreased and meeting the aerobic guideline increased most consistently in the occupational/household domain. Several subgroups with previously documented low activity participation (eg, adults aged ≥65 y, non-Hispanic Blacks) reported increased prevalence of meeting the aerobic guideline relative to their more active counterparts. Continued tailoring of physical activity programs to these groups may help continue this progress and ameliorate chronic disease disparities. Transportation-related activity may be an underutilized source of physical activity in this country.
Acknowledgments
The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the official position of the CDC or the NIH.
References
- 1.↑
United States Department of Health and Human Services. Physical Activity Guidelines for Americans. 2nd ed. Washington, DC: U.S. Dept. of Health and Human Services; 2018.
- 2.↑
Physical Activity Guidelines Advisory Committee. 2018 Physical Activity Guidelines Advisory Committee Scientific Report. Washington, DC: U.S. Department of Health and Human Services; 2018.
- 3.↑
Centers for Disease Control and Prevention. Trends in meeting the 2008 Physical Activity Guidelines, 2008–2017. 2018. https://www.cdc.gov/physicalactivity/downloads/trends-in-the-prevalence-of-physical-activity-508.pdf. Accessed 6 February 2019.
- 4.↑
United States Department of Health and Human Services. 2020 Topics and objectives, physical activity. 2020. https://www.healthypeople.gov/2020/topics-objectives/topic/physical-activity/objectives. Accessed 6 February 2020.
- 5.↑
Whitfield GP, Carlson SA, Ussery EN, Fulton JE, Galuska DA, Petersen R. Trends in meeting physical activity guidelines among urban and rural dwelling adults—United States, 2008–2017. MMWR Morb Mortal Wkly Rep. 2019;68(23):513–518. PubMed ID: 31194722 doi:10.15585/mmwr.mm6823a1
- 6.↑
Whitfield GP, Ussery EN, Carlson SA. Combining data from assessments of leisure, occupational, household, and transportation physical activity among US adults, NHANES 2011–2016. Prev Chronic Dis. 2020;17:E117. PubMed ID: 33006543
- 7.↑
National Center for Health Statistics. National health and nutrition examination survey. 2020; https://www.cdc.gov/nchs/nhanes/index.htm. Accessed 14 August 2020.
- 8.↑
Du Y, Liu B, Sun Y, Snetselaar LG, Wallace RB, Bao W. Trends in adherence to the physical activity guidelines for americans for aerobic activity and time spent on sedentary behavior among US adults, 2007 to 2016. JAMA Network Open. 2019;2(7):e197597. PubMed ID: 31348504 doi:10.1001/jamanetworkopen.2019.7597
- 9.↑
Community Preventive Services Task Force. Physical activity. 2018. https://www.thecommunityguide.org/topic/physical-activity. Accessed February 5, 2019.
- 10.↑
Scholes S, Bann D. Education-related disparities in reported physical activity during leisure-time, active transportation, and work among US adults: repeated cross-sectional analysis from the National Health and Nutrition Examination Surveys, 2007 to 2016. BMC Public Health. 2018;18(1):926. PubMed ID: 30055611 doi:10.1186/s12889-018-5857-z
- 11.↑
Centers for Disease Control and Prevention. National health and nutrition examination survey 2011-2012 data documentation, codebook, and frequencies physical activity (PAQ_G). 2013; https://wwwn.cdc.gov/Nchs/Nhanes/2011-2012/PAQ_G.htm. Accessed 6 February 2020.
- 12.↑
Centers for Disease Control and Prevention. Defining adult overweight and obesity. 2020. https://www.cdc.gov/obesity/adult/defining.html. Accessed 26 January 2021.
- 13.↑
Klein RJ, Schoenborn CA. Age adjustment using the 2000 projected U.S. population. Healthy People 2010 Stat Notes. 2001(20):1–10.
- 14.↑
National Center for Health Statistics. Health, United States, 2018. Hyatsville, MD: Centers for Disease Control and Prevention; 2019.
- 15.↑
Carlson SA, Fulton JE, Pratt M, Yang Z, Adams EK. Inadequate physical activity and health care expenditures in the United States. Prog Cardiovasc Dis. 2015;57(4):315–323. PubMed ID: 25559060 doi:10.1016/j.pcad.2014.08.002
- 16.↑
Community Preventive Services Task Force. Physical activity: digital health interventions for adults 55 years and older. 2019. https://www.thecommunityguide.org/sites/default/files/assets/PA-Digital-Health-55-Years-Older.pdf. Accessed 27 January 2021.
- 17.↑
Zubala A, MacGillivray S, Frost H, et al. Promotion of physical activity interventions for community dwelling older adults: A systematic review of reviews. PLoS One. 2017;12(7):e0180902. PubMed ID: 28700754 doi:10.1371/journal.pone.0180902
- 18.↑
Fulton JE, Buchner DM, Carlson SA, et al. CDC’s active people, healthy nation(SM): creating an active America, together. J Phys Act Health. 2018;15(7):469–473. PubMed ID: 29932005 doi:10.1123/jpah.2018-0249
- 19.↑
Whitfield GP, Hyde ET, Carlson SA. Participation in leisure-time aerobic physical activity among adults, National Health Interview Survey, 1998–2018. J Phys Act Health. 2021.
- 20.↑
Rzewnicki R, Vanden Auweele Y, De Bourdeaudhuij I. Addressing overreporting on the International Physical Activity Questionnaire (IPAQ) telephone survey with a population sample. Public Health Nutr. 2003;6(3):299–305. PubMed ID: 12740079 doi:10.1079/PHN2002427
- 21.↑
Matthews CE, Kozey Keadle S, Moore SC, et al. Measurement of active and sedentary behavior in context of large epidemiologic studies. Med Sci Sports Exerc. 2018;50(2):266–276. PubMed ID: 28930863 doi:10.1249/MSS.0000000000001428
- 22.↑
Lee K, Sener IN. Emerging data for pedestrian and bicycle monitoring: Sources and applications. Transport Res Interdisc Persp. 2020;4:100095.
- 23.↑
Whitfield GP, Paul P, Wendel AM. Active transportation surveillance—United States, 1999–2012. MMWR Surveill Summ. 2015;64(7):1–17. PubMed ID: 26313567 doi:10.15585/mmwr.ss6407a1
- 24.↑
Saint Maurice P. et al. Amount, type, and timing of moderate-to-vigorous physical activity among US adults. J Phys Act Health. 2021.
- 25.↑
Church TS, Thomas DM, Tudor-Locke C, et al. Trends over 5 Decades in U.S. occupation-related physical activity and their associations with obesity. PLoS One. 2011;6(5):e19657. PubMed ID: 21647427 doi:10.1371/journal.pone.0019657
