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BMI and Physical Activity, Military-Aged U.S. Population 2015–2020

  • Bryant J. Webber
    Correspondence
    Address correspondence to: Bryant J. Webber, MD, MPH, Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, 4770 Buford Highway, Atlanta GA 30341.
    Affiliations
    Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia

    Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia

    Air Force Institute of Technology, Wright-Patterson Air Force Base, Dayton, Ohio
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  • Daniel B. Bornstein
    Affiliations
    DBornsteinSolutions, LLC, Norwich, Vermont
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  • Patricia A. Deuster
    Affiliations
    Consortium for Health and Military Performance, Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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  • Francis G. O'Connor
    Affiliations
    Consortium for Health and Military Performance, Department of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
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  • Sohyun Park
    Affiliations
    Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
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  • Kenneth M. Rose
    Affiliations
    Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
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  • Geoffrey P. Whitfield
    Affiliations
    Division of Nutrition, Physical Activity, and Obesity, National Center for Chronic Disease Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia
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Open AccessPublished:September 22, 2022DOI:https://doi.org/10.1016/j.amepre.2022.08.008

      Introduction

      Obesity and physical inactivity are considered possible U.S. national security threats because of their impact on military recruitment. The objectives of this study were to estimate the prevalence of (1) BMI eligibility for military entrance, (2) adequate physical activity participation among the BMI-eligible population, and (3) combined BMI eligibility and adequate physical activity.

      Methods

      This cross-sectional study of nonpregnant, military-aged civilians (aged 17–42 years) used objectively measured weight and height data and self-reported aerobic physical activity data from the 2015–2020 National Health and Nutrition Examination Survey. BMI eligibility was defined as 19.0–27.5 kg/m2, per Department of Defense regulation. Adequate physical activity for entering initial military training was defined as ≥300 minutes/week of equivalent moderate-intensity aerobic physical activity from all domains, approximating U.S. Army guidance. Participants meeting both definitions were further classified as eligible and active. Analyses were conducted in 2021–2022.

      Results

      Of military-aged participants (unweighted n=5,964), 47.3% were eligible by BMI. Among BMI-eligible participants, 72.5% reported adequate physical activity. Taken together, 34.3% were both eligible and active. The prevalence of eligible and active status was higher among males, persons who were younger and non-Hispanic White, college graduates, and those with higher family income than among their counterparts.

      Conclusions

      Among the military-aged U.S. population, slightly under half were eligible to enter the military on the basis of their BMI, and only 1 in 3 met BMI eligibility and were adequately physically active. Equitable promotion of healthy weight achievement and physical activity participation may improve military preparedness.

      INTRODUCTION

      Physical fitness is one of several eligibility criteria for U.S. military enlistment, appointment, or induction.

      32 CFR 66.6: Enlistment, Appointment, and Induction Criteria. Amended July 1, 2022. https://www.ecfr.gov/current/title-32/subtitle-A/chapter-I/subchapter-D/part-66/section-66.6. Accessed July 29, 2022.

      Body composition is the primary parameter of physical fitness eligibility, and individual military Services may add traditional measures of physical fitness, such as aerobic capacity.

      32 CFR 66.6: Enlistment, Appointment, and Induction Criteria. Amended July 1, 2022. https://www.ecfr.gov/current/title-32/subtitle-A/chapter-I/subchapter-D/part-66/section-66.6. Accessed July 29, 2022.

      ,

      Instruction 1304.26: qualification standards for enlistment, appointment, and induction. U.S. Department of Defense. https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodi/130426p.pdf?ver=2018-10-26-085822-050. Updated October 26, 2018. Accessed July 29, 2022.

      For example, U.S. Army recruiters administer a strength and endurance examination to certify that a recruit is ready for the rigors of training and is physically prepared for the predesignated military occupation.
      U.S. Department of the Army
      FM 7-22: holistic health and fitness.
      Before graduating from initial military training (IMT), the new soldier must achieve a passing score on the Army Combat Fitness Test.
      Secretory of the Army Washington
      Army Directive 2022-05 (Army Combat Fitness Test).
      In a series of reports

      Mission: readiness. Ready, willing, and unable to serve. Strong America.November 5, 2009. https://www.strongnation.org/articles/21-ready-willing-and-unable-to-serve. Accessed July 29, 2022.

      Mission: readiness. Too fat to fight. Strong America.April 10, 2010. https://www.strongnation.org/articles/23-too-fat-to-fight. Accessed July 29, 2022.

      Mission: readiness. Still too fat to fight. Strong America. September 1, 2012. https://www.strongnation.org/articles/16-still-too-fat-to-fight. Accessed July 29, 2022.

      Mission: readiness. Unfit to fight. Strong America.April 30, 2015. https://www.strongnation.org/articles/53-unfit-to-fight. Accessed July 29, 2022.

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      drawing on published data
      • Cawley J
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      U.S. Department of Defense. Office of Under Secretary of defense for personnel and readiness, joint advertising market research and studies. Qualified military available. October 2013.

      ,

      U.S. Department of Defense. Office of Under Secretary of defense for personnel and readiness, joint advertising market research and studies. Qualified military available. October 2017.

      a consortium of retired military leaders emphasize preparedness shortcomings across the U.S. young adult population. According to the latest report, released in 2018,

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      31% of the population aged 17–24 years were ineligible to serve because of obesity. Echoing concerns raised in the 1950s,

      The federal government takes on physical fitness. John F. Kennedy Presidential Library and Museum. https://www.jfklibrary.org/learn/about-jfk/jfk-in-history/physical-fitness. Updated November 7, 2018. Accessed July 29, 2022.

      these leaders and others
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      have characterized widespread obesity and physical inactivity as threats to national security, which jeopardize retention of current service members and recruitment of new service members.
      The well-documented societal trends in health-related behaviors and obesity
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      challenge military recruitment efforts. In 2017–2018, obesity prevalence in the U.S. among persons aged 12–19 and 20–39 years was 21%
      • Fryar CD
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      and 40%,
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      respectively—up from 18%
      • Fryar CD
      • Carroll MD
      • Afful J.
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      and 31%,
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      Trends in obesity and severe obesity prevalence in U.S. youth and adults by sex and age, 2007–2008 to 2015–2016.
      respectively, in 2007–2008. Health-related behaviors of U.S. high-school students have mostly trended in the less healthful direction during this time period. Although sugar-sweetened beverage consumption has declined, it remains high,
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      Adolescent physical activity has also decreased.
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      Meanwhile, more adults aged 18–44 years are meeting the combined aerobic and muscle-strengthening physical activity guidelines in leisure time, but the 2018 prevalence remained below 25%.
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      The impact of these trends on military preparedness is unknown. The most recently published manuscript on the topic used 2007–2008 data.
      • Cawley J
      • Maclean JC.
      Unfit for service: the implications of rising obesity for U.S. military recruitment.
      Moreover, previous preparedness studies did not examine physical activity.
      • Cawley J
      • Maclean JC.
      Unfit for service: the implications of rising obesity for U.S. military recruitment.

      U.S. Department of Defense. Office of Under Secretary of defense for personnel and readiness, joint advertising market research and studies. Qualified military available. October 2017.

      Physical activity before military entrance is inversely associated with costly discharge from IMT across the Services, including in the U.S. Army,
      • Swedler DI
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      Navy,
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      It is also directly associated with physical fitness,
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      which predicts training-related musculoskeletal injury
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      The objectives of this study were to estimate the percentage of the military-aged U.S. civilian population who were eligible for military entrance by BMI, the percentage of BMI-eligible who report an adequate physical activity level for IMT, and the combined percentage who were both BMI eligible and adequately physically active. These are vital datapoints for understanding the pool of potential military recruits and for scoping obesity prevention and physical activity promotion efforts.

      METHODS

      Study Sample

      All data were acquired from the National Health and Nutrition Examination Survey (NHANES), a multistage probability survey of a nationally representative sample of the civilian, non-institutionalized U.S. population. To produce nationally reliable statistics, NHANES visits 15 counties annually and oversamples Black and Hispanic persons. Detailed methodology is available elsewhere.

      About the National Health and Nutrition Examination Survey. National Center for Health Statistics, Centers for Disease Control and Prevention. https://www.cdc.gov/nchs/nhanes/about_nhanes.htm. Updated September 15, 2017. Accessed July 29, 2022.

      This cross-sectional study incorporated the 2015–2016 cycle and the 2017–2020 (prepandemic) cycle, in which the National Center for Health Statistics (NCHS) merged data from 2017 to 2018 with data from January 2019 to March 2020, when field operations were suspended because of coronavirus disease 2019 (COVID-19).

      NHANES questionnaires, datasets, and related documentation. National Center for Health Statistics, Centers for Disease Control and Prevention. https://wwwn.cdc.gov/nchs/nhanes/Default.aspx. Updated June 15, 2022. Accessed July 29, 2022.

      NHANES is approved by the NCHS Research Ethics Review Board. All participants provided informed consent. Response rates of the examined samples in the 2015–2016 and 2017–2020 cycles were 58.7% and 46.9%, respectively.

      NHANES response rates. National Center for Health Statistics, Centers for Disease Control and Prevention. https://wwwn.cdc.gov/nchs/nhanes/responserates.aspx. Updated July 7, 2022. Accessed July 29, 2022.

      The sample was restricted to nonpregnant participants aged 17–42 years, the permissible age range for regular enlistment, appointment, or induction in the U.S. military,

      32 CFR 66.6: Enlistment, Appointment, and Induction Criteria. Amended July 1, 2022. https://www.ecfr.gov/current/title-32/subtitle-A/chapter-I/subchapter-D/part-66/section-66.6. Accessed July 29, 2022.

      and participants with missing anthropometric and physical activity data were excluded.
      In both NHANES cycles, participants reported their gender, age, race, Hispanic origin, the highest level of education, and family income in the previous calendar year. Age was categorized into 4 groups: 17–24, 25–29, 30–34, and 35–42 years. The youngest group, which represents 88% of enlisted military applicants,
      U.S. Department of Defense
      Appendix A: active component applicant tables.
      facilitates comparison with a recent report.

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      Race and Hispanic origin were merged by NCHS into a single variable and consolidated into 4 groups: non-Hispanic White, non-Hispanic Black, Hispanic, and non-Hispanic other. Education was categorized into 3 groups (less than high school, some college, and college graduate) and was restricted to persons aged ≥20 years, ages for which NHANES collects education levels for adults.

      NHANES analytic guidance and brief overview for the 2017-March 2020 pre-pandemic data files. National Center for Health Statistics, Centers for Disease Control and Prevention. https://wwwn.cdc.gov/nchs/nhanes/continuousnhanes/overviewbrief.aspx?cycle=2017-2020. Updated June 22, 2021. Accessed July 29, 2022.

      For many young adults, current educational achievement may not reflect final educational achievement. To account for this, a sensitivity analysis was conducted by restricting to participants aged 25–42 years. NCHS provided the poverty income ratio, the ratio of the reported family income to the Department of Health and Human Services poverty guideline during the respective survey year. Replicating the methodology of a recent study,
      • Watson KB
      • Whitfield G
      • Chen TJ
      • Hyde ET
      • Omura JD.
      Trends in aerobic and muscle-strengthening physical activity by race/ethnicity across income levels among U.S. adults, 1998–2018.
      poverty income ratio was stratified as low (<1.5), moderate (1.5–4.0), and high (>4.0). Participants missing a stratification variable value were excluded from the analysis of that variable.

      Measures

      Eligible BMI was defined as 19.0–27.5 kg/m2, a range that closely approximates a military-wide Department of Defense entrance standard.
      U.S. Department of Defense
      Instruction 1308.3: DoD physical fitness and body fat programs procedures.
      This does not exactly demarcate the entrance standard for all applicants because individual Services may issue waivers for candidates not meeting standards,
      U.S. Department of Defense
      Instruction 6130.03, volume 1. Medical standards for military service: appointment, enlistment, or induction.
      may use non-BMI measures to assess body composition, and may establish more stringent standards (but not beyond <25.0 kg/m2).
      U.S. Department of Defense
      Instruction 1308.3: DoD physical fitness and body fat programs procedures.
      Using measured weight and height data in the NHANES examination module, BMI was calculated as the weight in kilograms divided by the square of height in meters and rounded to the nearest tenth place.
      National Center for Health Statistics
      NHANES anthropometry procedures manual.
      Adequate physical activity was defined as reporting at least 300 minutes/week of equivalent moderate-intensity aerobic physical activity from all domains (i.e., leisure time, transportation, and, in NHANES, combined occupational and household). This approximates the amount of physical activity—60 minutes per day, 4‒5 days per week—recommended by the U.S. Army Future Soldier Program to prepare incoming recruits for IMT.
      U.S. Department of the Army
      FM 7-22: holistic health and fitness.
      It also corresponds to the high aerobic guideline of the Physical Activity Guidelines for Americans, second edition.
      HHS
      Physical Activity Guidelines for Americans.
      However, by necessity and by design, this definition does not strictly reflect the U.S. Army recommendation because the example physical activities listed in the NHANES questionnaire

      Physical activity and physical fitness questionnaire. National Center for Health Statistics. http://www.cdc.gov/nchs/data/nhanes/spq-pa.pdf. Updated January 26, 2016. Accessed July 29, 2022.

      do not perfectly overlap with the suggested workouts in the Future Soldier Program.
      U.S. Department of the Army
      FM 7-22: holistic health and fitness.
      All-domain physical activity over the previous 30 days was ascertained from a series of 15 questions in NHANES (Appendix Table 1, available online).

      Physical activity and physical fitness questionnaire. National Center for Health Statistics. http://www.cdc.gov/nchs/data/nhanes/spq-pa.pdf. Updated January 26, 2016. Accessed July 29, 2022.

      To calculate equivalent moderate-intensity duration, vigorous physical activity minutes were multiplied by 2 and added to moderate physical activity minutes.
      HHS
      Physical Activity Guidelines for Americans.
      Beginning in 2017, NHANES restricted the detailed physical activity question set to adults, asking younger participants how many days in the previous week they achieved at least 60 minutes of moderate-to-vigorous intensity physical activity. Accordingly, for those aged 17 years in the 2017–2020 cycle (unweighted n=240), adequate physical activity was defined as ≥60 minutes per day of moderate-to-vigorous physical activity, the youth recommendation in the Physical Activity Guidelines for Americans, second edition.
      HHS
      Physical Activity Guidelines for Americans.
      A sensitivity analysis was performed by excluding participants aged 17 years in the 2017–2020 cycle.
      Table 1Participant Characteristics of the Military-Aged U.S. Population, NHANES 2015–2020
      VariablesPopulation, n (weighted %)
      Gender
       Male2,927 (51.4)
       Female3,037 (48.6)
      Age, years
       17–242,045 (29.8)
       25–291,094 (20.6)
       30–341,107 (20.1)
       35–421,718 (29.5)
      Race and ethnicity
       NH White1,752 (55.2)
       NH Black1,435 (12.7)
       Hispanic1,636 (20.9)
       NH other
      Includes persons who identify as non-Hispanic and any of American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or multiracial.
      1,141 (11.2)
      Education
      Restricted to participants aged 20–42 years.
       High school or less1,918 (35.2)
       Some college1,677 (32.2)
       College graduate1,318 (32.6)
      Family income
      Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
       Low2,064 (28.4)
       Moderate2,039 (39.0)
       High1,151 (32.6)
      Note: Data are restricted to nonpregnant participants aged 17–42 years with available BMI and physical activity data; unweighted n=5,964 for all variables except for education (n=4,913) and family income (n=5,254).
      NH, non-Hispanic; NHANES, National Health and Nutrition Examination Survey.
      a Includes persons who identify as non-Hispanic and any of American Indian or Alaska Native, Asian, Native Hawaiian or Pacific Islander, or multiracial.
      b Restricted to participants aged 20–42 years.
      c Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
      Eligible and active was defined as having an eligible BMI of 19.0–27.5 kg/m2 and reporting an adequate physical activity level of at least 300 minutes/week of equivalent moderate-intensity activity. Given the importance of young adults to the military, eligible and active prevalence was calculated by sociodemographic category within the subpopulation aged 17–24 years.

      Statistical Analysis

      Data from the 2015–2016 and 2017–2020 NHANES cycles were merged. To account for the 5.2-year surveillance period, the 2015–2016 survey weights were multiplied by 2/5.2, and the 2017–2020 survey weights were multiplied by 3.2/5.2, as recommended by NCHS.

      NHANES analytic guidance and brief overview for the 2017-March 2020 pre-pandemic data files. National Center for Health Statistics, Centers for Disease Control and Prevention. https://wwwn.cdc.gov/nchs/nhanes/continuousnhanes/overviewbrief.aspx?cycle=2017-2020. Updated June 22, 2021. Accessed July 29, 2022.

      Survey weights from the examination module were used because there were fewer observations for examinations than for interviews in both cycles.
      Prevalences of eligible BMI, adequate physical activity, and eligible and active status were calculated for the population and for subpopulations by gender, age category, race/ethnicity, education, and family income. Prevalence within subpopulations was compared using the Satterthwaite-adjusted F-test, with significance established at α of 0.05. Prevalence estimates and 95% CI were obtained using Taylor Series Linearization methods. Estimates based on low sample sizes or wide Korn‒Graubard CI were suppressed, according to NCHS data presentation standards.
      • Parker JD
      • Talih M
      • Malec DJ
      • et al.
      National Center for Health Statistics data presentation standards for proportions.
      To account for the complex survey design, analyses were conducted in SAS-callable SUDAAN, release 11.0.0 (RTI International, Research Triangle Park, NC). The STROBE statement on cross-sectional studies was used to develop this report.
      • von Elm E
      • Altman DG
      • Egger M
      • et al.
      The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.

      RESULTS

      After excluding eligible participants missing measured weight and height values (unweighted n=45) or complete physical activity values (unweighted n=75), the unweighted analytic sample size was 5,964. More than half of the weighted sample was male (51.4%) and non-Hispanic White (55.2%). By sociodemographic category, pluralities were aged 17–24 years (29.8%), had completed high school or less (35.2%), and reported a moderate family income (39.0%) (Table 1).
      Weighted prevalence of an eligible BMI was 47.3% (95% CI=44.6, 49.9), and that of an ineligible BMI was 52.7% (95% CI=50.1, 55.4), with BMI <19.0 kg/m2 comprising 3.9% and BMI >27.5 kg/m2 comprising 48.9% of the population. BMI eligibility was similar among males (47.2%) and females (47.3%) (p=0.994) but varied significantly by age (p<0.001), race/ethnicity (p<0.001), education (p<0.001), and income (p=0.030). Within the population aged 17–24 years, 55.4% were BMI eligible, 7.3% had a low BMI, and 37.3% had a high BMI (Table 2).
      Table 2Eligible and Ineligible BMI Prevalence of the Military-Aged U.S. Population, NHANES 2015–2020
      VariablesEligible BMI (19.0–27.5 kg/m2), % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      Ineligible BMI
      <19.0 kg/m2, % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      >27.5 kg/m2, % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      Total47.3 (44.6, 49.9)3.9 (3.3, 4.6)48.9 (46.2, 51.5)
      Gender
       Male47.2 (42.9, 51.6)0.9943.1 (2.4, 4.0)0.02549.6 (45.4, 53.9)0.015
       Female47.3 (44.5, 50.1)4.7 (3.7, 5.9)48.0 (45.4, 50.7)
      Age, years
       17–2455.4 (51.8, 58.9)<0.0017.3 (5.9, 8.9)37.3 (33.9, 40.9)<0.001
       25–2949.4 (44.4, 54.4)4.7 (2.9, 7.5)45.9 (40.6, 51.4)
       30–3443.7 (39.2, 48.2)54.5 (50.0, 59.0)
       35–4240.0 (36.9, 43.3)58.6 (55.0, 62.2)
      Race/ethnicity
       NH White49.4 (45.6, 53.2)<0.0014.1 (3.1, 5.3)0.36646.5 (42.8, 50.3)0.043
       NH Black43.2 (39.8, 46.6)3.7 (2.4, 5.7)53.1 (49.8, 56.5)
       Hispanic39.6 (36.6, 42.7)3.0 (2.2, 4.3)57.3 (53.9, 60.7)
       NH other55.5 (51.4, 59.4)4.9 (3.6, 6.6)39.6 (35.8, 43.6)
      Education
      Restricted to participants aged 20–42 years.
       High school or less42.2 (38.9, 45.6)<0.0013.6 (2.5, 5.2)0.90554.2 (50.7, 57.6)0.743
       Some college40.4 (36.7, 44.2)3.4 (2.5, 4.6)56.2 (52.6, 59.8)
       College graduate54.2 (49.3, 59.1)3.2 (1.9, 5.4)42.6 (37.8, 47.5)
      Family income
      Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
       Low43.8 (41.3, 46.5)0.0304.9 (3.5, 6.8)0.02051.3 (48.3, 54.3)0.071
       Moderate44.4 (41.3, 47.7)4.5 (3.3, 6.2)51.0 (47.6, 54.5)
       High52.2 (45.7, 58.6)2.1 (1.4, 3.0)45.8 (39.2, 52.5)
      Note: Boldface indicates statistical significance (p<0.05).
      Values are weighted percentages on the basis of nonpregnant persons aged 17–42 years; unweighted n=5,964 for all variables except for education (n=4,913) and family income (n=5,254). Weighted percentages may not sum to 100% because of rounding. - denotes data suppressed because of small sample size or wide Korn-Graubard CI.
      NH, non-Hispanic; NHANES, National Health and Nutrition Examination Survey.
      a Based on the Satterthwaite adjusted F-test.
      b Restricted to participants aged 20–42 years.
      c Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
      Among those with an eligible BMI (unweighted n=2,812), weighted prevalence of adequate physical activity was 72.5% (95% CI=70.4, 74.5), and that of inadequate physical activity was 27.5% (95% CI=25.5, 29.6). Adequate physical activity was higher among males than among females (p=0.001) and varied significantly by race/ethnicity (p<0.001); it was similar by age (p=0.186), education (p=0.523), and income (p=0.553). Among those ineligible owing to low and high BMI, respective weighted prevalence of adequate physical activity was 63.7% and 63.5%. Irrespective of BMI, 67.7% of the population was adequately physically active (Table 3).
      Table 3Adequate Physical Activity Prevalence by BMI Eligibility of the Military-Aged U.S. Population, NHANES 2015–2020
      VariableEligible BMI (19.0–27.5 kg/m2), % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      Ineligible BMITotal, % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      <19.0 kg/m2, % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      >27.5 kg/m2, % (95% CI)p-value
      Based on the Satterthwaite adjusted F-test.
      Total72.5 (70.4, 74.5)63.7 (56.3, 70.5)63.5 (60.9, 65.9)67.7 (66.1, 69.4)
      Gender
       Male77.8 (74.4, 80.9)0.00171.0 (56.9, 82.0)0.12872.0 (68.7, 75.1)<0.00174.7 (72.1, 77.2)<0.001
       Female66.9 (62.8, 70.7)58.5 (50.3, 66.3)54.1 (50.5, 57.7)60.4 (58.1, 62.6)
      Age, years
       17–2474.2 (70.3, 77.8)0.18658.2 (49.8, 66.1)66.7 (63.4, 69.9)0.03270.3 (67.5, 72.9)0.003
       25–2973.6 (68.4, 78.2)66.4 (61.4, 71.1)70.4 (66.7, 73.9)
       30–3474.2 (68.2, 79.4)65.3 (59.5, 70.7)69.3 (65.2, 73.0)
      35–4267.9 (63.2, 72.3)58.6 (53.8, 63.2)62.3 (59.0, 65.5)
      Race/ethnicity
       NH White77.8 (74.5, 80.7)<0.00172.2 (61.6, 80.7)64.3 (60.1, 68.3)0.43971.3 (68.5, 73.9)<0.001
       NH Black67.3 (63.3, 71.0)63.2 (50.4, 74.3)63.6 (60.4, 66.7)65.2 (62.6, 67.7)
       Hispanic68.6 (63.4, 73.5)63.5 (59.1, 67.7)65.1 (62.0, 68.1)
       NH other59.1 (55.0, 63.1)58.4 (51.4, 65.0)58.2 (53.9, 62.5)
      Education
      Restricted to participants aged 20–42 years.
       High school or less73.2 (70.0, 76.3)0.52373.3 (60.9, 82.8)64.4 (60.4, 68.2)0.05468.5 (65.7, 71.1)0.108
       Some college76.3 (71.5, 80.6)75.2 (60.6, 85.7)68.5 (64.6, 72.2)71.9 (69.0, 74.7)
       College graduate73.4 (69.1, 77.3)59.2 (51.9, 66.1)67.0 (63.1, 70.7)
      Family income
      Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
       Low72.4 (68.7, 75.9)0.55360.5 (47.0, 72.5)61.2 (57.9, 64.4)0.21366.1 (64.0, 68.1)0.435
       Moderate71.6 (67.9, 75.0)66.3 (62.2, 70.2)68.8 (65.5, 72.0)
       High73.4 (69.1, 77.3)59.2 (51.9, 66.1)67.0 (63.1, 70.7)
      Note: Boldface indicates statistical significance (p<0.05).
      Data are weighted percentages on the basis of nonpregnant persons aged 17–42 years; unweighted n=5,964 for all variables except for education (n=4,913) and family income (n=5,254), defined as reporting ≥300 minutes/week of moderate-intensity physical activity or ≥150 minutes/week of vigorous-intensity physical activity or the equivalent combination from all domains (or for those aged 17 years in the 2017–2020 data, reporting ≥60 minutes/day of moderate-intensity physical activity daily). ‒ denotes data suppressed owing to small sample size or wide Korn‒Graubard CI.
      NH, non-Hispanic; NHANES, National Health and Nutrition Examination Survey; PA, physical activity.
      a Based on the Satterthwaite adjusted F-test.
      b Restricted to participants aged 20–42 years.
      c Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
      Overall, 34.3% (95% CI=31.9, 36.7) of participants were eligible and active. The prevalence was higher among males than among females (p=0.047), was lower with older age (p<0.001), and varied significantly by race/ethnicity (p<0.001), education (p=0.001), and income (p=0.036). Among those aged 17–24 years, 41.1% were eligible and active (Table 4). Within the young adult population, prevalence differed by race/ethnicity (Appendix Table 2, available online).
      Table 4Combined Prevalence of Eligible and Active Status of the Military-Aged U.S. Population, NHANES 2015–2020
      VariablesEligible and active,
      Defined as BMI of 19.0–27.5 kg/m2 and reporting ≥300 minutes/week of moderate-intensity PA or ≥150 minutes/week of vigorous-intensity PA or the equivalent combination from all domains (or for those aged 17 years in the 2017–2020 data, reporting ≥60 minutes/day of moderate-intensity PA daily).
      % (95% CI)
      Not eligible and active,
      Defined as BMI <19.0 or >27.5 kg/m2 or reporting <300 minutes/week of moderate-intensity PA or <150 minutes/week of vigorous-intensity PA or the equivalent combination from all domains (or for those aged 17 years in the 2017–2020 data, not reporting ≥60 minutes/day of moderate-intensity PA daily).
      % (95% CI)
      p-value
      Based on the Satterthwaite adjusted F-test.
      Total34.3 (31.9, 36.7)65.7 (63.3, 68.1)
      Gender
       Male36.8 (33.1, 40.6)63.2 (59.4, 66.9)0.047
       Female31.6 (28.5, 34.9)68.4 (65.1, 71.5)
      Age, years
       17–2441.1 (37.1, 45.1)58.9 (54.9, 62.9)<0.001
       25–2936.3 (31.8, 41.1)63.7 (58.9, 68.2)
       30–3432.4 (28.1, 37.0)67.6 (63.0, 71.9)
       35–4227.2 (24.3, 30.2)72.8 (69.8, 75.7)
      Race/ethnicity
       NH White38.4 (34.8, 42.2)61.6 (57.8, 65.2)<0.001
       NH Black29.1 (26.1, 32.1)70.9 (67.9, 73.9)
       Hispanic27.2 (24.3, 30.3)72.8 (69.7, 75.7)
       NH other32.8 (29.8, 35.8)67.2 (64.2, 70.2)
      Education
      Restricted to participants aged 20–42 years.
       High school or less30.9 (28.1, 33.9)69.1 (66.1, 71.9)0.001
       Some college30.8 (27.2, 34.7)69.2 (65.3, 72.8)
       College graduate39.8 (35.5, 44.2)60.2 (55.8, 64.5)
      Family income
      Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
       Low31.8 (29.0, 34.6)68.2 (65.4, 71.0)0.036
       Moderate31.8 (29.3, 34.5)68.2 (65.5, 70.7)
       High38.8 (32.9, 45.0)61.2 (55.0, 67.1)
      Note: Boldface indicates statistical significance (p<0.05).
      Values are weighted percentages on the basis of nonpregnant persons aged 17–42 years; unweighted n=5,964 for all variables except for education (n=4,913) and family income (n=5,254).
      NH, non-Hispanic; NHANES, National Health and Nutrition Examination Survey; PA, physical activity.
      a Defined as BMI of 19.0–27.5 kg/m2 and reporting ≥300 minutes/week of moderate-intensity PA or ≥150 minutes/week of vigorous-intensity PA or the equivalent combination from all domains (or for those aged 17 years in the 2017–2020 data, reporting ≥60 minutes/day of moderate-intensity PA daily).
      b Defined as BMI <19.0 or >27.5 kg/m2 or reporting <300 minutes/week of moderate-intensity PA or <150 minutes/week of vigorous-intensity PA or the equivalent combination from all domains (or for those aged 17 years in the 2017–2020 data, not reporting ≥60 minutes/day of moderate-intensity PA daily).
      c Based on the Satterthwaite adjusted F-test.
      d Restricted to participants aged 20–42 years.
      e Defined by the poverty income ratio: low, <150%; moderate, 150%–400%; high, >400%.
      Among participants aged 25–42 years (unweighted n=3,918), the most common education level was college graduate (weighted prevalence=36.4%). This slightly changed the outcome prevalence: 37.9% of college graduates in this age group were eligible and active, compared with 39.8% in the full sample (Appendix Table 3, available online). Excluding the subset of participants aged 17 years in the 2017–2020 NHANES cycle, adequate physical activity prevalence was 69.3%, and eligible and active prevalence was 34.9%—both slightly higher than in the full sample (Appendix Table 4, available online).

      DISCUSSION

      Of the military-aged U.S. civilian population, 47.3% had an eligible BMI for military entrance. Among those eligible by BMI, 72.5% engaged in an adequate level of physical activity. Accounting for both BMI and physical activity, only 34.3% were BMI eligible and active. This is the first military preparedness study incorporating both anthropometric and physical activity metrics.
      The estimate for body composition ineligibility in this study exceeds those in previous studies. Applying the 2-stage screening method used by the U.S. Army then,

      Instruction 1308.3: DoD physical fitness and body fat programs procedures [obsolete]. U.S. Department of Defense. https://biotech.law.lsu.edu/blaw/dodd/corres/html/13083.htm. Updated 2002. Accessed July 29, 2022.

      Cawley and Maclean documented a dramatic rise in the population aged 17–42 years who did not meet body composition standards: whereas 4% of males and 16% of females exceeded standards in NHANES I (conducted from 1971 to 1975), 12% and 35% exceeded the standards in the 2007–2008 NHANES cycle.
      • Cawley J
      • Maclean JC.
      Unfit for service: the implications of rising obesity for U.S. military recruitment.
      In a distinct analysis using 2001–2004 NHANES data and applying Service-specific standards in use then, excessive BMI ineligibility of the population aged 17–42 years ranged from 31% for the U.S. Marine Corps to 40% for the U.S. Air Force.
      • Yamane GK.
      Obesity in civilian adults: potential impact on eligibility for U.S. military enlistment.
      Methodologic differences—some of which reflect changes in how the Department of Defense assesses body composition—prevent direct comparisons between studies. However, the upward trend in ineligibility running through these 3 studies mirrors the increase in population prevalence of obesity.
      • Fryar CD
      • Carroll MD
      • Afful J.
      Prevalence of overweight, obesity, and severe obesity among children and adolescents aged 2–19 years: United States, 1963–1965 through 2017–2018.
      ,
      • Ogden CL
      • Fryar CD
      • Martin CB
      • et al.
      Trends in obesity prevalence by race and Hispanic origin −1999–2000 to 2017–2018.
      Similar to these studies,
      • Cawley J
      • Maclean JC.
      Unfit for service: the implications of rising obesity for U.S. military recruitment.
      ,
      • Yamane GK.
      Obesity in civilian adults: potential impact on eligibility for U.S. military enlistment.
      the current analysis includes the entire age-eligible U.S. population. However, reports on military preparedness often focus on young adults.

      Mission: readiness. Ready, willing, and unable to serve. Strong America.November 5, 2009. https://www.strongnation.org/articles/21-ready-willing-and-unable-to-serve. Accessed July 29, 2022.

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      ,
      • Nolte R
      • Franckowiak SC
      • Crespo CJ
      • Andersen RE
      U.S. military weight standards: what percentage of U.S. young adults meet the current standards?.
      ,
      Centers for Disease Control and Prevention
      Unfit to serve: obesity is impacting national security.
      This is understandable given their disproportionate representation in the enlisted active component of the U.S. military: individuals aged 17–24 years account for 88% of applicants
      U.S. Department of Defense
      Appendix A: active component applicant tables.
      and 47% of current service members.
      U.S. Department of Defense
      Office of Under Secretary of defense for personnel and readiness. Population representation in the military services: fiscal year. Summary report (Appendix B: Active Component Accessions and Force).
      A recent report asserts that 31% of the U.S. population aged 17–24 years would be disqualified from military service, if they chose to join, because of obesity.

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      For the same age group in this study, 37% were ineligible on the basis of high BMI, and 59% were not eligible and active. Some fraction of the eligible cohort would not meet other military entrance requirements (e.g., by virtue of a criminal record

      32 CFR 66.6: Enlistment, Appointment, and Induction Criteria. Amended July 1, 2022. https://www.ecfr.gov/current/title-32/subtitle-A/chapter-I/subchapter-D/part-66/section-66.6. Accessed July 29, 2022.

      or medically disqualifying condition
      U.S. Department of Defense
      Instruction 6130.03, volume 1. Medical standards for military service: appointment, enlistment, or induction.
      ).
      This study also draws attention to the military preparedness repercussions of the inequitable distribution of unhealthy weight and inadequate physical activity. Fewer than 30% of the non-Hispanic Black and Hispanic populations were eligible and active, and prevalence was lower in noncollege graduates than in their peers. Addressing the root causes of health disparities is an established public health priority
      • Hacker KA
      • Briss PA.
      An ounce of prevention is still worth a pound of cure, especially in the time of COVID-19.
      that may benefit the U.S. military by expanding enlistment opportunities within underserved populations. The active duty force (n=1.33 million) has lower proportions of persons identifying as non-Hispanic White (55.6% vs 62.1%) and who hold a college degree (22.5% vs 40.6%) than the nation's civilian labor force (n=162 million).
      U.S. Department of Defense
      Office of the deputy assistant Secretary of Defense for military community and family policy; 2020 Demographics Profile of the Military Community.
      ,
      U.S. Bureau of Labor Statistics
      Report 1082: Labor Force Characteristics by Race and Ethnicity.
      This diverse workforce positions the U.S. military, in addition to its national defense function, as an important institution for upward mobility.
      Equitable strategies to improve nutrition and physical activity can reduce the disparities identified in this study while increasing overall preparedness. Many of these strategies have been synthesized in U.S. Surgeon General reports that endorse access to healthy foods
      HHS
      The Surgeon General's Vision for a Healthy and Fit Nation.
      and to safe and convenient places for walking,
      HHS
      Step it up! The Surgeon General's Call to Action to Promote Walking and Walkable Communities.
      with an emphasis on resource-limited communities.
      • Brownson RC
      • Baker EA
      • Housemann RA
      • Brennan LK
      • Bacak SJ.
      Environmental and policy determinants of physical activity in the United States.
      Evidence-based strategies are also promoted in Active People, Healthy Nation, an initiative by the Centers for Disease Control and Prevention to increase physical activity through individual and community supports.
      • Schmid TL
      • Fulton JE
      • McMahon JM
      • Devlin HM
      • Rose KM
      • Petersen R.
      Delivering physical activity strategies that work: active People, Healthy NationSM.
      Municipal leaders can use the Centers for Disease Control and Prevention's Active Communities Tool to enhance street design and connectivity, expand pedestrian and bicycle infrastructure, and extend access to parks and recreational facilities.
      Centers for Disease Control and Prevention
      The active communities tool (ACT): an action planning Guide and assessment modules to improve community built environments to promote physical activity.
      As others have asserted,

      Mission: readiness. Too fat to fight. Strong America.April 10, 2010. https://www.strongnation.org/articles/23-too-fat-to-fight. Accessed July 29, 2022.

      ,

      Mission: readiness. Unhealthy and unprepared. Strong America.October 10, 2018. https://www.strongnation.org/articles/737-unhealthy-and-unprepared. Accessed July 29, 2022.

      ,
      • Tompkins E.
      Obesity in the United States and effects on military recruiting.
      ,

      Koehlmoos TP, Banaag A, Madsen CK, Adirim T. Child health as a national security issue: obesity and behavioral health conditions among military children. Health Aff (Millwood). 2020;39(10):1719–1727. https://doi.org/10.1377/hlthaff.2020.00712.

      the military recruitment challenges of tomorrow may be best addressed today by encouraging healthy diet and physical activity among children and adolescents—habits which often continue into adulthood and may protect against obesity later in life.
      • O'Connor EA
      • Evans CV
      • Burda BU
      • Walsh ES
      • Eder M
      • Lozano P.
      U.S. Preventive Services Task Force evidence syntheses. screening for obesity and interventions for weight management in children and adolescents: a systematic evidence review for the U.S. Preventive Services Task Force.
      Challenges abound in the U.S., including racial and ethnic disparities in the prevalence of childhood obesity and inadequate physical activity
      • Chen TJ
      • Watson KB
      • Michael SL
      • Carlson SA.
      Sex-stratified trends in meeting physical activity guidelines, participating in sports, and attending physical education among U.S. adolescents, Youth Risk Behavior survey 2009–2019.
      and reduced access to nutritious food
      HHS
      The Surgeon General's Vision for a Healthy and Fit Nation.
      ,
      • Cooksey-Stowers K
      • Schwartz MB
      • Brownell KD.
      Food swamps predict obesity rates better than food deserts in the United States.
      and safe spaces for physical activity
      HHS
      Step it up! The Surgeon General's Call to Action to Promote Walking and Walkable Communities.
      ,
      • Burdette HL
      • Whitaker RC.
      A national study of neighborhood safety, outdoor play, television viewing, and obesity in preschool children.
      in lower-income communities. These multifaceted problems require engagement by parents, schools, communities, industry, and healthcare providers. The U.S. Preventive Services Task Force recommends universal obesity screening for children aged ≥6 years and referring those with obesity to comprehensive behavioral interventions.
      • Grossman DC
      • Bibbins-Domingo K
      U.S. Preventive Services Task Force
      Screening for obesity in children and adolescents: U.S. Preventive Services Task Force recommendation statement.
      The Community Preventive Services Task Force outlines several evidence-based interventions to prevent and reduce obesity

      CPSTF findings for obesity. Community Preventive Services Task Force. https://www.thecommunityguide.org/content/task-force-findings-obesity. Updated 2021. Accessed July 29, 2022.

      and to promote physical activity

      CPSTF findings for physical activity. Community Preventive Services Task Force. https://www.thecommunityguide.org/content/task-force-findings-physical-activity. Updated April 19, 2022. Accessed July 29, 2022.

      among youth. Early life solutions include devices to track and reduce recreational screen time
      • Ramsey Buchanan L
      • Rooks-Peck CR
      • Finnie RKC
      • et al.
      Reducing recreational sedentary screen time: a Community Guide systematic review.
      ; traffic-mitigation strategies to increase walking to and from school
      • Omura JD
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      • Watson KB
      • Sliwa SA
      • Fulton JE
      • Carlson SA.
      Prevalence of children walking to school and related barriers - United States, 2017.
      ; and increased opportunities for physical activity before, during, and after school.
      Centers for Disease Control and Prevention
      Increasing physical education and physical activity: a framework for schools.
      ,
      • Masini A
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      Limitations

      The strength of this study is its large, nationally representative sample, but its findings are subject to at least 5 limitations. First, the Service-agnostic BMI range may not strictly correspond to eligibility for military entrance. It does not account for medical waivers, more stringent Service-specific cutoffs (e.g., a BMI threshold of 25.0 kg/m2 for young female U.S. Army candidates
      U.S. Department of the Army
      Army Regulation: The Army Body Composition Program.
      ), or alternative screening techniques for body composition. However, in the population aged 20–39 years, BMI is highly correlated with other modalities that estimate body fat percentage.
      • Flegal KM
      • Shepherd JA
      • Looker AC
      • et al.
      Comparisons of percentage body fat, body mass index, waist circumference, and waist-stature ratio in adults.
      Second, physical activity participation was self-reported and limited to bouts of at least 10 minutes. Despite susceptibility to recall and social desirability biases, self-reported pre-entrance physical activity has been strongly associated with multiple performance measures among military recruits.
      • Trone DW
      • Cipriani DJ
      • Raman R
      • Wingard DL
      • Shaffer RA
      • Macera CA.
      The association of self-reported measures with poor training outcomes among male and female U.S. Navy recruits.
      ,
      • Gubata ME
      • Cowan DN
      • Bedno SA
      • Urban N
      • Niebuhr DW.
      Self-reported physical activity and preaccession fitness testing in U.S. Army applicants.
      Research also suggests that failure to capture shorter-activity bouts would not dramatically alter these findings.
      • Ussery EN
      • Watson KB
      • Carlson SA.
      The influence of removing the ten-minute bout requirement on national physical activity estimates.
      Third, educational achievement is not static in this cohort of mostly young adults and was not collected for those aged 17–19 years in the later NHANES. Fourth, assessment of physical activity for participants aged 17 years changed between NHANES cycles. To address these latter 2 issues, sensitivity analyses were conducted to provide outcome prevalence under different restriction parameters.
      Finally, physical activity participation does not precisely reflect physical fitness.
      U.S. Department of the Army
      FM 7-22: holistic health and fitness.
      NHANES was selected because it contains objectively measured BMI and all domains of aerobic physical activity. Including transportation, occupational, and household physical activity may capture individuals who are aerobically prepared for IMT by virtue of physically demanding commutes or occupations but who would be miscategorized by surveillance systems that limit to the leisure-time domain.
      • Whitfield GP
      • Ussery EN
      • Carlson SA.
      Combining data from assessments of leisure, occupational, household, and transportation physical activity among U.S. adults, NHANES 2011–2016.
      Although both endurance and muscular fitness are required for military training, no surveillance system includes all pertinent information. If the study were repeated with leisure-time aerobic and muscle-strengthening activity data in the National Health Interview Survey, the prevalence of adequate physical activity may be even lower. In 2018, just 34% of participants aged 18–24 years reported ≥150 minutes/week of equivalent moderate-intensity physical activity and ≥2 episodes/week of muscle-strengthening activity.
      • Hyde ET
      • Whitfield GP
      • Omura JD
      • Fulton JE
      • Carlson SA.
      Trends in meeting the physical activity guidelines: muscle-strengthening alone and combined with aerobic activity, United States, 1998–2018.

      CONCLUSIONS

      Between 2015 and 2020, nearly half of the military-aged U.S. population was eligible to enter the military on the basis of their BMI, and only 1 in 3 was both BMI eligible and adequately active. This is the first military preparedness study that incorporates anthropometric-based eligibility and physical activity. Improving the health of this population and thereby expanding the pool of eligible military applicants require commitment from sectors beyond public health. Upstream efforts can help, including behavioral education, built environment, and policy approaches that promote healthy eating and physical activity. Continued innovation and collaboration may address the root causes of the health inequities reported in this paper.
      • Hacker KA
      • Briss PA.
      An ounce of prevention is still worth a pound of cure, especially in the time of COVID-19.
      In 1960, then President-elect John F. Kennedy described our increasing lack of physical fitness as a menace to our security and summoned a national response.
      • Kennedy JF.
      Sport at the new frontier: the soft American.
      Six decades later, this study contributes new evidence to the ongoing dialogue concerning population health and national security.

      ACKNOWLEDGMENTS

      The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention, the Uniformed Services University of the Health Sciences, the U.S. Air Force, the U.S. Department of Defense, or the U.S. Government.
      The Centers for Disease Control and Prevention supported the staff responsible for the design and conduct of the study; the collection, analysis, and interpretation of the data; the preparation, review, and approval of the manuscript; and the decision to submit the manuscript for publication.
      Some of these findings were presented as a poster at the American College of Sports Medicine 2022 Annual Meeting & World Congress.
      BW and DB report membership on the Military Settings Sector Committee, National Physical Activity Plan, Physical Activity Alliance, Washington, DC.
      No financial disclosures were reported by the authors of this paper.

      CRediT AUTHOR STATEMENT

      Bryant Webber: Conceptualization, Data Curation, Formal Analysis, Methodology, Writing – Original Draft. Daniel Bornstein: Conceptualization, Investigation, Writing – Review and Editing. Patricia Deuster: Investigation, Writing – Review and Editing. Francis O'Connor: Investigation, Writing – Review and Editing. Sohyun Park: Investigation, Writing – Review and Editing. Kenneth Rose: Investigation, Resources, Writing – Review and Editing. Geoffrey Whitfield: Supervision, Writing – Review and Editing

      Appendix. SUPPLEMENTAL MATERIAL

      REFERENCES

      1. 32 CFR 66.6: Enlistment, Appointment, and Induction Criteria. Amended July 1, 2022. https://www.ecfr.gov/current/title-32/subtitle-A/chapter-I/subchapter-D/part-66/section-66.6. Accessed July 29, 2022.

      2. Instruction 1304.26: qualification standards for enlistment, appointment, and induction. U.S. Department of Defense. https://www.esd.whs.mil/Portals/54/Documents/DD/issuances/dodi/130426p.pdf?ver=2018-10-26-085822-050. Updated October 26, 2018. Accessed July 29, 2022.

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