Association of Muscle-Strengthening and Aerobic Physical Activity With Mortality in US Adults Aged 65 Years or Older

The Physical Activity Guidelines for Americans, second edition, recommends that older adults (aged ≥65 years) participate in balance training, muscle-strengthening activities (MSAs; ≥2 days per week), and moderate to vigorous aerobic physical activity (MVPA; ≥150 minutes per week at moderate intensity, ≥75 minutes per week at vigorous intensity, or an equivalent combination).¹ Evidence for MSAs in older adults is mostly based on fall prevention.² This study explored the dose-response association between MSA and all-cause mortality in older adults, independent of and combined with MVPA, and characterized age-stratified associations.

In this cohort study, we assessed self-reported leisure time physical activity and deaths among 1998-2018 National Health Interview Survey (NHIS) participants, using the 2019 linked NHIS and National Death Index mortality files.³ The NHIS is a nationally representative sample of the civilian, noninstitutionalized US population. The survey is approved by the National Center for Health Statistics, and all participants provide verbal consent.⁴ Between June 1 and July 5, 2022, we calculated weekly MVPA as the sum of moderate minutes and doubled vigorous minutes. In addition to the binary guidelines, we defined 4 levels of MSA by weekly episodes (0-1, 2-3, 4-6, and 7-28) and 4 levels of MVPA by weekly minutes (<10, 10-149, 150-300, and >300).¹ We determined hazard ratios and 95% CIs for all-cause mortality using Cox regression, adjusting for sex; age; race and ethnicity; education; marital status; body mass index; smoking; alcohol consumption; and baseline presence of hypertension, heart disease, stroke, diabetes, cancer, chronic obstructive pulmonary disease, and asthma. We tested the proportional hazards assumption with Kaplan-Meier curves and Schoenfeld residuals and tested for interaction between MSA and MVPA on all-cause mortality. Of participants aged 65 years or older at the time of interview and eligible for National Death Index linkage (n = 131 418), we excluded those with incomplete data (n = 7827) and, to mitigate bias and confounding, those who died within 2 years of the interview (n = 8102). We used SAS, version 9.4 (SAS Institute Inc) statistical software to account for NHIS strata, clusters, and weights. This study followed STROBE reporting guidelines.

The 115 489 participants were predominantly women (70 451 [weighted 57.3%] vs 45 038 [42.7%] men), aged 65 to 74 years (64 322 [57.8%]), and White (86 404 [80.4%] vs 13 558 [8.4%] Black, 10 765 [7.3%] Hispanic, and 4762 [3.9%] other). During a mean follow-up of 7.9 years, 44 794 deaths occurred. No interaction was evident between MSA and MVPA categories. Adjusting for MVPA, 2 to 3 and 4 to 6 MSA episodes per week (but not 7 to 28 episodes per week) were associated with a lower hazard of all-cause mortality, compared with fewer than 2 episodes. Adjusting for MSA, 10 to 149, 150 to 300, and more than 300 MVPA minutes per week were associated with a lower hazard of all-cause mortality vs less than 10 minutes per week. Combinations of MSA and MVPA had lower hazard estimates (Table). Meeting both the strength and aerobic guidelines, vs meeting neither, was associated with a lower hazard of all-cause mortality among participants aged 65 to 85 years or older (Figure).

Leisure time MSA and MVPA were independently associated with lower all-cause mortality in this cohort study of US adults aged 65 years or older. By using finer age and physical activity categories, a larger sample, and longer follow-up, we build on earlier studies^5,6 and offer new insights for older adults and their health care professionals. First, the U-shaped dose-response between MSA and mortality, independent of aerobic physical activity, suggests that 2 to 6 episodes per week may be optimal.⁶ Second, the age-stratified associations indicate that current physical activity guidelines are important for all older adults, including those aged 85 years or older. Limitations of these findings are possible unmeasured confounding and biases associated with self-reported physical activity data; nonetheless, this study highlights the mortality benefit of both MSA and MVPA for older adults of any age.

Accepted for Publication: August 30, 2022.

Published: October 17, 2022. doi:10.1001/jamanetworkopen.2022.36778

Open Access: This is an open access article distributed under the terms of the CC-BY License. © 2022 Webber BJ et al. JAMA Network Open.

Corresponding Author: Bryant J. Webber, MD, MPH, Division of Nutrition, Physical Activity, and Obesity, Centers for Disease Control and Prevention, 4770 Buford Hwy, Atlanta, GA 30341 (rhq0@cdc.gov).

Author Contributions: Dr Webber had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Webber, Piercy, Whitfield.

Acquisition, analysis, or interpretation of data: Webber, Hyde, Whitfield.

Drafting of the manuscript: Webber.

Critical revision of the manuscript for important intellectual content: Piercy, Hyde, Whitfield.

Statistical analysis: Webber, Whitfield.

Administrative, technical, or material support: Piercy, Hyde, Whitfield.

Supervision: Whitfield.

Conflict of Interest Disclosures: Mr Hyde reported receiving a grant (5T32-HL-079891-14) from the National Heart, Lung, and Blood Institute outside the submitted work. No other disclosures were reported.

Disclaimer: The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention, the Office of Disease Prevention and Health Promotion, or the US government.