Are the Recommended Levels of Moderate-to-Vigorous Aerobic Activity and Resistance Training Inversely Associated with Frailty and Mortality?

Objectives

To examine the association of meeting the moderate-to-vigorous physical activity (MVPA) and resistance training (RT) components of the physical activity guidelines with frailty and mortality and to determine if these associations vary by age and sex.

Design

Observational study.

Setting and Participants

Secondary analysis of 17,716 community-dwelling individuals [46 ± 19 years (range: 20-85 years), 52.2% female] from the National Health and Nutrition Examination Survey (NHANES) (cycles 1999-2006) who had available Frailty Index, mortality, and self-reported physical activity data.

Methods

Self-reported MVPA (≥150 minutes/wk) and RT (≥2 days/wk) levels were used to divide participants into Combined (both met), MVPA Only, RT Only, or Inactive (neither met) groups. Frailty was measured with a 46-item Frailty Index (FI), and all-cause mortality was obtained using National Death Index data. Group differences were explored using analyses of variance. Associations between MVPA and/or RT with (1) frailty and (2) mortality used covariate-adjusted multiple linear regression and Cox proportional hazards models, respectively.

Results

A total of 1878 (10.6%) people were included in the Combined group, 3741 (21.1%) in the MVPA Only group, 1257 (7.1%) in the RT Only group, and 10,840 (61.2%) in the Inactive group. Older females needed to engage in MVPA to experience a beneficial effect on frailty, whereas males benefited from engaging in either or both types of activity regardless of age. Females at the lowest frailty level [hazard ratio (HR) 0.65, 95% CI 0.46-0.93] and frail males (HR 0.72, 95% CI 0.59-0.88) in the Combined group had a lower risk of mortality compared to the Inactive group.

Conclusions and Implications

There is a lower association with frailty and mortality when achieving MVPA or RT guidelines alone, although sex and age differences demonstrate that MVPA is especially critical as females age.