Sedentary behavior, physical activity, and markers of health in older adults

Abstract

Introduction: The purpose of this study was to examine the association between sedentary behavior (SB), cardiometabolic risk factors, and self-reported physical function by level of moderate-vigorous physical activity (MVPA).

Methods: Cross-sectional analysis was completed on 1914 older adults age ≥ 65 yr from the 2003-2006 U.S. National Health and Nutrition Examination Survey. MVPA and SB were derived from ActiGraph accelerometers worn for 1 wk. MVPA was categorized as sufficient to meet the current U.S. guidelines (≥ 150 min · wk(-1)) or not; SB was split into quartiles. Various biomarkers were examined in laboratory analyses and physical exams, and the number of functional limitations was self-reported. Statistical interaction between SB and MVPA on the biomarker associations was the primary analysis, followed by an examination of their independent associations with relevant covariate adjustment.

Results: Average SB was 9.4 ± 2.3 h · d(-1) (mean ± SD), and approximately 35% were classified as sufficiently active. Overall, no significant meaningful statistical interactions were found between SB and MVPA for any of the outcomes; however, strong independent positive associations were found between SB and weight (P < 0.01), body mass index (P < 0.01), waist circumference (P < 0.01), C-reactive protein (P < 0.01), plasma glucose (P = 0.04), and number of functional limitations (P < 0.01) after adjustment for MVPA. Similarly, MVPA was negatively associated with weight (P = 0.01), body mass index (P < 0.01), waist circumference (P < 0.01), diastolic blood pressure (P = 0.04), C-reactive protein (P < 0.01), and number of functional limitations (P < 0.01) after adjustment for SB.

Conclusions: The results suggest that sufficient MVPA did not ameliorate the negative associations between SB and cardiometabolic risk factors or functional limitations in the current sample and that there was independence on a multiplicative scale in their associations with the outcomes examined. Thus, older adults may benefit from the joint prescription to accumulate adequate MVPA and avoid prolonged sitting.

Conflict of interest statement

CONFLICT OF INTEREST

The authors have no conflict of interest to declare

Figures

Figure 1. Time spent in sedentary behavior by level of physical activity

Sufficiently active is defined as ≥150 minutes/week of MVPA in bouts of at least 10 minutes. The proportion of each activity group by hours/day spent in sedentary behavior is plotted.

Figure 2. Independent associations between sedentary behavior, physical activity, and physical function

Models included both SB and sufficient/insufficient MVPA and were additionally adjusted for age, gender, ethnicity, education, income, marital status, alcohol consumption, current smoking status, cardiovascular disease, BMI, and accelerometer wear time. Quartiles of SB were: ≥10.64, 10.63–9.18, 9.17–7.93, and 0–7.92 hours/day. Sufficiently active is defined as ≥150 minutes/week of MVPA in bouts of at least 10 minutes.