Sedentary behaviour and chronic stress in old age: a cross-sectional analysis of TV viewing and hair cortisol concentrations

Purpose: Several studies have reported a positive association between sedentary behaviour and perceived stress, but none using a population-based sample have examined this relationship using an objective measure of stress exposure. The aim of this study was therefore to analyse the association between sedentary behaviour (operationalised as daily TV viewing time) and levels of cortisol in hair (an objective measure of chronic stress) using data from a large population-based sample of older adults. Method: Analyses used cross-sectional data from older adults (≥50 years) participating in Wave 6 (2012/13) of the English Longitudinal Study of Ageing. Hair cortisol concentrations were determined from the scalp‐nearest 2cm hair segment. TV viewing time was self-reported and categorised as <2, 2<4, 4<6, or ≥6 hours/day. Covariates included age, sex, ethnicity, education, wealth, limiting long-standing illness, cardiovascular disease, diabetes, smoking status, alcohol intake, physical activity, body mass index, and depressive symptoms. Results: The sample comprised 3,555 men and women, of whom 284 (8.0%) reported watching less than 2 hours of TV per day, 1,160 (32.6%) 2-4 hours, 1,079 (30.4%) 4-6 hours, and 1,032 (29.0%) ≥6 hours. Mean hair cortisol concentrations for those spending <2, 2<4, 4<6, and ≥6 hours per day watching TV were 0.862, 0.880, 0.889, and 0.934 log pg/mg, respectively. Differences between groups were not statistically significant in unadjusted (p=.088) or adjusted (p=.663) models. Conclusion: In a large sample of older adults in England, self-reported sedentary behaviour was not associated with a biomarker of chronic stress. However, future longitudinal research should be undertaken to confirm/refute this finding.