Associations between sedentary behavior and allostatic load: The 1970 British Cohort Study

Chronic/repeated exposure to psychological stressors can induce high allostatic load (AL), or multisystem physiological dysregulation, which increases cardiometabolic disease (CMD) risk. While moderate-to-vigorous physical activity (MVPA) is inversely related to AL, associations with sedentary behavior (SB) remain unclear. This study tested associations between multiple activPAL-derived SB metrics-total SB, SB breaks, and SB bout duration-and AL among middle-aged adults.

Participants (n = 8581; 46.8 ± 0.7 years; 52% female) represented the 1970 British Cohort Study (2016-2018 sweep), where SB was assessed via activPAL3 accelerometry to derive total SB time (h/day), SB break rate (# sit-to-stand transitions/hr of SB time), and mean SB bout duration (min/bout). Seven AL biomarkers were assessed: inflammatory (C-reactive protein), cardiovascular (systolic blood pressure [BP], diastolic BP, heart rate), and metabolic (HDL, total cholesterol, triglycerides). High AL was defined as ≥ 2 biomarkers in the highest-risk quartile. Cross-sectional logistic regression models tested associations between SB metrics and AL, adjusting for MVPA and other covariates.

There were 5% higher odds of high AL per additional hour/day of total SB (OR=1.05; 95% CI: 1.01-1.09). Each additional break/SB hour was associated with 3% lower odds of high AL (OR=0.97; 95% CI: 0.94-0.99). Mean SB bout duration was not significantly associated with AL in fully adjusted models.

Higher total SB and fewer breaks per sedentary hour were associated with greater AL. If longitudinal and experimental studies confirm causality and clinical relevance, reducing total SB time and increasing SB interruptions could be feasible strategies to reduce AL and mitigate stress-induced CMD risk.