Highlights • This is the first stress reactivity study to measure sedentary behavior with gold standard inclinometry. • Sedentary behavior is related to broader psychobiological responses to psychological stress, independent of physical activity. • Exaggerated reactivity may mechanistically underpin links between sedentary behavior and cardiovascular disease risk. |
Background
Sedentary behavior is a risk factor for cardiovascular disease (CVD), but the underlying mechanisms remain unclear. Exaggerated psychobiological responses to acute psychological stress increase the risk of CVD.
Sedentary behavior is associated with characteristics that may predict broad patterns of psychobiological stress response (e.g., elevated resting blood pressure and systemic inflammation), but it is currently unknown whether sedentary behavior and stress reactivity are directly related.
The objective of this study was to examine associations between device-assessed sedentary behavior and measures of stress reactivity.
Methods
Sixty-one healthy adults used an activPAL (thigh) and ActiGraph (wrist) for seven days to measure habitual levels of sedentary behavior (mean ± SD = 9.96 ± 1.48 h/day) and moderate-to-vigorous physical activity (mean ± SD = 101.82 ± 42.92 min/day).
Participants then underwent stress reactivity testing, where beat-by-beat measurements of salivary cortisol and cardiovascular (e.g., blood pressure, total peripheral resistance), inflammatory (plasma interleukin-6, leukocytes) response were taken. to an 8-minute socially evaluative Paced.
Results
Higher volumes of daily sedentary behavior were associated with greater stress responses for diastolic blood pressure (Β=1.264, 95% CI=0.537—1.990, p = 0.005), total peripheral resistance (Β=40.563, 95% CI) =19.310—61.812, p < 0.001), interleukin-6 (Β=0.219, 95% CI=0.109—0.329, p < 0.001) and cortisol (Β=1.844, 95% CI=1.139—2.549, p < 0.001).
These findings emerged independently of a priori determined covariates, including daily levels of moderate-to-vigorous physical activity and adiposity.
Conclusion
Sedentary behavior assessed by the device is related to increased reactivity to multisystem stress (i.e., cardiovascular, inflammatory, and cortisol), which may be a novel mechanism underlying established links between sedentary behavior and CVD.
Future research may investigate the effects of context-specific sedentary behaviors on stress responses, including interactions with physical activity. Further work should explore whether reducing sedentary behavior attenuates measures of stress reactivity, as this may have clinical relevance for CVD prevention.
Discussion
Exaggerated stress reactivity is characteristic of high sedentary behavior and could be a novel mechanism linking sedentary behavior to CVD. Future work should examine the impact of reducing sedentary behavior on measures of stress reactivity, as this may have clinical relevance for preventing CVD.
