Sedentary behaviour, physical activity and psychobiological stress reactivity: a systematic review

Background: Sedentary behaviour, physical activity, and psychobiological reactivity to acute psychological stress are independent risk factors for cardiovascular disease. Sedentary behaviour and physical activity influence autonomic, haemodynamic, and inflammatory pathways under resting conditions, and these pathways become activated under acute psychological stress. However, it is unclear whether sedentary behaviour and physical activity relate to psychobiological responses to stress. Thus, the aim of this study is to systematically review sedentary behaviour and physical activity in the context of psychobiological reactivity to acute psychological stress.

Methods: Sedentary behaviour, physical activity and psychobiological stress reactivity search terms were combined, and several databases were searched in duplicate. Eligibility criteria included: (1) a validated measure of sedentary behaviour/physical activity; (2) cardiovascular, inflammatory, neuroendocrine, or respiratory markers measured at rest and in response to laboratory-induced acute psychological stressResults: 6084 articles were screened, with 11 included in a narrative synthesis. No studies measured postural components of sedentary behaviour, but 2/4 studies found that markers of sedentary behaviour (e.g., physical inactivity) were associated with elevated heart rate, dysregulated heart rate variability, or lowered cortisol responses to stress. Higher volumes of physical activity were linked to lower HR, cortisol, or immune responses to stress in 4/7 studies.

Conclusions: Extensive methodological variability precludes conclusions from being drawn. This review should be used to guide a more homogeneous and gold-standard literature, which accounts for postural components of sedentary behaviour using inclinometery, and the whole physical activity intensity spectrum using universal and reproducible approaches.