Interactions between sedentary behaviour, moderate-vigorous intensity physical activity and acute psychological stress-induced inflammatory responses

Introduction: Psychological stress, physical activity (PA) and sedentary behaviour (SB) are modifiable risk factors for cardiovascular disease (CVD), possibly through altering one’s inflammatory profile. The links between inflammatory responses to acute psychological stress and habitual moderate-vigorous physical activity (MVPA) levels or SB volume is not clear. We explored the relationships in the magnitude of inflammatory responses to passive and active psychological stress with habitual MVPA and SB levels.

Methods: Eighty-eight healthy participants completed this study. Habitual MVPA and SB volume were measured over one week using wearable devices. The main trial consisted of a baseline period, a 6-min passive (International Affective Picture System: IAPS) and an 8-min active stress task (Paced Auditory Serial Addition Test: PASAT) with 45-min rest post-tasks. Heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured throughout the testing protocol. Blood samples were collected after each time point to measure circulating and lipopolysaccharide (LPS)-stimulated interleukin-6 (IL-6), systemic inflammation response index (SIRI) and the neutrophil:lymphocyte ratio (NLR).

Results: There was a significant positive relationship between changes in HR during the IAPS and habitual SB (B = 1.061; p=.008). There were no relationships between the change in SBP or DBP during the IAPS and habitual SB (all p>.05). There were no relationships between acute psychological stress-induced circulating IL-6, LPS-stimulated IL-6, NLR or SIRI and habitual MVPA or SB levels.

Discussion: This is the first study to investigate passive psychological stress-induced responses in the context of SB and builds on previous work in relation to SB and inflammatory responses to active stress. We found no associations between the inflammatory response to a passive or 3 active psychological stress task and SB or MVPA levels in healthy young adults, but since our participants were very lean (21.7% body fat), findings may differ in other populations