Do slumped and upright postures affect stress responses? A randomized trial.

Objective: The hypothesis that muscular states are related to emotions has been supported predominantly by research on facial expressions. However, body posture also may be important to the initiation and modulation of emotions. This experiment aimed to investigate whether an upright seated posture could influence affective and cardiovascular responses to a psychological stress task, relative to a slumped seated posture.

Method: There were 74 participants who were randomly assigned to either a slumped or upright seated posture. Their backs were strapped with physiotherapy tape to hold this posture throughout the study. Participants were told a cover story to reduce expectation effects of posture. Participants completed a reading task, the Trier Social Stress speech task, assessments of mood, self-esteem, and perceived threat. Blood pressure and heart rate were continuously measured.

Results: Upright participants reported higher self-esteem, more arousal, better mood, and lower fear, compared to slumped participants. Linguistic analysis showed slumped participants used more negative emotion words, first-person singular pronouns, affective process words, sadness words, and fewer positive emotion words and total words during the speech. Upright participants had higher pulse pressure during and after the stressor.

Conclusions: Adopting an upright seated posture in the face of stress can maintain self-esteem, reduce negative mood, and increase positive mood compared to a slumped posture. Furthermore, sitting upright increases rate of speech and reduces self-focus. Sitting upright may be a simple behavioral strategy to help build resilience to stress. The research is consistent with embodied cognition theories that muscular and autonomic states influence emotional responding.