Physical Activity, Negative Affect, and the Reflex Physiology of Emotion

Abstract

Physical activity participation is consistently associated with improved mood in both healthy individuals and those diagnosed with a mood or anxiety disorder. Yet there is little evidence to support that physical activity affects the physiological outputs from brain systems that govern emotion. Because changes in emotion presumably underlie changes in mood, it is important to examine the physiology of emotion in the context of physical activity participation as well as individual differences in negative affect. PURPOSE: To examine the effects of physical activity history in the modulation of emotional reactivity among individuals with low and high negative affect. METHOD: Participants (n = 72) were selected from Introduction to Psychology classes based on their scores for depression, trait anxiety and physical activity history on a pre-screening questionnaire. To verify affective and physical activity status, upon arrival to the laboratory participants completed the Beck Depression Inventory, the Trait Anxiety Inventory, and Blair's (1984) 7-day physical activity history interview. Each participant was then prepared for the electromyographic recording of the corrugator supercilii (facial frowning) and orbicularis oculi (eye blink) muscles, then viewed valence-homogeneous blocks of 36 pleasant, 36 neutral, and 36 unpleasant pictures in a counterbalanced order. Each picture was shown for 6 seconds, all 36 pictures in a block were presented consecutively, and there was a 3-min inter-block interval. Startle eye blink responses were elicited and recorded every 30 seconds after the delivery of a loud (95 dB) brief (50 ms) acoustic stimulus through headphones. RESULTS: Preliminary analyses showed that those who reported high negative did not show the expected increase in facial frowning during the unpleasant pictures; however, this was evident only in those who also reported low levels of physical activity. Furthermore, this lack of unpleasant responsiveness, compared to the normally physically active and low negative affect participants, persisted throughout the pictures to approximately 60 seconds after the unpleasant pictures had ceased. In addition, individuals with low negative affect who also reported normal levels of physical activity responded with less facial frowning during the viewing of neutral pictures compared to those with high negative affect and/or low levels of physical activity. CONCLUSION: These data suggest that individuals with high negative affect may fail to respond appropriately to unpleasant affective stimuli, and that being physically active may promote a healthy emotional response system. Support: NIH F32-MH066601.