Brief exercise enhances intrusive memories of traumatic stimuli.

Brief physical exercise enhances memories for neutral events, and recently has been shown to modulate fear learning in animals. To date there is no evidence pertaining to the impact of exercise on emotional memories in humans. Accordingly, this study investigated the role of brief exercise in the development of emotional intrusive memories. Forty-nine university students (18-29year olds) viewed a car accident film depicting accident and injury, and were then randomly assigned to engage in either 10min of intense exercise or easy walking. Two days following the experiment participants were assessed for both intrusive memories of the film and intentional recall of film details. Results indicated that participants in the exercise relative to the walking condition reported more intrusive memories, but not voluntarily recalled memories, of the car accident film two days later. These findings are consistent with recent evidence of exercise-induced emotional learning in animals, and point to the potential for physical activity to contribute to the development of intrusions in the context of encoding emotionally-laden information.