Acute Physical Exercise in Humans Enhances Reconsolidation of Emotional Memories

Acute Physical Exercise in Humans Enhances Reconsolidation of Emotional Memories. Dharani Keyan and Richard Bryant. Psychoneuroendocrinology, Volume 86, December 2017, Pages 144-151. https://doi.org/10.1016/j.psyneuen.2017.09.019

Highlights
•    Memory reconsolidation occurs during modification after activation of memory.
•    Acute bouts of exercise proximal to learning enhances subsequent memory.
•    Acute exercise after trauma memory reactivation strengthened trauma memory.
•    Exercise during trauma memory reactivation may prolong trauma memories.

Abstract: Increasing evidence suggests that when a memory is reactivated through retrieval, it becomes temporarily vulnerable to environmental or pharmacological manipulation, which can consequently update or strengthen the memory. Physical exercise has been shown to modulate the maintenance of fear memories in animals following memory reactivation. This study investigated the effect of intense exercise in modulating the reconsolidation of trauma memories. Fifty-four undergraduate students watched a trauma film depicting the aftermath of a highway car crash. Two days later, participants engaged in either (a) 20-25 minutes of incremental cycling following a memory reactivation induction (Reactivation/Exercise), (b) 20-25 minutes of mild cycling (Reactivation/No Exercise) following memory reactivation, or (c) 20-25 minutes of incremental cycling but no memory reactivation (No Reactivation/Exercise). Saliva samples were collected to index salivary amylase and cortisol at baseline and post activity. Participants completed memory questionnaires relating to declarative and intrusive memory recall two days after memory reactivation. Reactivation/Exercise participants recalled more central details of the trauma film relative to other participants. Increased cortisol predicted better total memory recall in the Reactivation/Exercise, but not in the other conditions. These findings suggest that intense exercise during the period of memory reactivation enhances subsequent trauma memory, and provides human evidence consistent with recent findings of exercise-induced fear reconsolidation in animals.