Fig 1. Study procedure.

Each participant completed two sessions spaced two weeks apart. In each session, participants completed an episodic memory test where they were presented a list of 15 words aurally and asked to freely recall these words on three occasions: (i) immediately following presentation, (ii) after a 30-minute retention interval, and (iii) after 24 hours. Crucially, the 30-minute retention interval between the immediate and 30-minute free recall tests comprised our experimental manipulation. In Session 1, participants experienced 25 minutes of higher intensity exercise (interval running) and, in Session 2, they experienced 25 minutes of lower intensity exercise (walking). Different wordlists were used in Session 1 and Session 2. The study took place in a naturalistic setting in the North East of England, UK.