Abstract
Background: Acute exercise has been shown to influence cognitive performance, particularly memory; however, the impact of exercise timing relative to memory encoding remains unclear. Most studies have examined single temporal conditions in isolation, limiting understanding of how exercise before, during, or after encoding differentially affects memory processes.Objective: This study aimed to investigate the effects of moderate- intensity aerobic exercise and the timing of memory encoding on short-term and long-term memory retention in healthy young adults.Methods: This pilot study employed a randomized controlled mixed factorial design with one between-subject factor (exercise timing condition) and one within-subject factor (memory assessment time point). Participants (N=46, (21.89 ± 2.83 years)) were assigned to one of four conditions: encoding before exercise, during exercise, after exercise, or a non-exercise control. The intervention consisted of a 25-minute moderate-intensity cycling protocol (60–70% HRmax). Memory performance was assessed using standardized word recall tasks at baseline, immediately post-encoding, and after a 24-hour delay. Non-parametric analyses (Kruskal–Wallis and Mann–Whitney U tests) were used to evaluate group differences.Results: No significant differences were observed between groups for baseline or short-term memory performance (p > 0.05). However, significant differences were identified for long-term memory recall (H(3)=8.29, p=0.041). The control group demonstrated the highest long-term retention, while encoding during and after exercise resulted in significantly lower performance compared to control (p=0.043 and p=0.010, respectively). Encoding prior to exercise showed relatively preserved memory performance. Age and education level were significantly associated with memory outcomes, whereas gender was not.Conclusion: The timing of exercise relative to memory encoding may influence long-term memory retention. Moderate-intensity exercise did not consistently enhance memory performance and may be associated with reduced retention when performed during or immediately after encoding. These findings suggest temporal specificity may play an important role in the exercise–cognition relationship.