Experimental Effects of Acute Exercise on Episodic Memory Function: Considerations for the Timing of Exercise

Abstract

Our previous work employing a between-subject randomized controlled trial design suggests that exercising prior to memory encoding is more advantageous in enhancing retrospective episodic memory function when compared to exercise occurring during or after memory encoding. The present experiment evaluates this potential temporal effect of acute exercise on memory function while employing a within-subject, counterbalanced design. In a counterbalanced order (via Latin squares), 24 participants completed four visits including (1) exercising (moderate-intensity walking) prior to memory encoding, (2) exercising during memory encoding, (3) exercising after memory encoding, and (4) a control visit (no exercise). Retrospective memory function (short term and long term; 24-hour follow-up) was assessed from a multitrial word list. Prospective memory was assessed from a time-based task. Compared to all other visits, short-term memory was greater in the visit that involved exercising prior to memory encoding (F = 3.76; P = .01; η= .79). Similar results occurred for long-term memory, with no significant effects for prospective memory performance. We provide robust evidence demonstrating that acute moderate-intensity exercise prior to memory encoding is optimal in enhancing short-term and long-term memory function when compared to no exercise as well as exercising during and after memory encoding.

Experimental Effects of Exercise on Forgetting

“…Additionally, and similar to other studies [33][34][35][36], participants were excluded if they: Self-reported as a daily smoker [37,38] Self-reported being pregnant [39] Exercised within 5 hours of testing [40] Consumed caffeine within 3 hours of testing [41] Had a concussion or head trauma within the past 30 days [42] Took marijuana or other illegal drugs within the past 30 days [43] Were considered a daily alcohol user (>30 drinks/month for women; >60 drinks/month for men) [44]…”

Acute Exercise on Reversal Learning

“…The present study, written as a brief report, aimed to evaluate whether acute exercise can enhance a cognitive-related reversal learning effect. The motivation for this experimentation came from past work demonstrating that acute exercise can enhance the functional connectivity of neurons [32], improve cognitive flexibility [15][16][17], as well as improve memory function [1][2][3][4][5][6][7], all of which are important for cognitive-related learning. In the present experiment, our main findings were as follows.…”

“…Emerging research demonstrates that acute exercise is associated with enhanced memory performance [1][2][3][4][5][6][7]. Mechanisms of this potential effect are multifold, including, for example, exercise-induced neuronal excitability, transcription factor expression, and growth factor production [8].…”

Effect of Acute Moderate-Intensity Exercise on Autobiographical Episodic Memory and Semantic Memory

“…In alignment with other related experiments [1][2][3][4][5][6], 20 participants were randomized into both groups (N=40). Recruitment occurred via a convenience-based, non-probability sampling approach (classroom announcement and word-of-mouth).…”

“…Of interest to our group is the effects of exercise on memory function, including both episodic memory (recall of past events) and semantic memory (recall of past information not bound to a particular event). Acute exercise has been shown to enhance episodic memory function, particularly the short-term recall of recently encoded information (e.g., word list) [1][2][3][4][5][6]. Mechanisms of such an effect have been detailed elsewhere [7][8][9][10], and include, for example, exercise-induced alterations in neuronal excitability and priming (e.g., via CREB [cAMP response element binding] phosphorylation) neuronal networks for engram trace development.…”