The effects of acute exercise on short- and long-term memory: Considerations for the timing of exercise and phases of memory

Abstract

The specific questions addressed from this research include: (1) Does high-intensity acute exercise improve memory?, (2) If so, do the mechanisms occur via encoding, consolidation, or retrieval? and (3) If acute exercise occurs in multiple phases of memory (e.g., before encoding and during consolidation), does this have an additive effect on memory? Three experimental, within-subject, counterbalanced studies were conducted among young adults. High-intensity exercise involved a 20-minutes bout of exercise at 75% of heart rate reserve. Memory was evaluated from a word-list task, including multiple evaluations out to 24-hours post-encoding. The timing of the exercise and memory assessments were carefully positioned to evaluate whether any improvements in memory were driven by mechanisms related to encoding, consolidation, and/or retrieval. We demonstrated that high-intensity acute exercise enhanced memory. This effect was robust (repeatable) and occurred through encoding, consolidation and retrieval-based mechanisms. Further, incorporating acute exercise into multiple phases of memory additively enhanced memory function.

Acute and Chronic Exercise Effects on Human Memory: What We Know and Where to Go from Here

“…The timing of the bout of exercise relative to the memory task is an important factor influencing the exercise–memory relationship [ 24 ]. Research demonstrates that acute exercise (compared to no exercise) prior to memory encoding can enhance long-term memory [ 15 , 20 , 21 , 23 , 69 , 70 , 71 ], and similarly, long-term memory can be enhanced when exercise occurs post-encoding [ 29 , 56 , 72 ]. Further, some research demonstrates that the memory benefits from exercise occur regardless of whether acute exercise occurs before or after memory encoding [ 29 , 73 ], and one study even suggests that exercise performed both before and after memory encoding results in the largest benefits for long-term memory [ 22 ].…”

“…A potential mechanism through which acute exercise may alter retrieval-related mechanisms is through improvements in iteminvariant retrieval, which involves the executive control to allocate mental resources to search for items in memory. Speculatively, exercise may help to increase such executive control-related monitoring processes to facilitate successful memory retrieval [29]. Illustration of the use of acute and chronic exercise designs to evaluate the effects of exercise on memory and across different phases of memory.…”

“…The long-term memory performance was similar across conditions, suggesting that engaging in exercise during both memory phases was not greater in improving memory than when exercise was performed in a single memory phase. Loprinzi et al [ 29 ] followed this up with a separate experiment but, instead, used a high-intensity bout of acute exercise, ultimately showing that exercising during both phases was better at enhancing long-term memory when compared to exercising during a single memory phase. Similar findings were also demonstrated by Slutsky-Ganesh, Etnier and Labban [ 22 ].…”

“…Despite these studies, additional work is needed in this area. For example, if exercise does additively influence memory when occurring in multiple phases (e.g., before encoding and during consolidation), it is unclear as to the optimal time within each phase that these exercise bouts should occur (e.g., before encoding and early consolidation or before encoding and late consolidation) [ 29 ].…”

Sex Hormone and Sex Hormone Receptors Modulation of Exercise-induced Neurogenesis

“…The detailed mechanism of this exercise-induced neurogenesis, however, has yet to be clear [2,3]. As the database accumulated, ample studies uncover that sex fills in as a sectional mediator on the impacts of activityinduced benefits (e.g., lowered depressive symptoms, enhanced memory, enlarged hippocampal volume), which is indicated by the differentially affected neural and behavioral results [4,5]. Intense studies focused on the mechanism of sex hormones (specifically androgen and estrogen) regulating base-line adult-born neurogenesis.…”