Effects of acute exercise on emotional memory

Abstract

Research has demonstrated beneficial effects of acute exercise on memory for neutral materials, such as word lists of neutral valence/low arousal. However, the impacts of exercise on emotional memory is less understood. Across three laboratory experiments in college students, we tested if acute exercise could enhance both neutral and emotional memory performance, anticipating a greater effect for emotional memory. We examined effects of exercise at varying intensities (Experiment 1: high-intensity; Experiment 2: low- and high-intensity; Experiment 3: moderate-intensity), of diverse modalities (Experiment 1: treadmill jogging; Experiment 2: cycling; Experiment 3: open-skill (racquetball) and closed-skill (treadmill jogging) exercise), and on emotional memory performance assessed at increasing levels of hippocampal dependency (Experiment 1: Y/N recognition task; Experiment 2: paired-associative recognition task; Experiment 3: cued-recall task). We found that, in all experiments, acute exercise did not significantly influence emotional or neutral memory performance relative to sedentary control conditions. However, we observed several noteworthy outcomes indicating that acute exercise may be linked to improvements in memory confidence and accuracy for central aspects of emotional memory stimuli, and that select exercise modalities (e.g. treadmill exercise) may also be associated with increased frequency of memory intrusions.

Keywords: Emotional arousal; encoding; episodic; physical activity; valence.

Supplementary Figure 1. Proportion of Remember, Know and New Responses Across Item Type and Time

Note. Item type = old, new; time period = 1- and 7-day follow-up periods. Error bars represent 95% confidence intervals.

Supplementary Figure 2. Proportion of Remember, Know and New Responses

Note. Responses are displayed across item type (old, new) and classification. Error bars represent 95% confidence intervals.

Figure 1. Heart Rate Responses in Experiment 1

Note. HR was measured at rest, midpoint, and at the end of the intervention across the three experimental groups. Error bars represent 95% CI. EPE, Exercise Prior to Encoding; EDC, Exercise During Consolidation; and CON, Control.

Figure 2. Valence and Arousal Ratings of the Studied Images

Note. Error bars represent 95% confidence intervals. EPE, Exercise Prior to Encoding; EDC, Exercise During Consolidation; and CON, Control. For both valence and arousal, numeric values ranged from 1 (low) to 9 (high).

Figure 3. Heart Rate Responses in Experiment 2

Note. HR was measured at rest, 5-minute warm-up, 10-minute midpoint interval, and in the final 10 minutes across the low- and high-intensity experimental groups. Error bars represent 95% CI.

Figure 4. Associative Recognition Accuracy

Note. A) proportion of recognition hits, B) d’-prime. Error bars are 95% confidence intervals around the mean.

Figure 4. Associative Recognition Accuracy

Note. A) proportion of recognition hits, B) d’-prime. Error bars are 95% confidence intervals around the mean.

Figure 5. HR Responses for Each Group Across Time

Note. Error bars (minimally present) represent 95% confidence intervals.

Figure 6. Valence and Arousal Scores Pre- and Post-Emotional Video

Note. Error bars represent 95% confidence intervals. For valence, the response scale ranged from −5 (very bad) to +5 (very good). For arousal, the response scale ranged from 1 (low arousal) to 6 (high arousal).

Figure 7. Impact of Event Survey (Memory Intrusions) Results

Note. Point estimates (y-axis) represent the mean value, with response options ranging from 0 (not at all) to 4 (extremely). Error bars represent 95% confidence intervals.

Figure 8. Emotional Memory Accuracy Results

Note. Emotional memory accuracy results. Estimates (y-axis) are proportions, with error bars representing 95% confidence intervals.

Figure 9. Emotional Memory Confidence Results

Note. Point estimates (y-axis) represent the mean value, with response options ranging from 1 (not at all confident) to 5 (extremely confident). Error bars represent 95% confidence intervals.

Figure 10. Relationship Between Memory Confidence and Accuracy of Peripheral and Central Events

Note. peripheral items (a) and central items (b). Ordinate (y-axis) represents memory accuracy (proportion) and abscissa (x-axis) represents confidence scores. Dashed lines represent 95% confidence interval. For memory confidence, response options ranged from 1 (not at all confident) to 5 (extremely confident).