A single bout of resistance exercise can enhance episodic memory performance

Abstract

Acute aerobic exercise can be beneficial to episodic memory. This benefit may occur because exercise produces a similar physiological response as physical stressors. When administered during consolidation, acute stress, both physical and psychological, consistently enhances episodic memory, particularly memory for emotional materials. Here we investigated whether a single bout of resistance exercise performed during consolidation can produce episodic memory benefits 48 h later. We used a one-leg knee extension/flexion task for the resistance exercise. To assess the physiological response to the exercise, we measured salivary alpha amylase (a biomarker of central norepinephrine), heart rate, and blood pressure. To test emotional episodic memory, we used a remember-know recognition memory paradigm with equal numbers of positive, negative, and neutral IAPS images as stimuli. The group that performed the exercise, the active group, had higher overall recognition accuracy than the group that did not exercise, the passive group. We found a robust effect of valence across groups, with better performance on emotional items as compared to neutral items and no difference between positive and negative items. This effect changed based on the physiological response to the exercise. Within the active group, participants with a high physiological response to the exercise were impaired for neutral items as compared to participants with a low physiological response to the exercise. Our results demonstrate that a single bout of resistance exercise performed during consolidation can enhance episodic memory and that the effect of valence on memory depends on the physiological response to the exercise.

Keywords: Arousal; Emotion; Episodic memory; Exercise; Stress.

Figure 1. Procedure

Flow chart of the procedure for both sessions Note: HR = Heart Rate, BP = Blood Pressure, AA = Alpha Amylase

Figure 2. Physiological Data

Shows the change in the physiological measures after exercise converted into z-scores Note: Data were converted to z-scores to show the change scores (after – before exercise) on a single scale. AA = alpha amylase, HR = heart rate, BP = blood pressure.

Figure 3. Explicit Memory Data

a) Item Memory: Shows the Pr for each group for each valence category b) Recollection Estimates: Shows the remember Pr for each group for each category

Figure 4. Item memory accuracy for high and low responders in the active group

Shows the Pr for the high and low responders within the active group for each valence category