Muscle tension induced after learning enhances long-term narrative and visual memory in healthy older adults

Arousing events are better remembered than mundane events. Indeed, manipulation of arousal, such as by muscle tension, can influence memory even when it occurs shortly after learning. Indeed, our founding study showed this approach can raise delayed memory performance in older adults to a level comparable to that of unaided young adults. Yet, systematic studies, especially those investigating different modalities or types of memory, have not been done. This study investigated the effects of a brief bout of isometric exercise via handgrip on narrative and visuospatial episodic memory in healthy elders. Forty-seven participants completed the Logical Memory subtest of the Wechsler Memory Scales III (LM) and the Benton Visual Retention Test (BVRT), followed alternately by no treatment and by moderately squeezing a sand-filled latex ball for 1-min (counterbalanced order and test forms). Isometric exercise significantly increased both positive and negative affect ratings. Retention was tested 2 weeks later. Delayed recall and recognition of LM was enhanced by arousal relative to control, as was recognition of the BVRT. The results extend past findings that muscle tension induced after learning modulates memory consolidation, extending findings in elders to suggest that a simple form of isometric exercise can have practical effects, such as aiding memory for stories and images.