Experimental Effects of Acute High-Intensity Resistance Exercise on Episodic Memory Function: Consideration for Post-Exercise Recovery Period

Acute Effects of High-Intensity Resistance Exercise on Recognition of Relational Memory, Lactate, and Serum and Plasma Brain-Derived Neurotrophic Factor

ABSTRACT

Baumgartner, NW, Belbis, MD, Kargl, C, Holmes, MJ, Gavin, TP, Hirai, DM, and Kao, S-C. Acute effects of high-intensity resistance exercise on recognition of relational memory, lactate, and serum and plasma brain-derived neurotrophic factor. J Strength Cond Res XX(X): 000-000, 2024-Acute aerobic exercise improves memory, but this phenomenon is understudied in response to resistance exercise (RE) despite evidence that RE-induced increases in lactate and brain-derived neurotrophic factor (BDNF) play mechanistic roles in memory performance. To determine the acute effect of RE on lactate, BDNF, and their associations with object and relational memory, blood lactate, and serum and plasma BDNF were taken from 36 adults (average age 23.64 ± 3.89 years; 18 woman) before and immediately after 42 minutes of high-intensity RE and a rest condition on counterbalanced days. Subjects then immediately studied a series of paired objects and completed object and relational recognition tasks. Results revealed a condition by trial interaction, previously studied objects were remembered less accurately following RE (d = 0.66) but recognition occurred faster (d = 0.28), indicating a speed-accuracy tradeoff following RE. There was no effect of either intervention on relational recognition performance. Lactate (d = 3.68) and serum BDNF (d = 0.74) increased following RE, whereas there was no time-related change in lactate and serum BDNF following rest. However, changes in lactate and BDNF did not predict any measures of object (rs < 0.25, ps > 0.16) or relation recognition (rs < 0.28, ps > 0.13). Collectively, these findings suggest that acute high-intensity RE selectively improves the processing speed of recognizing objects at the cost of less accurate recognition of previously studied objects. Furthermore, changes in object and relational memory performance are unlikely driven by acute increases in lactate or BDNF following high-intensity RE.

Enhanced memory and hippocampal connectivity in humans 2 days after brief resistance exercise

INTRODUCTION

Exercise has significant health benefits and can enhance learning. A single bout of high-intensity resistance training may be sufficient to improve memory. This study aimed to assess memory enhancement by a single bout of high-intensity resistance training and to examine the neural underpinnings using resting-state functional magnetic resonance imaging (MRI).

METHODS

Sixty young adults (34 men and 26 women), divided into the training and control groups, participated. The first session included verbal memory recall tests (cued- and free-recall), resting-state functional MRI (rs-fMRI), and a single-bout high-intensity resistance training for the training group. Two days later, they underwent post-intervention memory tests and rs-fMRI. The study design was 2 groups × 2 sessions for memory tests, and within training group comparisons for rs-fMRI.

RESULTS

Compared to the control group without resistance training, the training group showed higher cued-recall performance 2 days after the brief resistance training (training: +0.27, control: -0.13, interaction: p = .01), and their free-recall scores were associated with enhanced left posterior hippocampal connectivity (r = .64, p < .001).

CONCLUSIONS

These results suggest that brief high-intensity resistance exercise/strength training could enhance memory without repeated exercising. The quick effect of resistance training on memory and hippocampal connectivity could be revealed. A focused and one-shot exercise may be sufficient to enhance memory performance and neural plasticity in a few days.

The Effects of Acute Resistance Exercise on Memory, Processing Speed, and Mood State After a Cognitive Challenge

ABSTRACT

Venezia, AC, Barney, P, Spagnoli, D, Greco-Hiranaka, C, Piepmeier, AT, Smith, JC, and Weiss, LR. The effects of acute resistance exercise on memory, processing speed, and mood state after a cognitive challenge. J Strength Cond Res 37(9): 1738-1745, 2023-Acute moderate-to-vigorous-intensity aerobic exercise has been shown to improve learning and memory, but the effectiveness of acute high-intensity resistance exercise for improving memory is not fully understood. Like acute aerobic exercise, acute resistance exercise increases arousal and circulating catecholamines, mechanisms suggested to mediate the memory-enhancing effects of acute exercise. Furthermore, although acute exercise has been shown to benefit mood state, it is unknown if high-intensity resistance exercise positively influences mood state after a cognitive challenge. In this within-subjects design, subjects (18- to 25-year-old men) completed an approximately 40-minute session of resistance exercise or seated rest. Immediately after, the Automated Neuropsychological Assessment Metrics (ANAM) Code Substitution (CS)-Learning, CS-Immediate Recognition, and CS-Delayed Recognition tasks were completed, followed by the ANAM Mood Scale. There were no significant effects of exercise on recognition memory; however, CS-Learning (attention and processing speed) was better after resistance exercise ( p = 0.03). After the cognitive challenge, restlessness ( p < 0.001), vigor ( p = 0.03), and depression ( p = 0.047) scores were higher after resistance exercise compared with rest; however, after false discovery rate correction, only restlessness remained significantly different between sessions ( q = 0.002), whereas vigor ( q = 0.09) and depression ( q = 0.09) did not. These results suggest that an acute bout of resistance exercise improves attention and processing speed, although it does not improve recognition memory and has mixed effects on mood state in college-aged men.

Implications of Physical Exercise on Episodic Memory and Anxiety: The Role of the Serotonergic System

There is a growing interest in investigating the effects of physical exercise on cognitive performance, particularly episodic memory. Similarly, an increasing number of studies in recent decades have studied the effects of physical activity on mood and anxiety disorders. Moreover, the COVID-19 pandemic has raised awareness of the importance of regular physical activity for both mental and physical health. Nevertheless, the exact mechanisms underlying these effects are not fully understood. Interestingly, recent findings suggest that the serotonergic system may play a key role in mediating the effects of physical exercise on episodic memory and anxiety. In this review, we discuss the impact of physical exercise on both episodic memory and anxiety in human and animal models. In addition, we explore the accumulating evidence that supports a role for the serotonergic system in the effects of physical exercise on episodic memory and anxiety.

The effects of physical activity timing and complexity on episodic memory: A randomized controlled trial

The role of two types of acute physical activity (PA) bouts were assessed on young adults' free-recall and recognition memory in two experiments, which differed in the temporal relation of PA and word encoding. Before or following training on the Rey Auditory Verbal Learning Task, participants performed a simple two-step dance, a complex four-step dance, or remained seated. Hypotheses proposed that PA prior to encoding and complex PA would enhance PA's mnemonic benefits. Memory assessed post-PA, 24 h, and 7 days after training indicated that timing and complexity of PA did not impact free-recall or recognition memory. Findings differ from a previous study showing complex PA benefited motor learning more than simple PA (Tomporowski & Pendleton, 2018). The inconsistency may be due to different working memory processes underlying consolidation and retrieval of procedural or episodic information. Theory-based explanations regarding memory storage and retrieval are proposed to elucidate this selective process.

Increased cortisol levels caused by acute resistance physical exercise impair memory and learning ability

Acute physical exercise works as an activator of the responses of the human organism to stress. This is based on the activation of the hypothalamic-pituitary-adrenal (HPA) axis, affecting physical, physiological and psychological levels. This study aimed to analyse the effects of a single bout of high-intensity resistance exercise on cognitive-behavioural responses: visuo-spatial path learning and memory, as well as physiological responses (salivary cortisol levels). Nineteen healthy male military-trained powerlifting subjects were tested in a within-subject design on two experimental days with an interval of 48 h. The stress and cognitive variables were measured by cortisol levels and Ruff-Light trail-learning test (RULIT) test scores, respectively. The results showed the immediate influence of acute exercise on cortisol, with significantly higher cortisol levels found in subjects after completion of the acute resistance exercise. In addition, this study found a significant deterioration of memory and learning ability after a dose of intense resistance exercise. In conclusion, the study highlights the relative effects of resistance exercise on cortisol and cognitive performance depending on the intensity and type of the exercise, the moment of measurement and the cerebral areas implicated.

Effects of acute aerobic and resistance exercise on episodic memory function

Accumulating research provides suggestive evidence that acute aerobic exercise may, potentially, enhance episodic memory function post-exercise. Limited research has evaluated whether acute resistance exercise may also enhance episodic memory post-exercise. Furthermore, whether these two exercise modalities have a differential effect on post-exercise episodic memory is relatively unknown. To address these research questions, three experimental studies were conducted (N = 104) among young adults (18-25 years). The experiments implemented acute bouts of aerobic or resistance exercise for 15 min. Episodic memory was comprehensively evaluated post-exercise with a list-learning paradigm and a computerised assessment of what-where-when aspects of episodic memory. Various manipulations (e.g., between vs. within-group) of the study design were implemented across the experiments. Across these three experiments, we failed to find consistent evidence of either type of acute exercise affecting episodic memory performance post-exercise.

Does Aerobic and Resistance Exercise Influence Episodic Memory through Unique Mechanisms?

Aerobic and resistance exercise (acute and chronic) independently and collectively induce beneficial responses in the brain that may influence memory function, including an increase in cerebral blood flow, neurogenesis, neuroelectrical alterations, and protein production. However, whether aerobic and resistance exercise improve memory via similar or distinct mechanisms has yet to be fully explained. Here, we review the unique influence of aerobic and resistance exercise on neural modulation, proteins, receptors, and ultimately, episodic memory. Resistance training may optimize neural communication, information processing and memory encoding by affecting the allocation of attentional resources. Moreover, resistance exercise can reduce inflammatory markers associated with neural communication while increasing peripheral and central BDNF (brain-derived neurotrophic factor) production. Aerobic training increases hippocampal levels of BDNF and TrkB (Tropomyosin receptor kinase B), protein kinases and glutamatergic proteins. Likewise, both aerobic and anaerobic exercise can increase CREB (cAMP response element-binding protein) phosphorylation. Thus, we suggest that aerobic and resistance exercise may influence episodic memory via similar and, potentially, distinct mechanisms.