Moderate-to-vigorous intensity cycling exercise immediately after visual learning enhances delayed recognition memory performance.

A single bout of acute aerobic exercise has been shown to improve long-term memory, though it is unclear if exercise before learning or after learning is optimal for memory enhancement. Although some research has demonstrated that exercise before learning is ideal, investigations have consistently shown that acute arousal post-learning is a powerful memory enhancer. Therefore, the purpose of this investigation was to compare the effects of self-perceived hard cycling before or after learning on recognition memory for emotional and neutral images, and examine the relationship between central noradrenergic activity and memory performance. Seventy-two males and females (18-35 years of age) participated in this between-subjects study. Participants were randomly assigned to one of the following groups: exercise before learning, exercise after learning, and control. Participants in the exercise groups engaged in 20 min of cycling at a rating of perceived exertion (RPE) of 15 ("hard") on the Borg RPE scale before or after viewing a series of 90 pleasant, unpleasant, and neutral images (30 each). Participants in the control group engaged in no exercise before or after image viewing. At several time points throughout the experiment, saliva was collected to measure salivary alpha amylase (sAA), a marker of central noradrenergic activity. One-week later, recognition memory was assessed where participants viewed 180 images (90 new) and had to identify which images were previously viewed. Participants in the exercise after learning group had significantly higher recognition memory compared to the control group, but this was not seen with exercise before learning. sAA was not correlated with memory in any group, though it did increase during exercise. These results demonstrate that acute self-perceived hard cycling post-learning, but not pre-learning, improves recognition memory, though this was unrelated to the exercise-induced increase in central noradrenergic activity as measured in saliva.

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.

A Comparison of Methods Used to Determine Percent Body Fat, Minimum Wrestling Weight, and Lowest Allowable Weight Class.

ABSTRACT: Cutrufello, PT, Landram, MJ, Venezia, AC, and Dixon, CB. A comparison of methods used to determine percent body fat, minimum wrestling weight, and lowest allowable weight class. J Strength Cond Res 35(3): 633-637, 2021-The National Collegiate Athletic Association's weight management program allows for the use of skinfold measurements (SF), air displacement plethysmography (ADP), and hydrostatic weighing in the assessment of percent body fat (%BF) and determination of a wrestler's minimum wrestling weight (MWW). Dual energy x-ray absorptiometry (DXA) and ultrasound (US) may offer alternative assessment methods. The purpose of this study was to examine %BF, MWW, and the lowest allowable weight class as determined by SF, ADP, DXA, and US. Thirty-three college-aged men (20.8 ± 1.1 years) participated. Urine specific gravity (Usg) was assessed to ensure proper hydration (1.006 ± 0.006). Percent body fat and MWW were then determined using the 4 assessment methods. Each method was significantly different from one another (p < 0.05) with the exception of ADP compared with SF (17.6 ± 7.1% vs. 17.4 ± 6.3%, p = 1.000) and DXA compared with US (20.5 ± 6.2% vs. 19.2 ± 7.5%, p = 0.124). DXA (68.6 ± 7.1 kg) and US (69.3 ± 6.0 kg) determined the lowest MWW, whereas those determined by SF (70.8 ± 6.8 kg) and ADP (70.9 ± 6.6 kg) were significantly greater (p< 0.05). The SEEs for MWW when compared with SF were 3.2, 3.4, and 2.4 kg for ADP, DXA, and US, respectively. Compared with SF, DXA and US would allow wrestlers to certify at a lower weight class 64 and 33% of the time, respectively. When comparing the approved methods (SF and ADP), approximately 50% of subjects would certify at a different weight class depending on the method used. The use of different methods in assessing %BF offer a wide variability in the determination of MWW.

Acute forced exercise increases Bdnf IV mRNA and reduces exploratory behavior in C57BL/6J mice.

Acute exercise has been shown to improve memory in humans. Potential mechanisms include increased Bdnf expression, noradrenergic activity and modification of glutamate receptors. Because mice are commonly used to study exercise and brain plasticity, it is important to explore how acute exercise impacts behavior in this model. C57BL/6J mice were assigned to three groups: control, moderate-intensity running, and high-intensity running. Control mice were placed on a stationary treadmill for 30 minutes and moderate- and high-intensity mice ran for 30 minutes at 12 and 15-17 m/min, respectively. Mice were sacrificed immediately after running and the hippocampus removed. Total Bdnf, Bdnf exon IV, and glutamate receptor subunits were quantified with quantitative polymerase chain reaction. Total and phosphorylated GluR1 (Ser845 and Ser831) protein was quantified following immunoblotting. Utilizing the same protocol for control and high-intensity running, object location memory was examined in a separate cohort of mice. Anxiety-like behavior was assessed in the open field task (OFT) in a third cohort of mice that were separated into four groups: control-saline, control-DSP-4, acute exercise-saline, and acute exercise-DSP-4. DSP-4 was used to lesion the central noradrenergic system. We observed higher Bdnf IV mRNA in high-intensity runners compared to controls, but no effects of acute exercise on memory. In the OFT, runners traveled less distance and spent more time grooming than controls. DSP-4 did not attenuate the effects of exercise. A single bout of exercise increases Bdnf IV mRNA in an intensity-dependent manner; however, high-intensity running reduces exploratory behavior in C57BL/6J mice.

A single bout of hard RPE-based cycling exercise increases salivary alpha-amylase.

Exercise exerts beneficial effects on cognition, in part by stimulating an arousal response that includes the release of catecholamines. Sympathetic nervous system arousal and activation of the noradrenergic system in particular may enhance cognitive performance. Measurement of salivary alpha-amylase, a non-invasive biomarker of central noradrenergic activity, is a promising avenue for characterizing the arousal-mediated effects of exercise on cognition. However, the effectiveness of high-intensity acute exercise, and the time course of sAA concentrations following exercise, has not been clearly described. The purpose of this study was to determine the effects of 20 min of perceived exertion-based high-intensity cycling exercise on salivary alpha-amylase levels in healthy young adults. We utilized a repeated-measures design to examine the sAA response to cycling exercise, rest, and an emotional picture viewing task. Thirty-two participants between the ages of 18-30 viewed pleasant, neutral, and unpleasant pictures from the International Affective Picture System. Before and after the task, participants completed either 20 min of seated rest or cycling exercise at an intensity corresponding to 15 ("hard") on Borg's Ratings of Perceived Exertion scale. Salivary alpha-amylase was assessed at time points immediately before and after rest, exercise, and the picture viewing task. Exercise elicited a robust increase in salivary alpha-amylase approximately six times higher than that induced by emotional picture viewing. Importantly, the observed exercise-induced increase in salivary alpha-amylase returned to a level comparable to baseline after ten minutes. These findings have meaningful implications for future work characterizing the relationship between exercise and arousal-mediated effects on cognitive performance.

Estrogen-dependent modifications to hippocampal plasticity in paternal California mice (Peromyscus californicus).

In many biparental species, mothers and fathers experience similar modifications to circulating hormones. With these modifications come alterations in neural structure and function suggesting that neuroendocrine mechanisms may underlie postpartum plasticity in both males and females. In the biparental California mouse (Peromyscus californicus), adult neurogenesis is maintained and anxiety-like behavior is attenuated in fathers during the mid-postpartum period. Given a causal relationship between estrogen and regulation of both adult neurogenesis and anxiety, we aimed to elucidate the role of estrogen-dependent mechanisms in paternal experience-related modifications to hippocampal neuroplasticity in California mice. In Experiment 1, hippocampal estrogen receptor beta (ERß) mRNA expression, along with circulating estradiol concentrations, were determined throughout the postpartum period. An upregulation in ERß expression was observed in postnatal day 16 males compared to virgins. Additionally, a rise in circulating estradiol concentrations was detected on postnatal day 2 compared to virgins; levels began to decline toward virgin levels on postnatal day 16 and postnatal day 30. In Experiment 2, we determined the role of estrogen-dependent mechanisms in adult neurogenesis and anxiety-like behavior by treating virgin and paternal males with saline or the selective estrogen receptor modulator, tamoxifen (TMX), during the time of axon extension (i.e., one week after bromodeoxyuridine injection). While TMX failed to alter elevated plus maze performance, TMX treatment inhibited survival of adult born neurons but only in paternal mice. These findings highlight the potential for estrogen-dependent pathways to mediate hippocampal adult neurogenesis in paternal mice.

Recent Research in the Genetics of Exercise Training Adaptation.

In the present review, we focus on evaluating the state of the literature in the area of genetic aspects of exercise training adaptation, in particular focusing on findings published since 2009. Our focus is primarily on studies examining genetic polymorphisms and their association with variability in training responses for a number of exercise-related traits, including aerobic fitness, hemodynamic variables, metabolic traits, body composition and obesity, and muscular strength and size. Very few large-scale studies are available to provide the quality scientific evidence needed to conclusively identify specific genetic factors that contribute to exercise training adaptations. As such, despite years of effort by a number of groups, the search continues for specific genes and combinations of genetic factors that contribute to the interindividual variability observed in phenotype adaptations to exercise training interventions.

Sex-dependent and independent effects of long-term voluntary wheel running on Bdnf mRNA and protein expression.

UNLABELLED: The beneficial effects of physical activity on brain health (synaptogenesis, neurogenesis, enhanced synaptic plasticity, improved learning and memory) appear to be mediated through changes in region-specific expression of neurotrophins, transcription factors, and postsynaptic receptors, though investigations of sex differences in response to long-term voluntary wheel running are limited. PURPOSE: To examine the effect of five months of voluntary wheel running on hippocampal mRNA and protein expression of factors critical for exercise-induced structural and functional plasticity in male and female adult mice. METHODS: At 8weeks of age, male and female C57BL/6 mice were individually housed with (PA; n=20; 10 male) or without (SED; n=20; 10 male) access to a computer monitored voluntary running wheel. At 28weeks, all mice were sacrificed and hippocampi removed. Total RNA was isolated from the hippocampus and expression of total Bdnf, Bdnf transcript IV, tPA, Pgc-1a, GluR1, NR2A, and NR2B were assessed with quantitative RT-PCR and total and mature Bdnf protein were assessed with ELISA. RESULTS: We found significantly higher Bdnf IV mRNA expression in PA males (p=0.03) and females (p=0.03) compared to SED animals. Total Bdnf mRNA expression was significantly greater in PA males compared to SED males (p=0.01), but there was no difference in females. Similarly, we observed significantly higher mature Bdnf protein in PA males compared to SED males (p=0.04), but not in females. CONCLUSION: These findings indicate that the impact of long-term voluntary wheel running on transcriptional and post-translational regulation of Bdnf may be sex-dependent, though the activity-dependent Bdnf IV transcript is sensitive to exercise independent of sex.

Lifelong parental voluntary wheel running increases offspring hippocampal Pgc-1α mRNA expression but not mitochondrial content or Bdnf expression.

When exercise is initiated during pregnancy, offspring of physically active mothers have higher hippocampal expression of brain-derived neurotrophic factor (Bdnf) and other plasticity-associated and mitochondria-associated genes, resulting in hippocampal structural and functional adaptations. In the present study, we examined the effects of lifelong parental voluntary wheel running (before, during, and after pregnancy) on offspring hippocampal mRNA expression of genes implicated in the exercise-induced improvement of cognitive function. C57BL/6 mice were individually housed at 8 weeks of age with (EX, n=20) or without (SED, n=20) access to a computer-monitored voluntary running wheel for 12 weeks before breeding. EX breeders maintained access to the voluntary running wheel throughout breeding, pregnancy, and lactation. Male offspring were housed in sedentary cages, regardless of the parental group, and were killed at 8 (n=18) or 28 weeks (n=19). PCR was used to assess mRNA expression of several genes and mitochondrial content (ratio of mitochondrial to nuclear DNA) in hippocampal homogenates. We found significantly higher peroxisome proliferator-activated receptor γ coactivator 1 α (Pgc-1α) mRNA expression in EX offspring compared with SED offspring at 8 weeks (P=0.04), although the effect was no longer present at 28 weeks. There was no difference in mitochondrial content or expression of Bdnf or any other mRNA target between offspring at 8 and 28 weeks. In contrast to exercise initiated during pregnancy, parental voluntary physical activity initiated early in life and maintained throughout pregnancy has little effect on offspring mRNA expression of genes implicated in exercise-induced hippocampal plasticity.

Sex-specific effects of exercise ancestry on metabolic, morphological and gene expression phenotypes in multiple generations of mouse offspring.

Early life and preconception environmental stimuli can affect adult health-related phenotypes. Exercise training is an environmental stimulus affecting many systems throughout the body and appears to alter offspring phenotypes. The aim of this study was to examine the influence of parental exercise training, or 'exercise ancestry', on morphological and metabolic phenotypes in two generations of mouse offspring. The F0 C57BL/6 mice were exposed to voluntary exercise (EX) or sedentary lifestyle (SED) and bred with like-exposed mates to produce an F1 generation. The F1 mice of both ancestries were sedentary and killed at 8 weeks or bred with littermates to produce an F2 generation, which was also sedentary and killed at 8 weeks. Small but broad generation- and sex-specific effects of exercise ancestry were observed for body mass, fat and muscle mass, serum insulin, glucose tolerance and muscle gene expression. The F1 EX females were lighter than F1 SED females and had lower absolute tibialis anterior and omental fat masses. Serum insulin was higher in F1 EX females compared with F1 SED females. The F2 EX females had impaired glucose tolerance compared with F2 SED females. Analysis of skeletal muscle mRNA levels revealed several generation- and sex-specific differences in mRNA levels for multiple genes, especially those related to metabolic genes (e.g. F1 EX males had lower mRNA levels of Hk2, Ppard, Ppargc1a, Adipoq and Scd1 than F1 SED males). These results provide preliminary evidence that parental exercise training can influence health-related phenotypes in mouse offspring.

Use of creatine in the elderly and evidence for effects on cognitive function in young and old.

The ingestion of the dietary supplement creatine (about 20 g/day for 5 days or about 2 g/day for 30 days) results in increased skeletal muscle creatine and phosphocreatine. Subsequently, the performance of high-intensity exercise tasks, which rely heavily on the creatine-phosphocreatine energy system, is enhanced. The well documented benefits of creatine supplementation in young adults, including increased lean body mass, increased strength, and enhanced fatigue resistance are particularly important to older adults. With aging and reduced physical activity, there are decreases in muscle creatine, muscle mass, bone density, and strength. However, there is evidence that creatine ingestion may reverse these changes, and subsequently improve activities of daily living. Several groups have demonstrated that in older adults, short-term high-dose creatine supplementation, independent of exercise training, increases body mass, enhances fatigue resistance, increases muscle strength, and improves the performance of activities of daily living. Similarly, in older adults, concurrent creatine supplementation and resistance training increase lean body mass, enhance fatigue resistance, increase muscle strength, and improve performance of activities of daily living to a greater extent than resistance training alone. Additionally, creatine supplementation plus resistance training results in a greater increase in bone mineral density than resistance training alone. Higher brain creatine is associated with improved neuropsychological performance, and recently, creatine supplementation has been shown to increase brain creatine and phosphocreatine. Subsequent studies have demonstrated that cognitive processing, that is either experimentally (following sleep deprivation) or naturally (due to aging) impaired, can be improved with creatine supplementation. Creatine is an inexpensive and safe dietary supplement that has both peripheral and central effects. The benefits afforded to older adults through creatine ingestion are substantial, can improve quality of life, and ultimately may reduce the disease burden associated with sarcopenia and cognitive dysfunction.