scholarly journals Effects of acute exercise on directed forgetting

2020 ◽  
Vol 10 (4) ◽  
pp. 418-421
Author(s):  
Paul D. Loprinzi ◽  
Jacob Harper ◽  
Tatjana Olinyk ◽  
Jessica Richards
Keyword(s):  
High Intensity ◽  
Present Experiment ◽  
Acute Exercise ◽  
Directed Forgetting ◽  
Context Change ◽  
Mental Context ◽  
Inhibitory Mechanisms ◽  
Change Mechanisms ◽  
L1 And L2 ◽  
Cost Effect

Background: The directed forgetting paradigm involves individuals encoding a list of words(List 1; L1) and then, prior to encoding a second list of words (List 2; L2), they are given specific instructions to either remember all the words from L1 or to try and forget these words. In this paradigm, after encoding L1, those who are given the directed forgetting (DF) instructions tend tore call more words for L2 when compared to those who were given the remember (R) instructions(DF benefit effect). Similarly, those given the DF instructions tend to recall fewer words from L1(DF cost effect). This DF phenomenon may, in part, occur via attentional inhibitory mechanisms, or mental context-change mechanisms, which may be influenced via acute exercise. Methods: The present experiment investigates if acute exercise can facilitate DF when exercise occurs after L1 forgetting instructions. Participants (N = 97; Mage = 21 years) were randomly assigned into either acute exercise (15-min high-intensity aerobic exercise) plus DF (EX + DF),2) DF (directed forgetting) only (DF) or 3) R (remember) only (R). A standard two list (L1 and L2)DF paradigm was employed. Results: We observed evidence of a DF cost effect, but not a DF benefit effect. For L1, although both EX + DF and DF differed from R, there was no difference between EX + DF and DF. Further, although for L2, EX + DF was different than DF, neither of these groups differed when compared to R. Conclusion: We reserve caution in suggesting that exercise had a DF effect.

scholarly journals High-Intensity Acute Exercise and Directed Forgetting on Memory Function

Medicina ◽  
2019 ◽  
Vol 55 (8) ◽  
pp. 446
Author(s):  
Mary Elizabeth Pace ◽  
Paul D. Loprinzi
Keyword(s):  
High Intensity ◽  
Acute Exercise ◽  
Memory Performance ◽  
Memory Function ◽  
Word List ◽  
Directed Forgetting ◽  
Inhibition Mechanism ◽  
Acute Bout ◽  
Parallel Group ◽  
Main Effect

Background and Objectives: Despite accumulating research demonstrating that acute exercise may enhance memory function, very little research has evaluated whether acute exercise can effectuate intentional directed forgetting (DF), an adaptative strategy to facilitate subsequent memory performance. Materials and Methods: A three-arm parallel-group randomized controlled intervention was employed. Participants were randomized into one of three groups, including: (1) exercise plus DF (Ex + DF), (2) DF (directed forgetting) only (DF) and (3) R (remember) only (R). The acute bout of exercise included 15 min of high-intensity treadmill exercise. The memory assessment involved the presentation of two-word lists. After encoding the first word list, participants were either instructed to forget all of those words (DF) or to remember them. Following this, participants encoded the second word list. Results: We observed a statistically significant main effect for list F(1, 57) = 12.27, p < 0.001, η2p = 0.18, but no main effect for group F(2, 57) = 1.32, p = 0.27, η2p = 0.04, or list by group interaction, F(2, 57) = 2.89, p = 0.06, η2p = 0.09. Conclusion: This study demonstrates a directed forgetting effect in that cueing an individual to forget a previously encoded list of items facilitates memory performance on a subsequent list of items. However, we failed to demonstrate any beneficial effect of acute exercise in facilitating directed forgetting. These findings are discussed in the context of directed forgetting theories, particularly the attention inhibition mechanism, as well as the timing of the acute bout of exercise.

Acute high-intensity aerobic exercise increases gene expression of calcium-related proteins and activates endoplasmic reticulum stress responses in diabetic hearts

2020 ◽  
pp. 1-14
Author(s):  
H.O. Ness ◽  
K. Ljones ◽  
M. Pinho ◽  
M.A. Høydal
Keyword(s):  
Gene Expression ◽  
Exercise Training ◽  
Er Stress ◽  
Aerobic Exercise ◽  
Stress Responses ◽  
Mitochondrial Respiration ◽  
High Intensity ◽  
Acute Exercise ◽  
Contractile Function ◽  
Aerobic Exercise Training

Regular aerobic exercise training has a wide range of beneficial cardiac effects, but recent data also show that acute very strenuous aerobic exercise may impose a transient cardiac exhaustion. The aim of this study was to assess the response to acute high-intensity aerobic exercise on properties of mitochondrial respiration, cardiomyocyte contractile function, Ca2+ handling and transcriptional changes for key proteins facilitating Ca2+ handling and endoplasmic reticulum (ER) stress responses in type 2 diabetic mice. Diabetic mice were assigned to either sedentary control or an acute bout of exercise, consisting of a 10×4 minutes high-intensity interval treadmill run. Mitochondrial respiration, contractile and Ca2+ handling properties of cardiomyocytes were analysed 1 hour after completion of exercise. Gene expression levels of key Ca2+ handling and ER stress response proteins were measured in cardiac tissue samples harvested 1 hour and 24 hours after exercise. We found no significant changes in mitochondrial respiration, cardiomyocyte contractile function or Ca2+ handling 1 hour after the acute exercise. However, gene expression of Atp2a2, Slc8a1 and Ryr2, encoding proteins involved in cardiomyocyte Ca2+ handling, were all significantly upregulated 24 hours after the acute exercise bout. Acute exercise also altered gene expression of several key proteins in ER stress response and unfolded protein response, including Grp94, total Xbp1, Gadd34, and Atf6. The present results show that despite no significant alterations in functional properties of cardiomyocyte function, Ca2+ handling or mitochondrial respiration following one bout of high intensity aerobic exercise training, the expression of genes involved in Ca2+ handling and key components in ER stress and the unfolded protein response were changed. These transcriptional changes may constitute important steps in initiating adaptive remodelling to exercise training in type 2 diabetes.

scholarly journals A Short Bout of High-intensity Exercise Alters Ipsilesional Motor Cortical Excitability Post-stroke

2019 ◽  
Author(s):  
Xin Li ◽  
Charalambos C. Charalambous ◽  
Darcy S. Reisman ◽  
Susanne M. Morton
Keyword(s):  
High Intensity ◽  
Acute Exercise ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
High Intensity Exercise ◽  
Exercise Protocol ◽  
Post Stroke ◽  
Motor Cortical Excitability ◽  
Motor Cortical ◽  
Lactate Levels

AbstractBackgroundAcute exercise can increase motor cortical excitability and enhance motor learning in healthy individuals, an effect known as exercise priming. Whether it has the same effects in people with stroke is unclear.ObjectivesThe objective of this study was to investigate whether a short, clinically-feasible high-intensity exercise protocol can increase motor cortical excitability in non-exercised muscles of chronic stroke survivors.MethodsThirteen participants with chronic, unilateral stroke participated in two sessions, at least one week apart, in a crossover design. In each session, they underwent either high-intensity lower extremity exercise or quiet rest. Motor cortical excitability of the extensor carpi radialis muscles was measured bilaterally with transcranial magnetic stimulation before and immediately after either exercise or rest. Motor cortical excitability changes (post-exercise or rest measures normalized to pre-test measures) were compared between exercise vs. rest conditions.ResultsAll participants were able to reach the target high-intensity exercise level. Blood lactate levels increased significantly after exercise (p < 0.001, d = 2.85). Resting motor evoked potentials from the lesioned hemisphere increased after exercise compared to the rest condition (p = 0.046, d = 2.76), but this was not the case for the non-lesioned hemisphere (p = 0.406, d = 0.25).ConclusionsHigh-intensity exercise can increase lesioned hemisphere motor cortical excitability in a non-exercised muscle post-stroke. Our short and clinically-feasible exercise protocol shows promise as a potential priming method in stroke rehabilitation.

Effects of defoliation intensity at the first grazing of forage rape (Brassica napus L.) by dairy cattle on subsequent regrowth potential, total DM consumed, nutritive characteristics and nutrient selection

2013 ◽  
Vol 53 (3) ◽  
pp. 226 ◽  
Author(s):  
G. N. Ward ◽  
J. L. Jacobs
Keyword(s):  
Brassica Napus ◽  
High Intensity ◽  
Present Experiment ◽  
Moisture Stress ◽  
Crop Growth ◽  
Water Soluble ◽  
Axillary Buds ◽  
Forage Crops ◽  
Brassica Napus L ◽  
Growing Period

The use of summer brassica forage crops in dryland dairy systems in southern Victoria is considered a key component of the feed base as they provide home-grown forage with high nutritive characteristics during a period where perennial ryegrass growth is limited due to high summer temperatures and low soil water content. Current knowledge on the use of single-grazing brassica crops such as turnips (Brassica rapa L.) is well defined; however, information on the management of regrowth brassica species that can provide multiple grazings is more limited. The present experiment determined the effect of different grazing regimes (high, medium and low defoliation intensity) at the first grazing on subsequent regrowth capability and nutritive characteristics of Winfred (Brassica napus L.) over the summer growing period across 2 years. We hypothesised that intensive defoliation of a summer regrowth brassica at the first grazing will result in lower total DM yields and harvested estimated metabolisable energy (ME) and crude protein per hectare for the growing season than do more lax grazing options that results in less DM removal at the first grazing. Total DM and estimated ME consumed over the growing period varied between years. In Year 1, more (P < 0.05) DM was consumed at the first grazing and less (P < 0.05) at the subsequent grazing for the high-intensity treatment. However, both total DM and estimated ME consumed were higher (P < 0.05) for the high-intensity treatment than for the low-intensity treatment, while in Year 2, there were no differences between the treatments. Nutritive characteristics and mineral concentrations were relatively unaffected by grazing regimes. The results of the present experiment indicated that the optimum grazing management to maximise total DM yields and consumption of spring-sown Winfred will vary depending on the seasonal growing conditions. In years where moisture stress will be limiting crop growth, a high defoliation-intensity first grazing that consumes a high proportion of DM on offer, including some of the main stem, will maximise the total DM grown and consumed from the crop. Care, however, should be taken not to remove all axillary buds from the remaining stems. In summers where moisture stress is not likely to seriously restrict crop growth, a medium defoliation-intensity grazing where the leaf and petiole, but little of the stem, are removed will maximise DM regrowth, leading to maximum total DM grown for the season. A high defoliation-intensity first grazing that removes at least half the stem is, under these conditions, likely to remove too many axillary buds and reduce water-soluble carbohydrate reserves required for DM regrowth, while a lax first grazing will result in a lower DM regrowth.

Acute Exercise Modulates Feature-selective Responses in Human Cortex

2017 ◽  
Vol 29 (4) ◽  
pp. 605-618 ◽  
Author(s):  
Tom Bullock ◽  
James C. Elliott ◽  
John T. Serences ◽  
Barry Giesbrecht
Keyword(s):  
High Intensity ◽  
Acute Exercise ◽  
Tuning Curve ◽  
Brain Activity ◽  
Human Vision ◽  
Sensory Cortex ◽  
Orientation Discrimination ◽  
Active Movement ◽  
Low Intensity ◽  
Low Intensity Exercise

An organism's current behavioral state influences ongoing brain activity. Nonhuman mammalian and invertebrate brains exhibit large increases in the gain of feature-selective neural responses in sensory cortex during locomotion, suggesting that the visual system becomes more sensitive when actively exploring the environment. This raises the possibility that human vision is also more sensitive during active movement. To investigate this possibility, we used an inverted encoding model technique to estimate feature-selective neural response profiles from EEG data acquired from participants performing an orientation discrimination task. Participants (n = 18) fixated at the center of a flickering (15 Hz) circular grating presented at one of nine different orientations and monitored for a brief shift in orientation that occurred on every trial. Participants completed the task while seated on a stationary exercise bike at rest and during low- and high-intensity cycling. We found evidence for inverted-U effects; such that the peak of the reconstructed feature-selective tuning profiles was highest during low-intensity exercise compared with those estimated during rest and high-intensity exercise. When modeled, these effects were driven by changes in the gain of the tuning curve and in the profile bandwidth during low-intensity exercise relative to rest. Thus, despite profound differences in visual pathways across species, these data show that sensitivity in human visual cortex is also enhanced during locomotive behavior. Our results reveal the nature of exercise-induced gain on feature-selective coding in human sensory cortex and provide valuable evidence linking the neural mechanisms of behavior state across species.

scholarly journals The effects of acute exercise on short- and long-term memory: Considerations for the timing of exercise and phases of memory

2021 ◽  
Vol 17 (1) ◽  
pp. 85-103
Author(s):  
Paul D. Loprinzi ◽  
Sierra Day ◽  
Rebecca Hendry ◽  
Sara Hoffman ◽  
Alexis Love ◽  
...  
Keyword(s):  
Heart Rate ◽  
High Intensity ◽  
Acute Exercise ◽  
Memory Function ◽  
Word List ◽  
Long Term Memory ◽  
Heart Rate Reserve ◽  
Term Memory ◽  
Short And Long Term

The specific questions addressed from this research include: (1) Does high-intensity acute exercise improve memory?, (2) If so, do the mechanisms occur via encoding, consolidation, or retrieval? and (3) If acute exercise occurs in multiple phases of memory (e.g., before encoding and during consolidation), does this have an additive effect on memory? Three experimental, within-subject, counterbalanced studies were conducted among young adults. High-intensity exercise involved a 20-minutes bout of exercise at 75% of heart rate reserve. Memory was evaluated from a word-list task, including multiple evaluations out to 24-hours post-encoding. The timing of the exercise and memory assessments were carefully positioned to evaluate whether any improvements in memory were driven by mechanisms related to encoding, consolidation, and/or retrieval. We demonstrated that high-intensity acute exercise enhanced memory. This effect was robust (repeatable) and occurred through encoding, consolidation and retrieval-based mechanisms. Further, incorporating acute exercise into multiple phases of memory additively enhanced memory function.

High-intensity interval exercise in the cold regulates acute and postprandial metabolism

2020 ◽  
Author(s):  
Stephanie Munten ◽  
Lucie Ménard ◽  
Jeffrey Gagnon ◽  
Sandra C. Dorman ◽  
Ania Mezouari ◽  
...  
Keyword(s):  
Lipid Oxidation ◽  
High Intensity ◽  
Acute Exercise ◽  
Moderate Intensity ◽  
Postprandial Metabolism ◽  
Interval Exercise ◽  
Cold Environments ◽  
Postprandial Lipid Metabolism ◽  
Postprandial Lipid ◽  
High Intensity Interval

High-Intensity Interval Exercise (HIIE) has been shown to be more effective than moderate-intensity exercise for increasing acute lipid oxidation and lowering blood lipids during exercise and postprandially. Exercise in cold environments is also known to enhance lipid oxidation, however the immediate and long-term effects of HIIE exercise in cold are unknown. The purpose of this study was to examine the effects cold stress during HIIE on acute exercise metabolism and postprandial metabolism. Eleven recreationally active individuals (age: 23±3 years, weight: 80±9.7 kg, V̇O2peak: 39.2±5.73 mL·kg-1·min-1) performed evening HIIE sessions (10x60s cycling, 90% V̇O2peak interspersed with 90s active recovery, 30% V̇O2peak) in thermoneutral (HIIE-TN, control; 21°C) and cold environments (HIIE-CO; 0°C), following a balanced crossover design. The following morning, participants consumed a high-fat meal. Indirect calorimetry was used to assess substrate oxidation, and venous blood samples were obtained to assess changes in noncellular metabolites. During acute exercise, lipid oxidation was 113% higher in HIIE-CO (p=0.002) without differences in V̇O2 and EE (p≥0.162) between conditions. Postprandial V̇O2, lipid and CHO oxidation, plasma insulin and triglyceride concentrations were not different between conditions (p>0.05). Postprandial blood LDL-C levels were higher in HIIE-CO two hours after the meal (p=0.003). Postprandial glucose AUC was 49% higher in HIIE-CO vs HIIE-TN (p=0.034). Under matched energy expenditure conditions, HIIE demonstrated higher lipid oxidation rates during exercise in the cold; but only marginally influenced postprandial lipid metabolism the following morning. In conclusion, HIIE in the cold seemed to be less favorable for postprandial lipid and glycemic responses.

Effects of Exercise on Explicit Memory Function: Incidental and Intentional Encoding May Depend on Exercise Timing

2020 ◽  
pp. 003151252097967
Author(s):  
Paul D. Loprinzi ◽  
Ashley Lovorn ◽  
Jackson Gilmore
Keyword(s):  
High Intensity ◽  
Explicit Memory ◽  
Acute Exercise ◽  
Vigorous Physical Activity ◽  
Memory Function ◽  
Recognition Task ◽  
High Intensity Exercise ◽  
Exercise Behavior ◽  
Control Group ◽  
Exercise Timing

The present experiment evaluated the effects of self-reported exercise behavior and an acute bout of high-intensity exercise on explicit memory function. The memory tasks were encoded either incidentally or intentionally; for intentional encoding, participants were told to focus on memorizing the stimuli (words), whereas for incidental encoding, participants were unaware that they would be subsequently asked to complete an object recognition task. Among a sample of 150 adults (Mage = 20 years), randomly assigned experimental participants engaged in the following task sequence: (a) incidentally encoded a series of objects, (b) engaged in 20 minutes of high-intensity exercise, (c) intentionally encoded a word list, and (d) completed explicit memory retrieval tasks. Control group participants viewed a time matched video in lieu of high intensity exercise. We measured self-reported exercise behavior via an exercise questionnaire. We did not observe convincing evidence of an effect of high-intensity acute exercise, when occurring during the early consolidation period, on memory function, for either incidental or intentional encoding tasks. However, self-reported engagement in moderate-to-vigorous physical activity was favorably associated with explicit memory performance.

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