Short Periods Of Exercise Research Articles

Ten-Minute Physical Activity Breaks Improve Attention and Executive Functions in Healthcare Workers.

Occupational health is a major problem in modern work environments. Physical activity breaks (PABs), short exercise periods delivered during working hours, incorporating exergames or outdoor activities, have emerged as a novel approach that could be used to improve work efficiency and workplace wellbeing. Therefore, this study aimed to investigate the impact of PABs on attention levels and executive functions in healthcare workers. A total of 27 healthcare workers (M = 14, W = 13; 49.55 ± 12.46 years), after 4 h of work, randomly performed one of three 10 min conditions weekly in a counterbalanced order: No Physical Activity Break (NPAB); Outdoor Physical Activity Break (OPAB); Physical Activity Break with Exergame (PABEx). After the conditions, executive functions and selective attention were assessed by the Stroop Color and Word Test (SCWT), and the Trail Making A,B test (TMT A,B), respectively. Significant differences between OPAB and NPAB as well as between PABEx and NPAB in the TMT-A test χ2(2) = 44.66 (p < 0.001) and TMT-B test χ2(2) = 48.67 (p < 0.001) were found, respectively. TMT-A and SCWT interference/time scores of the PABEx and OPAB conditions were significantly lower than those of NPAB (p < 0.001). In the SCWT interference/error score, no significant difference was found between the PABEx and NPAB (p > 0.05), but the score was statistically lower in the OPAB condition than PABEx (p = 0.001) and PABEx condition compared to OPAB for TMT-A (p = 0.001). Findings showed that the OPAB and PABEx conditions are effective in improving selective attention and executive functions in healthcare workers. Employers can foster a healthier and more productive workforce by promoting a culture of movement and prioritizing employee health, which in turn can enhance patient care outcomes.

Association between the Timing of Pre-Workout Macronutrient Intake and Rated Appetite among Resistance-Trained Adults in Jbeil, Lebanon.

Macronutrients play an important role in appetite regulation. In addition, adequate nutrient and energy intake, which may be altered by exercise-induced appetite fluctuations, is required to ensure important training outcomes. However, findings regarding appetite responses to macronutrient consumption before training and to different resistance training intensities remain inconclusive. This study investigated the association of three types of macronutrient intake before different intensities of resistance training with appetite. A purposive cross-sectional design was used to collect data from 280 resistance-trained individuals (mean age 26.4 ± 5.8 years) representing five gyms located in Jbeil, Lebanon, and who completed an online questionnaire. Data collected included socio-demographics, nutritional strategies followed by each respondent, training characteristics, and appetite rating before, during and after exercise using a validated visual analogue scale (VAS). A short-term suppression of appetite was reported during resistance-training, with no significant difference in exercise intensities (p > 0.05). In addition, low-fiber carbohydrate and protein food/beverage content consumed 30-60 min before training had an advantage in appetite suppression. In summary, these findings suggest that resistance training combined with pre-workout consumption of a whole meal was associated with appetite suppression, at least during the short period of exercise. From the perspective of appetite control and energy balance, the critical factor is the quantity and quality of macronutrient food sources, in addition to the timing surrounding training of nutrients ingested.

Effects on Human Heart and Breathing Rates by Face Mask‐Wearing, During Short Periods of Exercise

Effects on Human Heart and Breathing Rates by Face Mask‐Wearing, During Short Periods of Exercise

Practicalities for Exercise Prescription in Long-COVID-19 Rehabilitation. A Narrative Review

Many COVID-19 survivors worldwide suffer from persistent symptoms, impaired functional capacity and quality of life. Rehabilitation exercise interventions for the long-term physical consequences of coronavirus disease 2019 (COVID-19) are currently being reported. As a result, the clinical practice and research focus on interventions that support recovery from ongoing symptomatology, independently to hospitalization. To date, the outpatient rehabilitation programs offer various exercise modes and training intensities for people recovering from long-term symptomatology of COVID-19. This narrative review summarizes previous studies that used exercise training protocols at the outpatient rehabilitation setting, presents the effectiveness of training on the functional outcomes and provides practical issues of the application of exercise training which overcome possible respiratory and peripheral muscle limiting factors of exercise and functional capacity for patients with Long-COVID-19. To this end we make recommendations on how better to implement exercise training in future studies so as to maximize training effects. Due to lack of randomized trials, more research is needed in the field of the exercise training modalities that are more effective and in parallel more tolerable for patients with persistent post-COVID-19 symptoms. In this context, interval training mode with short exercise periods can prevent high lactate accumulation and allow more intense exercise stimuli to the deconditioned peripheral muscles with minimal cardiac strain and exercise-induced hyperventilation, thus improving exercise capacity in this patients’ population.

P–073 High-intensity interval training modulates the effects of hypertension on inflammatory mediators in testis in adult spontaneously hypertensive rats

Abstract Study question Is the high-intensity interval training (HIIT) able to prevent the increase of the inflammatory proteins in the testis of spontaneously hypertensive rats (SHR)? Summary answer HIIT for 8 weeks inhibits the increase of the tumor necrosis factor alpha (TNFα) and the interleukin 6 (IL6) in the testis of SHR. What is known already Hypertension increases the inflammatory cytokines of the cardiovascular system, causing damage in the microcirculation and in the testes. Hypertension is a cause of low fertility in men and exercises are indicated to decrease blood pressure and improve overall health. HIIT is characterized by short periods of exercise, with an intensity equal to or greater than the anaerobic threshold, separated by recovery periods. HIIT can be indicated for cardiac patients, as this type of training improves the cardiac autonomic nervous system and lipemic control in both hypertensive and normotensive individuals. Study design, size, duration Male Wistar-Kyoto rats without hypertension and SHRs were divided into 3 groups (n = 4): WKY (Wistar-Kyoto); SHR; and SHR-HIIT (SHRs that performed HIIT). The HIIT was realized in treadmill for 5 days/week for 8 weeks. HIIT started with 5 times of 4 minutes of 100% of the maximum exhaust speed, with active rest intervals of 3 minutes at 60%. There was an increase of once every week until reaching 7 times each session. Participants/materials, setting, methods Samples from testicles were used for immunostainig IL6 and TNFα. After the blocking, the sections were subjected to reaction of specific antibodies IL6 (1:50, E–4, sc–28343) and TNFα (1:50, 52B83, sc–257) at 4ºC overnight, and with secondary antibodies m-IgGK (1:200, IgG-HRP, sc–516) at room temperature for 2 hours. Diaminobenzidine (1:50) was used against Harris stained with Hematoxylin and evaluated in the photomicroscope. Data were analyzed by One-Way ANOVA followed by Tukey post test (P &amp;lt; 0.05). Main results and the role of chance The immunostainig of IL6 was higher in SHR (10.23 ± 0.47) than in SHR-HIIT (8.69 ± .44) group (P = 0,0237). From the same perspective, immunoexpression of TNFα was higher in SHR (10.10 ± 0.42) than WKY (8.24 ± 0.24) and SHR-HIIT (7.82 ± 0.39) groups (P = 0.0018). Limitations, reasons for caution As a limitation of the study, we have no measurement of fertility parameters to affirm that the HIIT improve the fertility because of the reduction of inflammatory mediators. Wider implications of the findings: The hypertension drugs have a negative effect on fertility. HIIT can be suggested as a treatment for hypertension as an alternative to medication, since HIIT can inhibit the increase of the inflammatory mediators in testis and its consequences to the reproduction. Financial support by São Paulo Research foundation, FAPESP (2018/22682–0). Trial registration number 2018/22682–0

A single session of moderate intensity exercise influences memory, endocannabinoids and brain derived neurotrophic factor levels in men

Regular physical exercise enhances memory functions, synaptic plasticity in the hippocampus, and brain derived neurotrophic factor (BDNF) levels. Likewise, short periods of exercise, or acute exercise, benefit hippocampal plasticity in rodents, via increased endocannabinoids (especially anandamide, AEA) and BDNF release. Yet, it remains unknown whether acute exercise has similar effects on BDNF and AEA levels in humans, with parallel influences on memory performance. Here we combined blood biomarkers, behavioral, and fMRI measurements to assess the impact of a single session of physical exercise on associative memory and underlying neurophysiological mechanisms in healthy male volunteers. For each participant, memory was tested after three conditions: rest, moderate or high intensity exercise. A long-term memory retest took place 3 months later. At both test and retest, memory performance after moderate intensity exercise was increased compared to rest. Memory after moderate intensity exercise correlated with exercise-induced increases in both AEA and BNDF levels: while AEA was associated with hippocampal activity during memory recall, BDNF enhanced hippocampal memory representations and long-term performance. These findings demonstrate that acute moderate intensity exercise benefits consolidation of hippocampal memory representations, and that endocannabinoids and BNDF signaling may contribute to the synergic modulation of underlying neural plasticity mechanisms.

A Study of Physical Fitness and Enjoyment on Virtual Running for Exergames

Virtual Reality (VR) technology has advanced forward in everyday life where virtual fitness is possible through physically moving around in the real world. Exergame is a video game for exercise aimed at making exercise more fun. VR exergame applies these trends together for virtual fitness with immersive game play. The VR locomotion is traveling in VR, which is commonly used in adventure role-playing games (RPG). Virtual running can be applied as a locomotion technique for VR exergames. The design of virtual running in VR exergames should be considered as an exercise for fitness and also for enjoyment. This paper proposed two motion-based locomotion techniques: ArmSwing and Squat for virtual running, which are considered as aerobic and strength exercise. These two postures were used to study how physical exertion affected players while interacting in the test scene. Usability, motion sickness, and enjoyment were assessed to analyze the differences of each posture. The results showed that motion sickness and enjoyment of ArmSwing and Squat were not different, while usability was different where ArmSwing was rated higher than Squat. The results from the interviews suggest that most players preferred aerobic exercise (ArmSwing) more than strength exercise (Squat) for a long period of exercise. However, for a short period of exercise, players preferred strength exercise more than aerobic exercise. The adventure-based RPG for exercise needs a solution design appropriate for virtual running in VR, and our results can be a guideline for developers in order to handle motion-based locomotion for VR exergames.

Abstract 12640: Energy Drinks Prolong Early Repolarization (J-T Peak ) Phase in a Healthy Population

Introduction: Energy drinks continue to be the fastest growing beverage market with sales expected to reach $60 billion in the next few years, yet have demonstrated adverse cardiovascular effects such as prolongation of the QTc interval on EKG. While QTc prolongation observed with certain drugs has long been used as an indicator of increased risk of torsade de pointes, recent data has identified the early repolarization interval J-T peak (JTp) as a more specific marker for proarrhythmic potential. Drugs that selectively block the human ether-a-go-go related (hERG) potassium ion channel prolong QTc by prolonging both early repolarization (JTp) and late repolarization (T peak -T end [Tpe] interval), and are associated with an increased risk of torsade. In contrast, drugs that additionally block inward late sodium and L-type calcium prolong QTc by prolonging Tpe but not JTp, and have demonstrated reduced risk of torsade. In 2018, the C-Energy-X study demonstrated QTc prolongation in 22 healthy subjects (mean age 28 ± 7yrs) who consumed energy drink while at rest and following short periods of exercise. Our study provides a secondary analysis of this data in terms of its effect on JTp, a potentially more specific marker for torsade risk. Methods: Using H-Scribe software, two evaluators independently measured JTp and RR intervals from C-Energy-X subjects pre- and post-energy drink consumption in the rest and exercise phases. Values were corrected for heart rate using the linear correction formula JTpc=JTp + 0.150(1-RR), where RR is R-to-R interval. Mean JTpc values from each phase were analyzed using a paired sample two-tailed t -test. Results: In the resting phase following energy drink consumption (PCr), there was a statistically significant increase in JTpc intervals for 77% of subjects by a mean of 10.5ms (baseline=234 ± 21.3ms; PCr=245 ± 22.0ms; p =0.015). In the exercise phase following energy drink consumption (PCe), 64% of subjects increased JTpc intervals by a mean of 0.8ms which was not significant (baseline=225 ± 15.7ms; PCe=226 ± 17.9ms; p =0.845). Conclusion: In the resting phase, energy drink consumption was associated with statistically significant prolongation of JTpc, suggesting a theoretical increased risk of torsade de pointes.

Effect of acute physical exercise on motor sequence memory

Acute physical exercise improves memory functions by increasing neural plasticity in the hippocampus. In animals, a single session of physical exercise has been shown to boost anandamide (AEA), an endocannabinoid known to promote hippocampal plasticity. Hippocampal neuronal networks encode episodic memory representations, including the temporal organization of elements, and can thus benefit motor sequence learning. While previous work established that acute physical exercise has positive effects on declarative memory linked to hippocampal plasticity mechanisms, its influence on memory for motor sequences, and especially on neural mechanisms underlying possible effects, has been less investigated. Here we studied the impact of acute physical exercise on motor sequence learning, and its underlying neurophysiological mechanisms in humans, using a cross-over randomized within-subjects design. We measured behavior, fMRI activity, and circulating AEA levels in fifteen healthy participants while they performed a serial reaction time task before and after a short period of exercise (moderate or high intensity) or rest. We show that exercise enhanced motor sequence memory, significantly for high intensity exercise and tending towards significance for moderate intensity exercise. This enhancement correlated with AEA increase, and dovetailed with local increases in caudate nucleus and hippocampus activity. These findings demonstrate that acute physical exercise promotes sequence learning, thus attesting the overarching benefit of exercise to hippocampus-related memory functions.

Lung morphology and surfactant function in cardiogenic pulmonary edema: a narrative review.

The conventional analysis of acute cardiogenic pulmonary edema involves the development of high pulmonary capillary pressures resulting in hydrostatic gradients for fluid flux out of capillaries into the interstitial space and alveolar spaces. However, some patients respond poorly to diuretic management. The PubMed database was searched to identify experimental studies on pulmonary edema in animals, experimental studies on surfactant function, including patients with pulmonary edema, and clinical studies reporting barrier dysfunction and/or injury in patients with acute pulmonary edema. Studies with animal models demonstrate that high capillary pressures can cause barrier disruption in alveolar capillary units which increases permeability and the transfer of fluid and protein into lung parenchyma. Fluid in alveolar spaces alters surfactant function which increases fluid flux out of capillaries into the lung parenchyma secondary to larger transcapillary hydrostatic gradients. Patients with acute cardiogenic pulmonary edema have increased levels of surfactant protein B in their plasma which reflect barrier disruption and increased levels of tumor necrosis factor alpha which reflect acute tissue injury. Increased surfactant protein B plasma levels are associated with abnormal gas exchange in patients with chronic heart failure. Patients with exercise-induced left ventricular dysfunction have increased levels of surfactant protein B after short periods of exercise. Pathology studies in patients with chronic heart failure have found increased connective tissue in alveolar capillary units and increased numbers of type II alveolar cells, and these changes represent an adaptive response in these patients. Clinicians need to consider the possibility of barrier dysfunction and disruption in patients with both acute and chronic pulmonary edema and understand that diuresis may have a limited effect on symptoms in some patients.

Exercise-induced bronchoconstriction and therapeutic modulation in Iraqi girls intermediate school students

EIB (Exercise-Induced Bronchoconstriction) describes the narrowing that occurs in the airway follow a short period of exercise. EIB is found in 8-10% of normal children population as occult bronchospasm during or after physical activities. The mechanismsofEIB are related to rapid ventilation and mouth breathing which cause heat and water loss during breathing leading to bronchoconstriction. Peak Expiratory Flow Rate (PEFR) measured pre and post-exercise in students aged 12-16 years in girl intermediate school. Any female shows PEFR values reduction 15% after 6 minutes continuous free running considered as asthmatic patient, this give an incidence rate of asthmatic patient of 9% in female students in this age. Treatment of EIB, Zafirlukast treatment gives (85.7%) protection rate. While salbutamol inhalation gives a protection rate 88%. Only 66.6 % of girls with EIB give an improvement in PEFR values after sodium cromoglycate treatment. A regular measurement of PEFR in school students appears to be a good indicator of EIB, while inhalation of salbutamol 15 minutes before exercise give a good protection against EIB attacks at least for 4 hours.

The effects of aerobic exercise frequencies on liver fibrosis, α-fetoprotein and cytokeratin 19 in experimental type 2 diabetes-induced rats: an immunohistochemistry study

ABSTRACT We investigated using immunohistochemistry the effects of frequency of aerobic exercise on liver fibrosis and measured the expression of the oval cell marker, alpha fetoprotein (AFP), and the hepatocellular carcinoma marker, CK 19, in rats with early-period induced type 2 diabetes (T2DM). Rats were divided into four groups: control sedentary rats, diabetic sedentary rats, diabetic rats with continuous exercise (30 min/day, 5 days/week) and diabetic rats with short periods of exercise (3 x 10 min/day, 5 days/week). T2DM was induced using an intraperitoneal (i.p.) injection of nicotinamide (NA) and streptozotocin (STZ). Liver samples were obtained 8 weeks after injection. Tissue sections were stained with hematoxylin and eosin, periodic acid-Schiff and Masson’s trichrome. We also used immunochemical staining for AFP, smooth muscle actin (α-SMA) and CK19. Continuous and short periods of aerobic exercise produced similar effects during the early period of liver damage in the STZ-NA model, i.e., decreased blood glucose levels and improved body weight, improved liver histology and reduced fibrosis, necrosis and steatosis; and reduced expression of AFP and α-SMA. Moderate aerobic exercise for 150 min/week appeared to reduce early liver damage in a rat model of T2DM.

Current Therapeutic Strategies in Treating Obesity in Children and Adolescents – Review of The Literature

The present paper is a review of current knowledge concerning the most appropriate strategy in the conservative therapy of obese children and adolescents. It presents an account of the combined mode of therapy consisting of behavioral and dietary counseling with appropriate physical activity (also using the support of modern media and devices). The rise in obesity is usually a long-lasting process involving genetic predispositions but also environmental factors which can be modified. The treatment of obesity should be focused on these modified factors and be a lifelong treatment, not merely a short period of exercise or a diet program. Successful therapy depends on the cooperation of the medical team with children and their parents or caregivers.

Urinary Kidney Injury Molecule-1 but Not Urinary Neutrophil Gelatinase Associated Lipocalin Is Increased after Short Maximal Exercise

Background and Aims: Urinary neutrophil gelatinase associated lipocalin (uNGAL) and urinary kidney injury molecule-1 (uKIM-1) are markers of acute kidney injury. The albuminuria is a well-known abnormality after physical exercise. The aim of this study was to investigate changes in uNGAL and uKIM-1 after intensive exercise causing albuminuria. Methods: The study population consisted of 19 participants (10 males and 9 females). The mean age of participants was 35.74 years. All were fit amateur runners; the mean body mass index was 21.99 in females and 24.71 in males. The subjects underwent a graded treadmill exercise test (GXT) according to the Bruce protocol. Maximal oxygen consumption (VO₂max) was measured. Immediately before and after the test urine was collected. Urinary creatinine, albumin, NGAL, and KIM-1 were measured. Albumin to creatinine (ACR), KIM-1 to creatinine (KCR), and NGAL to creatinine (NCR) ratios were calculated. Results: The mean VO₂max was 53.68 in females and 59.54 mL/min/kg in males. Albuminuria and ACR were significantly higher after exercise. An increase in the ACR from 8.82 to 114.35 mg/g (p < 0.01) was observed. uKIM-1 increased significantly after exercise from 849.02 to 1,243.26 pg/mL (p < 0.05). KCR increased from 1,239.1 to 1,725.9 ng/g but without statistical significance (p = 0.07). There were no statistical changes in pre- and post-run uNGAL levels. There was no correlation between post-GXT albuminuria and uKIM-1. Conclusions: uKIM-1 is a very sensitive marker of kidney dysfunction. In our study, uKIM-1 increased significantly after a very short period of exercise. It is not clear if the increase in KIM-1 is caused by post-exercise albuminuria.

Physical Exercise Improves Cognitive Outcomes in 2 Models of Transient Cerebral Ischemia.

Preclinical studies suggest that exercise can enhance cognition after cerebral ischemia but often use long training regiments and test cognition during or acutely after training. The cognitive changes may result from enhanced physical fitness and may only provide acute benefit. We sought to determine whether a short period of exercise after cerebral ischemia could improve cognitive outcomes when measured days after completion of exercise training in 2 cerebral ischemia models. Focal or global cerebral ischemia was induced in Sprague-Dawley rats. Rats recovered (3-4 days) then were subject to no exercise (0 m/min), mild (6 m/min), moderate (10 m/min), or heavy (15-18 m/min) treadmill exercise (5-6 days). Cognition was tested 8 to 10 days after the last exercise session with hippocampal-dependent contextual fear conditioning. A short training period of moderate exercise enhanced cognitive function for a week after exercise completion in both models of cerebral ischemia. Utilization of this exercise paradigm can further the elucidation of exercise-mediated factors involved in cognitive recovery independent of changes in physical fitness.

Urinary schistosomiasis among primary school children at Al‐Takamul area, eastern Khartoum state‐Sudan: An example for urban schistosomiasis

Background : Urinary Schistosomiasis, caused by Schistosoma haematobium, is classically associated with rural areas that provide the hospitable condition for transmission. With the recent massive internal displacement, new communities were settled and created urban extensions to the big cities. These extensions bridged the space between the urban areas and the agricultural schemes around them. The area selected for this study is a good example for these settings. Given that the new population was displaced from known endemic areas, the transmission cycle seems to be completed. Objective: The aim of this study is to identify the frequency of urinary schistosomiasis among school children form Al-Takamul, which is a suburban district located in the Eastern Khartoum State. Materials and Methods : 150 school children were enrolled in this study, all were boys. Half of them were 11 year old or less. 20 ml of fresh voided urine (including terminal urine) were collected from each participant after a short period of exercise. Following physical and chemical examination, 10 ml sample of each specimen was centrifuged and the sediment was then thoroughly examined under the microscope. Results: 22% of study populations were found infected with S. haematobium (sensitivity 96.97%, specificity 100%), 87.9% of them were more than 11 year old (RR 2.23). 27.27% of the infected individuals had a history of past infection. 84.8% of infected population knew about schistosomiasis and its transmission. The results suggested that urban schistosomiasis is prevalent in the study area and it is presented with a distinguished pattern, that is, it is prevalent among children over 11 years old, and it is associated with knowledge but no awareness. Conclusion : The study area may be a potential focal point of urinary schistosomiasis transmission for neighboring areas. Massive survey and preventive chemotherapy is urgent.

Neuromuscular, metabolic and ventilatory fatigue threshold from an incremental cycling test using 1-min exercise periods

Aim: Extensive research has been directed towards the identification of the threshold that demarcates fatiguing from non-fatiguing exercise during an incremental workout on a cycle ergometer. As the exercise intensity increases, fatigue compromises not only the cardiovascular and respiratory systems, but also the neuromuscular system. The objective of this work was to calculate the neuromuscular fatigue threshold from surface electromyographic amplitude (EMG-FT) and determine possible associations between this threshold and the metabolic (onset of blood lactate accumulation, OBLA) and ventilatory (ventilatory threshold, VT, and respiratory compensation point, RCP) thresholds.  Methods: Sixteen cyclists performed incremental cycle ergometer rides to exhaustion with bipolar surface sEMG signals recorded from the vastus lateralis. The participants were road cyclists engaged in regular training and amateur road races. On average, cyclists trained at least four times a week covering a weekly distance ranging between 400 and 600 km, plus competition or Sunday training. Cyclists had a national competitive experience of 4.3 (1.7) years and had performed an average of 20,000 km riding. Before the incremental exercise test started, cyclists performed 5 min of unloaded cycling. The test was initiated at a workload of 125 W and the load was increased by 25 W every 1 min until the subjects could no longer continue to exercise (Fig. 1a). At this time, the power achieved was referred to as the maximal power. To calculate the EMG-FT, the deVries’ model was employed using 1-min exercise periods. Blood samples were taken every two minutes during the test. OBLA was calculated as the power output corresponding to a blood lactate concentration of 4.0 mmol/L. During the incremental exercise, breath by breath analysis was performed using a turbine flow-meter connected to a face mask and data of oxygen uptake and carbon dioxide production and ventilatory parameters. One-way repeated-measures ANOVA was used to determine whether there were significant differences in average power output among the EMG-FT, OBLA, VT, and RCP. Pearson correlation coefficients were calculated to determine the relationships among EMG-FT, OBLA, VT, and RCP.  Results: The maximal power tolerated was 403.8 ± 36.5 W. The power output at EMG-FT (372 ± 25 W) was comparable (P>0.05) to that of RCP (381 ± 36 W), but significantly higher (P 0.05), but it was positively correlated with those of VT (0.78, P<0.001) and RCP (0.85, P<0.001).  Conclusions: Our results do not support the existence of a relationship between EMG-FT and lactate concentration. A significant correlation was found between the sEMG-based threshold and gas exchange thresholds, although this correlation may not be causative. Second, application of deVries’ model using of 1-min exercise periods could result in overestimation of the fatigue threshold since such short exercise periods could be insufficient to detect EMG signs of neuromuscular fatigue

The influence of a single bout of aerobic exercise on short-interval intracortical excitability

Regular physical activity can have positive effects on brain function and plasticity. Indeed, there is some limited evidence that even a single bout of exercise may promote plasticity within the cortex. However, the mechanisms by which exercise acutely promotes plasticity are not clear. To further explore the effects of acute exercise on cortical function, we examined whether a single bout of exercise was associated with changes in cortical excitability and inhibition. Using standard techniques, cortical stimulus-response curves [90% resting motor threshold (RMT)-150% RMT] were investigated in nine subjects (four females, 31.1 ± 11.7 years) and short-interval intracortical inhibition (SICI) [interstimulus interval 2 ms and 3 ms, conditioning intensities of 80% active motor threshold (AMT) and 90% AMT] in 13 subjects (six females, 28.4 ± 5.1 years) before and at 0 and 15 min following 30 min of ergometer cycling at low-moderate or moderate-high intensity. There were no changes in cortical excitability following exercise but less SICI at both 0 and 15 min post-exercise (F [2, 24] = 7.7, P = 0.003). These findings show that a short period of exercise can transiently reduce SICI. Such a change in inhibition after exercise may contribute to the development of a cortical environment that would be more optimal for plasticity and may partially explain previous findings of enhanced neuroplasticity following low-intensity exercise.

Do Older Females Store More Heat than Younger Females during Exercise in the Heat?

Aging is associated with a reduction in the body's capacity to dissipate heat. To date, few studies have examined age-related changes in thermoregulatory function during short exercise periods in the heat in older females. This study aimed to investigate the effects of age on whole-body heat loss during intermittent exercise in the heat in young and older females. Direct and indirect calorimetry was used to measure whole-body evaporative heat loss (EHL), change in body heat content, and metabolic heat production. Eleven young (Y) (mean ± SD age = 24 ± 4 yr) and 13 older (O) (51 ± 8 yr) females matched for body surface area (Y, 1.72 ± 0.15; O, 1.75 ± 0.12 m²) and fitness (V(˙)O(2max)) (Y, 36.7 ± 6.8 mL O₂·kg⁻¹·min⁻¹; O, 33.8 ± 8.0 mL O₂·kg⁻¹·min⁻¹) performed four bouts of 15-min cycling (Ex1, Ex2, Ex3, and Ex4) at a constant rate of heat production (300 W) at 35°C and 20% relative humidity. Each exercise bout was separated by 15 min of rest. EHL was reduced in O compared with Y during Ex1 (O, 199 ± 6 W; Y, 240 ± 9 W; P = 0.001), Ex2 (O, 238 ± 4 W; Y, 261 ± 9 W, P = 0.023), and Ex3 (O, 249 ± 4 W; Y, 274 ± 11 W; P = 0.040). EHL was not different between groups during Ex4 or during the recovery periods. Older females had a greater change in body heat content compared with young females (O, 270 ± 20 kJ; Y, 166 ± 20 kJ; P = 0.001). These findings suggest that older females have a lower capacity for whole-body EHL compared with younger females during short intermittent exercise in the heat performed at a fixed rate of metabolic heat production.

The Beneficial Effects of Early Short‐Term Exercise in the Offspring of Obese Mothers are Accompanied by Alterations in the Hypothalamic Gene Expression of Appetite Regulators and FTO (Fat Mass and Obesity Associated) Gene

Maternal overnutrition is implicated in the development of adult metabolic disease, and has been shown to alter the expression of genes involved in energy homeostasis. In the present study, we aimed to test whether a short period of voluntary exercise, followed by a sedentary period, would regulate hypothalamic markers involved in appetite. Adult female Sprague-Dawley rats were fed either normal chow or high-fat diet (HFD) ad lib. for 5 weeks, mated and continued on their assigned diet during gestation/lactation. At weaning males, were separated into chow or HFD groups; half were exercised (running wheels), whereas the remainder were sedentary. At week 10, wheels were removed and rats remained sedentary for 5 weeks, prior to tissue collection. Maternal obesity increased offspring adiposity at 15 weeks and this was exacerbated by postnatal HFD (P < 0.05). Body weight and fat mass were reduced in offspring of obese mothers if they exercised, and this was maintained even after 5 weeks without exercise. At 15 weeks, fasting plasma insulin, leptin and triglyceride concentrations were significantly reduced by exercise in offspring of lean and obese mothers consuming chow, with little benefit in those consuming HFD. Hypothalamic mRNA expression of pro-opiomelanocortin was increased by exercise but only in offspring of lean mothers. Exercise reduced hypothalamic FTO (fat mass and obesity associated) mRNA in offspring of lean dams regardless of diet. A short period of exercise early in life had lasting beneficial effects on body weight, adiposity and hormone profile of male offspring from obese and lean dams, despite being followed by a period of inactivity. The effects of exercise on hypothalamic appetite regulators were more marked in offspring of lean dams.