Single Bout Of Exercise Research Articles

Time Spent Near Maximal Oxygen Uptake During Exercise at Different Regions of the Severe-Intensity Domain.

Faricier, R, Fleitas-Paniagua, PR, Iannetta, D, Millet, GY, Keir, DA, and Murias, JM. Time spent near maximal oxygen uptake during exercise at different regions of the severe-intensity domain. J Strength Cond Res XX(X): 000-000, 2024-This study applied the critical power (CP) model and several bouts of constant-power exercise within different regions of the severe-intensity domain to determine whether there exists an optimal intensity to maximize time spent near V̇o2peak. Subjects visited the laboratory 9 times. After a ramp-incremental test to determine V̇o2peak and peak power output (POpeak), 9 active individuals (5 females) performed 4 constant-power bouts to task failure between 65 and 100%POpeak to estimate CP and total finite work above CP (W'). Subjects then completed 4 additional exhaustive trials predicted to result in task failure in ∼3, 6, 9, and 12 minutes. Time spent at V̇o2peak was calculated as the duration at which V̇o2 ≥ 95% of the trial-specific V̇o2peak. The level of significance set for the study was p < 0.05. Mean CP and W' were 201 ± 48 W and 17.6 ± 8.4 kJ, respectively. For each bout, time to task failure was 2.7 ± 0.5, 6.3 ± 0.6, 9.5 ± 1.2, and 13.1 ± 3.1 minutes for the 3-, 6-, 9-, and 12-minute conditions. Time spent at V̇o2peak during the 3-minute trial (45 ± 22 seconds) was shorter than during the 9-minute (204 ± 104 seconds; p = 0.002) and 12-minute trials (260 ± 155 seconds; p < 0.001). The 6-minute trial (117 ± 46 seconds) had shorter (p = 0.005) time spent at V̇o2peak compared with the 12-minute trial. At least when performing single bouts of exercise, intensities closer to CP (i.e., those sustainable for ∼9 minutes or longer) seem preferable compared with POs in the upper regions of the severe-intensity domain to maximize time at V̇o2peak.

Skeletal muscle from TBC1D4 p.Arg684Ter variant carriers is severely insulin resistant but exhibits normal metabolic responses during exercise.

In the Greenlandic Inuit population, 4% are homozygous carriers of a genetic nonsense TBC1D4 p.Arg684Ter variant leading to loss of the muscle-specific isoform of TBC1D4 and an approximately tenfold increased risk of type 2 diabetes1. Here we show the metabolic consequences of this variant in four female and four male homozygous carriers and matched controls. An extended glucose tolerance test reveals prolonged hyperglycaemia followed by reactive hypoglycaemia in the carriers. Whole-body glucose disposal is impaired during euglycaemic-hyperinsulinaemic clamp conditions and associates with severe insulin resistance in skeletal muscle only. Notably, a marked reduction in muscle glucose transporter GLUT4 and associated proteins is observed. While metabolic regulation during exercise remains normal, the insulin-sensitizing effect of a single exercise bout is compromised. Thus, loss of the muscle-specific isoform of TBC1D4 causes severe skeletal muscle insulin resistance without baseline hyperinsulinaemia. However, physical activity can ameliorate this condition. These observations offer avenues for personalized interventions and targeted preventive strategies.

Subacute Effects of Moderate-Intensity Aerobic Exercise in the Fasted State on Cell Metabolism and Signaling in Sedentary Rats.

Background: Physical inactivity induces insulin resistance (IR) and metabolic imbalances before any significant changes in adiposity. Recent studies suggest that the beneficial effects of exercise can be potentiated if performed while fasting. This work aimed to compare the subacute effects of fed- and fasted-state single-bout exercise on biochemical parameters and cellular signaling in the metabolism. Methods: The animals were allocated into fed rest (FER), fasting rest (FAR), fed exercise (FEE), and fasting exercise (FAE) groups. The exercise protocol was a 30 min treadmill session at 60% of V˙O2max. The fasting groups fasted for 8 h before exercise and were killed after 12 h post-exercise. Results: Soleus glycogen concentration increased only in the fasting groups, whereas the triglyceride (TGL) content increased in brown adipose tissue (BAT) and liver in the FAE. The FAE showed decreased plasma total cholesterol concentration compared withthe FAR group. Immunocontent of HSP70, SIRT1, UCP-1, and PGC1-α did not change in any tissue investigated. Conclusions: Our results indicate that physical exercise while fasting can have beneficial metabolic effects on sedentary animals. Remarkably, in the FAE group, there was a reduction in total plasma cholesterol and an increase in the capacity of BAT to metabolize and store nutrients in the form of TGLs.

Exaggerated Blood Pressure Response to Exercise Is a Risk of Future Hypertension Even in Healthy, Normotensive Young Individuals—Potential Preventive Strategies for This Phenomenon?

Physical activity and regular exercise are well known to reduce the risks of cerebrovascular and cardiovascular diseases, leading the American College of Sports Medicine to endorse the concept that “exercise is medicine”. However, a single bout of exercise temporarily raises arterial blood pressure (BP) to meet the metabolic demands of working muscle, and this BP response is particularly exaggerated in older adults and patients with cardiovascular conditions, such as hypertension, resulting in an exaggerated BP response during exercise. This presents a paradox: while regular exercise is crucial for preventing these diseases, excessively high BP responses during exercise could increase the risk of vascular damage. The mechanisms underlying this exaggerated BP response during exercise remain unclear, and effective exercise regimens for these populations have yet to be established. Currently, low-intensity exercise is recommended; however, its efficacy in disease prevention is uncertain. Notably, even among healthy individuals, there is significant variation in the BP response to exercise. Some healthy individuals, despite having normal resting BP, exhibit an exaggerated BP response during physical activity. Importantly, these individuals are often unaware that their BP becomes excessively elevated during physical activity. Repeated exposure to these heightened BP responses through regular physical activity may increase their long-term risk of cardiovascular disease. How can we prevent disease development in these individuals while still ensuring the effectiveness of exercise? Some studies have shown that individuals with a family history of hypertension may experience this phenomenon even in children and adolescents. Additionally, left ventricular hypertrophy contributes to an exaggerated BP response to exercise, suggesting a possible genetic influence. Conversely, other reports indicate that factors such as arterial stiffness, obesity, and low exercise capacity also contribute to this exaggerated response. Our recent preliminary data suggest that the cognitive benefits of exercise may be diminished in individuals who exhibit an exaggerated BP response during exercise. This implies that individuals with an exaggerated BP response, despite having normal resting BP, may not fully benefit from exercise. In this perspective paper, we review the physiological aspects of this phenomenon and explore strategies to address it. Additionally, we discuss BP responses in athletes within this content. Our goal is to prevent disease while maximizing the benefits of exercise for healthy individuals with an exaggerated BP response, as well as for elderly and cardiovascular patients.

Effect of an acute session of intermittent exercise on trimethylamine N-oxide (TMAO) production following choline ingestion

IntroductionTrimethylamine N-oxide (TMAO) is a gut bacteria-dependent metabolite associated with poor cardiovascular health. Exercise is a known cardioprotective activity but the impact of an acute bout of exercise on TMAO production is unknown.Objectives/MethodsThis study assessed choline-derived production of TMAO following a single bout of intermittent exercise in a young, healthy cohort.ResultsCholine supplemented after either exercise or a time-matched resting period demonstrated a similar increase in circulating TMAO across an 8-hour period.ConclusionThis suggests that a single bout of intermittent exercise does not alter gut microbial metabolic behaviour and thus does not provide additional cardioprotective benefits related to blood levels of TMAO.

The Effect Of A Single Bout Of Sub-symptom Threshold Aerobic Exercise On Executive Function In Acutely Concussed Athletes

The Effect Of A Single Bout Of Sub-symptom Threshold Aerobic Exercise On Executive Function In Acutely Concussed Athletes

A Single Bout of On-Ice Training Leads to Increased Interlimb Asymmetry in Competitive Youth Hockey Athletes.

Interlimb asymmetry (ILA) refers to an anatomical or physiological imbalance between contralateral limbs, which can influence neuromuscular function. Investigating the influence of neuromuscular fatigue on ILA may be critical for optimizing training programs, injury rehabilitation, and sport-specific performance. The purpose of this study was to determine if a single bout of ice hockey-specific exercise creates or exacerbates lower-limb ILA. Before and after an on-ice training session, 33 youth ice-hockey athletes (14.9 [1.7]y; 11 females) performed 3 repetitions of a maximal vertical countermovement jump (CMJ), an eccentric hamstring contraction, and maximal isometric hip adduction and abduction contractions. Force- and power-related variables were analyzed to determine limb-specific neuromuscular function. The on-ice session reduced maximal isometric hip adduction (left: 7.3% [10.3%]; right: 9.5% [9.6%]) and abduction (left: 4.9% [6.9%]; right: 5.0% [8.1%]) force, but did not impair (P ≥ .10) CMJ performance (jump height, relative peak power, braking duration, and total duration). After the on-ice session, ILA was greater for CMJ propulsive impulse (6.3% [2.9%] vs 5.1% [2.6%]), CMJ braking rate of force development (19.3% [7.6%] vs 15.2% [6.4%]), and peak isometric hip adduction force (6.7% [5.5%] vs 6.1% [4.1%]). In conclusion, hockey-specific exercise leads to increased ILA for multiple force-related metrics, which may be a compensatory mechanism to maintain bilateral task performance when fatigued.

Mood Benefits Of A Single Bout Of Exercise In Pregnancies Complicated By Fetal Growth Restriction

Mood Benefits Of A Single Bout Of Exercise In Pregnancies Complicated By Fetal Growth Restriction

A single bout of physical exercise improves 1-hour post-load plasma glucose in healthy young adults.

Physical exercise is a key component in the treatment of type 2 diabetes and plays an important role in maintaining a healthy glucose metabolism even in healthy subjects. To date, no studies have investigated the effect of a single bout of aerobic physical exercise on glucose metabolism in young, moderately active, healthy adults. We performed an OGTT 7 days before and 24h after a single bout of physical exercise, to evaluate 1-hour post-load plasma glucose and surrogate indexes of insulin sensitivity and insulin secretion. Glucose levels were significantly reduced after exercise at baseline and one hour after glucose load; similarly, insulin was significantly lower 1h after glucose load. We found a significant increase in the Matsuda index, confirmed by OGIS index, QUICKI index, and by significant reduction in HOMA-IR. Conversely, we observed a trend to increase in HOMA-B. This is the first study to evaluate the effect of a single bout of exercise on 1-hour glucose levels following OGTT. We found a significant reduction in 1-hour glucose levels following OGTT together with an increased insulin sensitivity. A single 30-minute bout of aerobic exercise also seemed to improve the insulin secretion pattern. Modifications in beta cell secretory capacity during exercise are likely secondary to an improvement in insulin action in insulin dependent tissues.

Interleukin-15 and high-intensity exercise: relationship with inflammation, body composition and fitness in cancer survivors.

Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth. These anti-oncogenic effects of exercise were associated with the exercise-mediated release of myokines such as interleukin (IL)-15. However, no study has quantified the acute IL-15 response in human cancer survivors, and whether physiological adaptations to exercise training (i.e. body composition and cardiorespiratory fitness) influence this response. In the present study breast, prostate and colorectal cancer survivors (n=14) completed a single bout of high-intensity interval exercise (HIIE) [4×4min at 85-95% heart rate (HR) peak, 3min at 50-70% HR peak] before and after 7months of three times weekly high-intensity interval training (HIIT) on a cycle ergometer. At each time point venous blood was sampled before and immediately after HIIE to assess the acute myokine (IL-15, IL-6, IL-10, IL-1ra) responses. Markers of inflammation, cardiorespiratory fitness and measures of body composition were obtained at baseline and 7months. An acute bout of HIIE resulted in a significant increase in IL-15 concentrations (pre-intervention: 113%; P=0.013, post-intervention: 102%; P=0.005). Post-exercise IL-15 concentrations were associated with all other post-exercise myokine concentrations, lean mass (P=0.031), visceral adipose tissue (P=0.039) and absolute peak (P=0.032). There was no significant effect of 7months of HIIT on pre- or post-HIIE IL-15 concentrations (P>0.05). This study demonstrates HIIE is a sufficient stimulus to increase circulating IL-15 and other myokines including IL-6, IL-10 and IL-1ra which may be clinically relevant in the anti-oncogenic effect of exercise and repetitive exposure to these effects may contribute to the positive relationship between exercise and cancer recurrence. KEY POINTS: Exercise has been demonstrated to reduce the risk of cancer recurrence. Pre-clinical murine and in vitro models have demonstrated that exercise suppresses tumour and cancer cell growth, mediated by exercise-induced myokines (IL-6 and IL-15). High-intensity interval exercise significantly increased myokines associated with the anti-oncogenic effect of exercise and the magnitude of response was associated with lean mass, but training did not appear to influence this response. Given IL-15 has been implicated in the anti-oncogenic effect of exercise and is being explored as an immunotherapy agent, high-intensity interval exercise may improve outcomes for people living beyond cancer through IL-15-mediated pathways. Interventions that increase lean mass may also enhance this response.

Characterising how a single bout of exercise in people with myeloma affects clonal plasma cell and immune effector cell frequency in blood, and daratumumab efficacy in vitro

Multiple myeloma is a haematological cancer characterised by the accumulation of clonal plasma cells in the bone marrow and is commonly treated with daratumumab, an anti-CD38 monoclonal antibody immunotherapy. Daratumumab often fails to induce stringent complete responses, due in part to resistance to antibody-dependent cellular cytotoxicity (ADCC) exerted by natural killer (NK)-cells and monocytes. Exercise bouts undertaken by healthy people induce lymphocytosis in blood, including to NK-cells and B-cells, but the effects of exercise are unknown in myeloma patients. In addition, whether exercise mobilises plasma cells has not been adequately investigated, and as such the potential impact of exercise on daratumumab treatment is unclear. In this exploratory pilot study, n = 16 smouldering multiple myeloma participants enrolled and n = 9 completed the study which comprised a bout of cycling 15% above anaerobic threshold for ∼30-min, with blood samples collected pre-, immediately post-, and 30-min post-exercise. Peripheral blood mononuclear cells were isolated from blood samples and incubated with the RPMI-8226 plasmacytoma cell line, with or without the presence of daratumumab to determine specific lysis using a calcein-release assay. Daratumumab-mediated cell lysis increased from 18.8% to 23.2% pre- to post-exercise, respectively (p < 0.001), owing to an increased frequency of CD3−CD56+CD16+ NK-cells (+348%), HLA-DR+CD14dimCD16+ monocytes (+125%), and HLA-DR+CD14+CD32+ monocytes (+41%) in blood (p < 0.01). However, overall, total plasma cells (CD38+CD138+) nor clonal plasma cells (CD38brightCD138+CD45−/dimCD19− with light-chain restriction) increased in blood (p > 0.05). Notably, we observed a 305% increase in NK-cells expressing CD38, the daratumumab target antigen, which might render NK-cells more susceptible to daratumumab-mediated fratricide – whereby NK-cells initiate ADCC against daratumumab-bound NK-cells. In conclusion, exercise modestly improved the efficacy of daratumumab-mediated ADCC in vitro. However, plasma cells were largely unchanged, and NK-cells expressing CD38 – the daratumumab target antigen – increased in blood. Future research should consider the optimal timings of exercise during daratumumab treatment in myeloma to avert exacerbation of daratumumab-mediated NK-cell lysis.

Effects of Melatonin on Exercise-Induced Oxidative Stress in Adults with Obesity Undergoing a Multidisciplinary Body Weight Reduction Program.

Background: Obesity is characterized by increased oxidative stress, which, in a vicious circle, promotes chronic low-grade inflammation. Melatonin, a well-documented antioxidant, might be useful as a supplement to enhance the cardiometabolic benefits of any body weight reduction program (BWRP). Objectives/Methods: The present study aimed to evaluate the post-exercise oxidative stress and inflammation in a group of subjects with obesity treated with melatonin (2 mg/die) or placebo, undergoing a 2-week BWRP, with the administration of a single bout of acute exercise at the start and the end of the protocol (G1-G15). Results: Eighteen adults with obesity were enrolled and distributed to the two arms of the study: the melatonin group (F/M: 7/2; age: 27.8 ± 5.6 years; body mass index [BMI]: 43.0 ± 4.9 kg/m2) and the placebo group (F/M: 6/3; age: 28.8 ± 5.0 years; BMI: 42.8 ± 4.0 kg/m2). BWRP induced a decrease in BMI and waist circumference (WC) in both groups; plasma glucose, blood glycated hemoglobin (HbA1c), and neutrophil to lymphocyte ratio (NLR) were reduced only in the placebo group. Importantly, plasma biological antioxidant potential (BAP) increased throughout BWRP. Paradoxically, melatonin enhanced post-exercise production of plasma derivatives of reactive oxygen metabolites (d-ROMs) and erythrocytic glutathionyl-Hb (HbSSG) (at G1 and G15). Finally, differently from the placebo group, melatonin-treated subjects did not exhibit the BWRP-induced decrease in plasma levels of interleukin-6 (IL-6), before and after exercise, at the end of two weeks (G15). Conclusions: Melatonin is presumably an antioxidant with "conditional" prooxidant actions. The use of melatonin as a supplement in subjects with obesity might be deleterious due to the abolishment of BWRP-induced cardiometabolic benefits.

A single bout of resistance exercise triggersmitophagy, potentially involving the ejection of mitochondria in human skeletal muscle.

The present study aimed to investigate the effects of a single bout of resistance exercise on mitophagy in human skeletal muscle (SkM). Eight healthy men were recruited to complete an acute bout of one-leg resistance exercise. SkM biopsies were obtained one hour after exercise in the resting leg (Rest-leg) and the contracting leg (Ex-leg). Mitophagy was assessed using protein-related abundance, transmission electron microscopy (TEM), and fluorescence microscopy. Our results show that acute resistance exercise increased pro-fission protein phosphorylation (DRP1Ser616) and decreased mitophagy markers such as PARKIN and BNIP3L/NIX protein abundance in the Ex-leg. Additionally, mitochondrial complex IV decreased in the Ex-leg when compared to the Rest-leg. In the Ex-leg, TEM and immunofluorescence images showed mitochondrial cristae abnormalities, a mitochondrial fission phenotype, and increased mitophagosome-like structures in both subsarcolemmal and intermyofibrillar mitochondria. We also observed increased mitophagosome-like structures on the subsarcolemmal cleft and mitochondria in the extracellular space of SkM in the Ex-leg. We stimulated human primary myotubes with CCCP, which mimics mitophagy induction in the Ex-leg, and found that BNIP3L/NIX protein abundance decreased independently of lysosomal degradation. Finally, in another human cohort, we found a negative association between BNIP3L/NIX protein abundance with both mitophagosome-like structures and mitochondrial cristae density in the SkM. The findings suggest that a single bout of resistance exercise can initiate mitophagy, potentially involving mitochondrial ejection, in human skeletal muscle. BNIP3L/NIX is proposed as a sensitive marker for assessing mitophagy flux in SkM.

Abstract P126: Exercise-Induced Changes in Skeletal Muscle of Patients with Chronic Kidney Disease on Maintenance Hemodialysis

Background: Chronic kidney disease (CKD) patients on maintenance hemodialysis (MHD) often experience sarcopenia and functional decline. The impact of exercise and inactivity on sarcopenia in CKD is poorly understood. We aimed to identify exercise-responsive genes that are differentially expressed between controls and patients on MHD. We also aim to investigate the changes in gene expression in skeletal muscle following a resistance exercise program in patients on MHD. Methods: In a cross-sectional study, we performed RNA sequencing analysis in skeletal muscle biopsies from two groups (matched for age, gender, body mass index, and history of diabetes): controls (n=13) and patients on maintenance hemodialysis (MHD, n=10). In a separate cohort, we conducted a 12-week intradialytic resistance training in seven patients on MHD. Skeletal muscle biopsies were collected pre- and post-intervention to assess the acute (before and after a single bout of exercise) and chronic (after 12 weeks) effects of exercise. Total RNA was extracted and used to construct libraries for RNA sequencing using the Illumina NovaSeq 6000 system. Differentially expressed genes (DEGs) were identified based on a false discovery rate (FDR) of less than 0.05 and a fold change greater than 1.5. Exercise and inactivity-responsive genes in non-CKD populations identified in the MetaMEx (www.metamex.eu) were used as reference. Results: We found significant DEGs between the control and MHD that were affected by exercise or inactivity according to MetaMEx. These genes and fold changes between control and MHD groups are depicted in Table 1. In the exercise intervention cohort, we observed no significant differences in the expression of these genes either acutely (Figure 1A) or 12 weeks after the exercise intervention (Figure 1B). Conclusion: We found many DEGs related to exercise and inactivity between patients on MHD and controls; however, resistance training does not significantly alter skeletal muscle gene expression. Future studies should explore alternative exercise interventions, such as HIIT exercise, aerobic training, combined aerobic and resistance training, or longer duration programs, to determine if these approaches can effectively modulate gene expression and improve sarcopenia and frailty in this population.

Investigating the acute effect of low and moderate intensity aerobic exercise on whole-body task learning and cognition in young adults.

Recent studies have shown that a single bout of exercise has acute improvements on various forms of memory, including procedural motor learning, through mechanisms such as the plasticity-promoting effect. This study aimed to examine (1) the acute effects of timing and intensity of aerobic exercise on the acquisition and retention of motor learning in healthy adults, (2) the effect of sleep quality of the night before and after acquisition on motor learning, and (3) the acute effects of low and moderate-intensity aerobic exercise on cognitive functions. Seventy-five healthy adults were divided into five groups: Two groups performed low or moderate intensity aerobic exercise before motor practice; two groups performed low or moderate intensity aerobic exercise after motor practice; the control group only did motor practice. Low- and moderate-intensity exercises consisted of 30 min of running at 57%-63% and 64%-76% of the maximum heart rate, respectively. Motor learning was assessed using a golf putting task. The sleep quality of the night before and after the acquisition was evaluated using the Richard Campbell Sleep Questionnaire. Cognitive function was assessed before and after aerobic exercise using the Paced Auditory Serial Acquisition Task test. Results indicated that all groups demonstrated acquisition, 1-day and 7-day retention at a similar level (p > 0.05). Regression analysis revealed no significant relationship between sleep quality on the night before the experimental day and total acquisition (p > 0.05). However, a positive correlation was found between the sleep quality on the night of the experimental day and both 1-day and 7-day retention (p < 0.05). A single bout of low or moderate acute exercise did not modify motor skill acquisition and retention. Other results showed the importance of night sleep quality on the retention and proved that a single bout of moderate intensity exercise was associated with improved cognitive function.

Central blood pressure and peripheral augmentation index following acute submaximal arm versus leg exercise.

Aerobic exercises like running and cycling may lower cardiovascular disease (CVD) risk through favorable effects on central blood pressure and vascular function. Arm ergometry is a popular exercise modality used in rehabilitation settings, but little is known regarding the central hemodynamic and vascular effects of this form of exercise. To compare the acute effects of leg versus arm exercise on central blood pressure and vascular function. Twenty-one participants (n = 11 female, Age 21 ± 3, BMI 24.5 ± 3.2kg/m2) completed two visits to the Human Performance Laboratory. Central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), and peripheral augmentation index (pAIx) were measured using a brachial oscillometric blood pressure cuff with measures being taken before and after 20min of acute moderate-intensity (submaximal) arm or leg cycling exercise. There was a condition-by-time interaction for pAIx (p = 0.011). pAIx slightly increased following arm exercise but significantly decreased following leg exercise. There was a condition-by-time interaction for cDBP (p = 0.011). cDBP significantly decreased following arm exercise but increased immediately following leg exercise. There was no condition-by-time interaction for cSBP (p = 0.721). There were similar acute increases in cSBP immediately post-exercise for both conditions. Arm exercise increased pAlx and decreased cDBP compared to leg exercise. As an increase in pAIx may increase left ventricular work and a reduction in cDBP may reduce coronary perfusion pressure, these findings suggest that a single bout of arm exercise may not have the same favorable acute effect on central hemodynamic load as a single bout of leg exercise.

Oxygen Consumption During Moderate-Intensity Interval Exercise in Overweight Young Adults

Background: Overweight and obesity have become a problem for younger generations, so weight management must be introduced. Moderate-intensity interval training (MIIT) has been recommended for aging and obese populations because it is friendly and accessible. However, little information is known about the physiological response during moderate-interval intensity exercise, especially for overweight and obese persons. Objectives: To evaluate cardiorespiratory alteration upon a single bout of MIIT exercise among sedentary, overweight young Thai adults. Methods: Fifteen overweight young adults (8 males and 7 females, body mass index between 25.0 - 29.9 kg/m2, aged between 18 - 25 years) underwent cycling ergometry for 45 minutes (warm-up 5 minutes; 3 × 5 minutes at 20 - 40% of heart rate reserve and 5 minutes at 50 - 60%; cool down 10 minutes). A gas analyzer and limb lead electrocardiogram were used to record oxygen consumption (V̇O2), heart rate (HR), and dioxide production (V̇CO2) throughout the experiment. Results: During the 45-minute MIIT exercise protocol, the participants consumed 25.1 ± 8.1 L, equal to approximately 530 ± 171 kJ. As expected, heart rate, O2 uptake, and CO2 production increased during moderated-intensity exercise and declined during low-intensity exercise. A low to moderate duration ratio of 1: 1 was sufficient to return both O2 consumption and CO2 production to their stage level, but not for heart rate. Although there was a very linear relationship between V̇O2 and heart rate for the overall period (0.761 ± 0.090), the correlation was weaker when selectively computed during low (0.549 ± 0.161) or moderate exercises (0.658 ± 0.105). Interestingly, RER larger than one during moderate-intensity exercise indicated the possibility of high acid accumulation. Conclusions: The MIIT protocol in the present study provided a responsive effect on overweight persons toward anaerobic metabolism but was a little aggressive.

MR Assessment of Acute Changes of Cerebral Perfusion, Metabolism, and Blood-Brain Barrier Permeability in Response to Aerobic Exercise.

It remains unclear how a single bout of exercise affects brain perfusion, oxygen metabolism, and blood-brain barrier (BBB) permeability. Addressing this unresolved issue is essential to understand the acute changes in cerebral physiology induced by aerobic exercise. To dynamically monitor the acute changes in cerebral physiology subsequent to a single aerobic exercise training session using noninvasive MRI measurements. Prospective. Twenty-three healthy participants (18-35 years, 10 females/13 males) were enrolled and divided into 10-minute exercising (N = 10) and 20-minute exercising (N = 13) groups. 3.0 T/Phase Contrast (PC) MRI (gradient echo), T2-Relaxation-Under-Spin-Tagging (TRUST) MRI (gradient echo EPI), Water-Extraction-with-Phase-Contrast-Arterial-Spin-Tagging (WEPCAST) MRI (gradient echo EPI) and T1-weighted magnetization-prepared-rapid-acquisition-of-gradient-echo (MPRAGE) (gradient echo). A baseline MR measurement plus four repeated MR measurements immediately after 10 or 20 minutes moderate running exercise. MR measurements included cerebral blood flow (CBF) as measured by PC MRI, venous oxygenation (Yv) and cerebral metabolic rate of oxygen (CMRO2) as assessed by TRUST MRI, water extraction fraction (E), and BBB permeability-surface-area product (PS) as determined by WEPCAST MRI. The time dependence of the physiological parameters was studied with a linear mixed-effect model. Additionally, pairwise t-tests comparison of the physiological parameters at each time point was conducted. A P-value of <0.05 was considered statistically significant. There was an initial drop (8.22 ± 2.60%) followed by a recovery in CBF after exercise, while Yv revealed a significant decrease (6.37 ± 0.92%), i.e., an increased oxygen extraction, and returned to baseline at later time points. CMRO2 showed a trend of increase (5.68 ± 3.04%) and a significant interaction between time and group. In addition, E increased significantly (3.86% ± 0.89) and returned to baseline level at later time points, while PS remained elevated (13.33 ± 4.79%). A single bout of moderate aerobic exercise can induce acute alterations in cerebral perfusion, metabolism, and BBB permeability. 2 TECHNICAL EFFICACY: Stage 2.

Effects of Exhaustive Exercise on Adiponectin and High-Molecular-Weight Oligomer Levels in Male Amateur Athletes.

Physical activity promotes metabolic health and prevents lifestyle-related diseases. Adiponectin is specifically produced by adipose tissue and comes in three forms, differing in terms of weight: trimers (LMW), hexamers (MMW), and high-molecular-weight (HMW) oligomers. The oligomers are associated with the beneficial effects of adiponectin. In this study, we aimed to investigate the impact of a single bout of exhaustive exercise on adiponectin expression in 25 male amateur athletes, divided into two groups, one comprising young adults (YAs) (n = 15), and the other comprising middle-aged adults (MAs) (n = 10). Body fat was estimated through skinfold thickness. Adiponectin levels were assessed at baseline and at 15 min and 24 h post-exercise, while HMW oligomer levels were evaluated at baseline and at 24 h post-exercise. We observed a significant increase in total adiponectin at both 15 min and 24 h after exercise, with there being a more evident effect among the YA subjects. HMW oligomers also increased significantly after exercise both in the total sample and among the YA subjects, but this was not the case in the MA subjects. The increase in adiponectin levels was significantly associated with Powerpeak. Furthermore, a significant inverse correlation was found between basal adiponectin and VO2peak and Powerpeak. In conclusion, a single bout of exhaustive exercise can rapidly and significantly enhance the basal circulating adiponectin concentration, which seems to be negatively associated with maximal aerobic capacity.

Knockout of Hsp70 genes significantly affects locomotion speed and gene expression in leg skeletal muscles of Drosophila melanogaster.

The functions of the heat shock protein 70 (Hsp70) genes were studied using a line of Drosophila melanogaster with a knockout of 6 of these genes out of 13. Namely, the effect of knockout of Hsp70 genes on negative geotaxis climbing (locomotor) speed and the ability to adapt to climbing training (0.5-1.5 h/day, 7 days/wk, 19 days) were examined. Seven- and 23-day-old Hsp70- flies demonstrated a comparable reduction (twofold) in locomotor speed and widespread changes in leg skeletal muscle transcriptome (RNA sequencing) compared with w1118 flies. To identify the functions of genes related to decreased locomotor speed, the overlapped differentially expressed genes at both time points were analyzed: the upregulated genes encoded extracellular proteins, regulators of drug metabolism, and the antioxidant response, whereas downregulated genes encoded regulators of carbohydrate metabolism and transmembrane proteins. In addition, in Hsp70- flies, activation of transcription factors related to disruption of the fibril structure and heat shock response (Hsf) was predicted, using the position weight matrix approach. In control flies, adaptation to chronic exercise training was associated mainly with gene response to a single exercise bout, whereas the predicted transcription factors were related to stress/immune (Hsf, NF-κB, etc.) and early gene response. In contrast, Hsp70- flies demonstrated no adaptation to training as well as a significantly impaired gene response to a single exercise bout. In conclusion, the knockout of Hsp70 genes not only reduced physical performance but also disrupted adaptation to chronic physical training, which is associated with changes in the leg skeletal muscle transcriptome and impaired gene response to a single exercise bout.NEW & NOTEWORTHY Knockout of six heat shock protein 70 (Hsp70) genes in Drosophila melanogaster reduced locomotion (climbing) speed that is associated with genotype-specific differences in leg skeletal muscle gene expression. Disrupted adaptation of Hsp70- flies to chronic exercise training is associated with impaired gene response to a single exercise bout.