Low-intensity Exercise Research Articles

Механізми оцінки безпечності режимів навантаження в бодібілдингу адаптаційним можливостям організму підлітків на етапі початкової підготовки

Topicality. Even at the initial training stage, the modern needs in bodybuilding, require researchers to find the most informative markers for assessing the adequacy of power loads to the adaptive reserves of the adolescent body to develop safe and efficient training models. The Aim of the Research. To determine the optimal spectrum of biochemical blood markers for assessing the adaptive and compensatory reactions of adolescents to a stressful stimulus in terms of using different intensity modes of loading at the stage of initial training in bodybuilding. Methods. The study involved 60 adolescents aged 15–16 who have been engaged in bodybuilding for a year and have no contraindications to such activities. Given the purpose of the study, the participants have been divided into three groups. Representatives of the first group used high-intensity power loads during training (Ra=0,72). Participants of the second group – the mode of power loads of average intensity (Ra=0,67). Persons of the third group – a mode of low-intensity loads (Ra=0,58). To estimate adaptation-compensatory reactions of an organism of adolescents to loading under conditions of the set modes in the course of bodybuilding, indicators of biochemical control of activity of enzymes creatine phosphokinase, lacate dehydrogenase, and concentration of cortisol in blood serum were used. Results. The obtained results indicate that in response to physical exertion under the conditions of using a high-intensity mode (Ra=0,72) in adolescents, the activity of the enzyme creatine phosphokinase increases by 46,0 % and the concentration of cortisol by 50,5 % in blood serum compared to the resting state. It was established that in response to medium-intensity loads (Ra=0,67), all controlled biochemical indicators in the blood serum increased in the range of 19,3–22,1 % compared to the initial data. The revealed biochemical results in the conditions of use by the representatives of the 3rd group in the course of the low-intensity exercise regime (Ra=0,58) show an increase in creatine phosphokinase by 3,8 %, lactate dehydrogenase by 14,4 % and a decrease in the concentration of cortisol in the blood serum by 20,4 % in response to a stimulus. Conclusions. The revealed diversity of the nature of the changes in the biochemical blood control indicators we studied demonstrates the adaptive and compensatory reactions of the adolescent body in conditions of different intensity and energy supply of muscle activity regimes of power loads in bodybuilding at the initial training stage. The obtained results will make it possible to reasonably model the optimal set of informative biochemical markers of blood, depending on the conditions of training activity and adaptation reserves of the body.

Effects of different intensity aerobic exercise on intestinal flora and gastrointestinal hormones in type 2 diabetic rats

To examine the impact and mechanisms of the aerobics exercise on gut flora and gastrointestinal hormones in type 2 diabetes rats. Methods Adult male SD rats aged 8 weeks were divided into 5 groups at random (n= 10): a peaceful comparison group (N), a diabetic comparison group (D), a diabetic low-intensity exercise group (LD), a diabetic middle-intensity exercise group (MD), and a diabetes highintensity exercise group. (HD). The rat groups LD, MD, and HD performed aerobic exercise five times per week for a total of 6 weeks and compared general condition, blood glucose, blood lipids, insulin, leptin, gastrin (GAS) and motilin ( MOT), gastrointestinal motility, and intestinal flora. Results The levels of insulin, leptin, total cholesterol, triglycerides, E. coli, LDL-cholesterol, LDL-cholesterol, insulin, and gastric residual rate were significantly different from group N. Conclusion: Type 2 diabetic rats have gut flora imbalance and gastrointestinal hormone changes. Aerobic exercise with different intensity can alleviate gastrointestinal hormone imbalance and intestinal flora imbalance in type 2 diabetes rats, and the impact of moderate intensity exercise is the strongest.

The characterization of metabolic changes in adipose tissues and muscles due to different exercise intensities by Dixon in healthy young men

PurposeTo delineate the alterations in adipose and muscle tissue composition and functionality among healthy young men across varying exercise intensities, which help to elucidate the impact of exercise intensity on weight management and inform fitness planning. Method3D Dixon MRI scans were performed on the neck and supraclavicular area in 10 high-intensity exercises (HIE) athletes, 20 moderate intensity exercises (MIE) athletes and 19 low-intensity exercises non-athlete male controls (NCM). Twelve imaging parameters, including the total volume of muscle, white adipose tissue (WAT), brown adipose tissue (BAT), and the mean fat–water fraction (FWF) within these tissues. Additionally, ratios of BAT or WAT to total fat (BATr or WATr) and the proportions of muscle, BAT, or WAT to total tissue volume (Musp, BATp, and WATp) were calculated. Parameters were compared across groups and correlated with Body Mass Index (BMI), waistline, and hipline. ResultsThe HIE group exhibited the highest total muscle (totalMUS) and brown adipose tissue (totalBAT) volumes among the three groups. Conversely, the NCM group had significantly higher fwfFAT and fwfBAT values. The MUSp was higher in the HIE and MIE groups compared to NCM, while the BATp and WATp were lower. Furthermore, the BATr in HIE and MIE groups were higher than NCM group while the WATr were lower. Significant linear relationships were observed between totalBAT, totalWAT, MUSp, BATr, fwfFAT, and BMI, waistline (P < 0.05) across all groups. ConclusionsMIE is sufficient for the purpose of weight control, While HIE helps to further increase the muscle mass. All three physical indexes were significantly associated with the image parameters, with waistline emerging as the most effective indicator for detecting metabolic changes across all groups.

A mini-review on influence of physical exercise in remodeling the immune mechanism

Exercising on a regular basis has been associated with delay in onset of many lifestyle disorders and chronic conditions. Different types of exercise have varied effects on our innate immune cells, both positively and negatively. Low-intensity exercises like yoga or brisk walking, medium-intensity exercises like swimming or cycling, and long-term high-intensity exercises like playing sports like volleyball or working out in the gym are some examples. The immune system's function is impacted differently by exercise training depending on the type, duration, intensity, and other factors. Exercise training is a double-edged sword that helps the body's immune system by changing the immune cells' post-exercise reaction mechanisms. Regular physical exercise is one of the lifestyle adjustments aimed at minimizing morbidity and mortality associated with contemporary illnesses such as obesity, diabetes, cardiovascular disease, and cancer. Regular leisure exercise training is regarded to be beneficial, but extreme exercise, such as that performed by professional athletes, is thought to have possibly detrimental consequences. This review summarizes current information in the field of exercise-associated alterations of infection susceptibility and indicates knowledge gaps for further investigation. It highlights that long term effects of physical activity shows a positive association with longevity and exercise.

Effects of different exercise modes and intensities on cognitive performance, adult hippocampal neurogenesis, and synaptic plasticity in mice.

Exercise can induce beneficial improvements in cognition. However, the effects of different modes and intensities of exercise have yet to be explored in detail. This study aimed to identify the effects of different exercise modes (aerobic and resistance) and intensities (low and high) on cognitive performance, adult hippocampal neurogenesis and synaptic plasticity in mice. A total of 40 C57BL/6J mice were randomised into 5 groups (n = 8 mice per group): control, low-intensity aerobic exercise, high-intensity aerobic exercise, low-intensity resistance exercise, and high-intensity resistance exercise. The aerobic exercise groups underwent treadmill training, while the resistance exercise groups underwent ladder climbing training. At the end of the exercise period, cognitive performance was assessed by the Y-maze and Barnes maze. In addition, adult hippocampal neurogenesis was evaluated immunohistochemically by 5-bromo-2'-deoxyuridine (BrdU)/ neuronal nuclei (NeuN) co-labeling. The levels of synaptic plasticity-related proteins in the hippocampus, including synaptophysin (SYP) and postsynaptic density protein 95 (PSD-95), were analyzed by western blotting. Our results showed no significant differences in cognitive performance among the groups. However, high-intensity aerobic exercise significantly increased hippocampal adult neurogenesis relative to the control. A trend towards increased adult neurogenesis was observed in the low-intensity aerobic group compared to the control group. No significant changes in synaptic plasticity were observed among all groups. Our results indicate that high-intensity aerobic exercise may be the most potent stimulator of adult hippocampal neurogenesis.

#899 The effect of exercise training on microRNAs in patients undergoing hemodialysis

Abstract Background and Aims Physical inactivity is a risk factor for mortality and morbidity in patients undergoing hemodialysis (HD). Therefore, physical exercise (PE) is recommended as part of the management of HD patients. Although the benefits of PE for HD patients have been well documented in the literature, the pathophysiological mechanism still needs to be fully understood. Recently, microRNAs (miRNAs) have come to light as potential mediators of PE's therapeutic effects in healthy individuals. Currently, no information is available about how PE affects the expression of miRNAs in HD patients, mainly for osteogenic differentiation, a critical process in forming vascular calcification. Therefore, this observational longitudinal study aims to assess the expression of miR-9 and miR-30b, two regulators of the osteogenic commitment from endothelial progenitor cells, in HD patients engaged in an interdialytic exercise program. Method Male HD patients aged between 50 and 80 could walk for at least six meters were enrolled. Exclusion criteria were uncorrected anemia, acute infectious disease, uncontrolled hyperparathyroidism, active oncologic disease, and severe cardio-respiratory, musculoskeletal, or neurological conditions inhibiting exercise training. Patients were engaged in a structured interdialytic program supervised by an exercise facilitator. Exercise training was performed at home or the dialysis centre based on the patient's needs and preferences. It consisted of a 10-minute session/day of low-intensity walking and/or resistance exercises. The speed was increased weekly and controlled with a metronome application on the patient's smartphone. The maximum distance covered evaluates the patients' physical performance, as measured by the 6-minute walking test (6MWT). It was assessed at baseline and the 6-month follow-up. Blood samples for miRNA analysis were collected during the short interdialytic period at baseline and at the 6-month follow-up. MiRNAs will be extracted from serum samples using the miRNeasy Serum/Plasma Advanced Kit. Statistical analysis will be performed using SPSS 21.0. The difference between the two groups was assessed using a t-test for paired data. P-values&amp;lt;0.05 were considered statistically significant. Results Patients’ characteristics at baseline are shown in Table 1. Five patients were enrolled in the study, three undergoing exercise training at the dialysis centre and two at home. At six months, miR-30b expression appeared significantly upregulated in all patients (p&amp;lt;0.03) (Fig. 1). At the same time, the upregulation of miR-9 did not reach significance (p = 0.07). In one patient, miR-9 was not detected (Fig. 2). The mean distance covered during the 6MWT did not improve at six months (255 ± 129 meters) compared to baseline (235 ± 118 meters) (p = 0.49). Conclusion Preliminary results of this longitudinal observational study show that miR-30b was upregulated in patients engaged in the exercise training period at the 6-month follow-up despite no improvement in physical performance. The upregulation of miR-30b levels can potentially reduce the dedifferentiation of vascular smooth muscle cells into an osteoblastic-like phenotype. At the end of our study, novel evidence concerning the potential effect of exercise training on miRNA expressions correlated to the vascular calcification process in HD patients will be available.

10 weeks low intensity treadmill exercise intervention ameliorates motor deficits and sustains muscle mass via decreasing oxidative damage and increasing mitochondria function in a rat model of Parkinson's disease

AimsParkinson's disease (PD) is characterized by loss of dopamine neurons in the brain, which leads to motor dysfunction; excessive inflammation induces neuronal death. This study aimed to determine the most effective exercise modality to improve motor dysfunction in PD by comparing three different exercise regimens (low-intensity treadmill, high-intensity treadmill, and swimming). Materials and methodsThe rat model for PD was established through stereotaxic surgery, inducing unilateral 6-OHDA (6-hydroxydopamine) lesions. The low-intensity treadmill regimen exerted better protective effects on neurological and motor functions in a rat model of unilateral 6-OHDA-induced PD compared to high-intensity treadmill and swimming. The most suitable exercise regimen and the optimal duration of daily exercise (15 or 30 min) on motor activity and oxidative stress parameters were evaluated. Key findingsComparison of 15 and 30 min low-intensity treadmill regimens (10 m/min) revealed 30 min daily exercise was the optimal duration and had more favorable impacts on neurological and motor function. Furthermore, we assessed the neuroprotective effects of exercising for 15 and 30 min per day for either four or ten weeks; 30 min of daily exercise for ten weeks improved mitochondrial function, the antioxidant defense system, neurotrophic factors, and muscle mass, and thereby provided protection against dopaminergic neuron loss, and motor dysfunction in rats with 6-OHDA-induced PD. Significance30 min of daily low-intensity treadmill exercise over 10 weeks resulted in heightened mitochondrial function in both muscle and brain tissues, therefore, yielded a neuroprotective effect against the loss of dopaminergic neurons and motor dysfunction in PD rats.

Cardiac diastolic maladaptation is associated with the severity of exercise intolerance in sickle cell anemia patients

This pilot study focusing on Sickle Cell Anemia (SCA) patients offers a comprehensive and integrative evaluation of respiratory, cardiovascular, hemodynamic, and metabolic variables during exercise. Knowing that diastolic dysfunction is frequent in this population, we hypothesize that a lack of cardiac adaptation through exercise might lead to premature increase in blood lactate concentrations in SCA patients, a potential trigger for acute disease complication. SCA patients were prospectively included in PHYSIO-EXDRE study and underwent a comprehensive stress test with a standardized incremental exercise protocol up to 4 mmol L−1 blood lactate concentration (BL4). Gas exchange, capillary lactate concentration and echocardiography were performed at baseline, during stress test (at ∼ 2 mmol L−1) and BL4. The population was divided into two groups and compared according to the median value of percentage of theoretical peak oxygen uptake (%V˙O2peakth\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}\ ext{O}}_{2peakth}$$\\end{document}) at BL4. Twenty-nine patients were included (42 ± 12 years old, 48% of women). Most patients reached BL4 at low-intensity exercise [median value of predicted power output (W) was 37%], which corresponds to daily life activities. The median value of %V˙O2peakth\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\dot{\ ext{V}}\ ext{O}}_{2peakth}$$\\end{document} at BL4 was 39%. Interestingly, diastolic maladaptation using echocardiography during stress test along with hemoglobin concentration were independently associated to early occurrence of BL4. As BL4 occurs for low-intensity exercises, SCA patients may be subject to acidosis-related complications even during their daily life activities. Beyond assessing physical capacities, our study underlines that diastolic maladaptation during exercise is associated with an early increase in blood lactate concentration.

Aerobic exercise training engages the canonical wnt pathway to improve pulmonary function and inflammation in COPD

BackgroundWe studied whether the exercise improves cigarette smoke (CS) induced chronic obstructive pulmonary disease (COPD) in mice through inhibition of inflammation mediated by Wnt/β-catenin-peroxisome proliferator-activated receptor (PPAR) γ signaling.MethodsFirstly, we observed the effect of exercise on pulmonary inflammation, lung function, and Wnt/β-catenin-PPARγ. A total of 30 male C57BL/6J mice were divided into the control group (CG), smoke group (SG), low-intensity exercise group (LEG), moderate-intensity exercise group (MEG), and high-intensity exercise group (HEG). All the groups, except for CG, underwent whole-body progressive exposure to CS for 25 weeks. Then, we assessed the maximal exercise capacity of mice from the LEG, MEG, and HEG, and performed an 8-week treadmill exercise intervention. Then, we used LiCl (Wnt/β-catenin agonist) and XAV939 (Wnt/β-catenin antagonist) to investigate whether Wnt/β-catenin-PPARγ pathway played a role in the improvement of COPD via exercise. Male C57BL/6J mice were randomly divided into six groups (n = 6 per group): CG, SG, LiCl group, LiCl and exercise group, XAV939 group, and XAV939 and exercise group. Mice except those in the CG were exposed to CS, and those in the exercise groups were subjected to moderate-intensity exercise training. All the mice were subjected to lung function test, lung histological assessment, and analysis of inflammatory markers in the bronchoalveolar lavage fluid, as well as detection of Wnt1, β-catenin and PPARγ proteins in the lung tissue.ResultsExercise of various intensities alleviated lung structural changes, pulmonary function and inflammation in COPD, with moderate-intensity exercise exhibiting significant and comprehensive effects on the alleviation of pulmonary inflammation and improvement of lung function. Low-, moderate-, and high-intensity exercise decreased β-catenin levels and increased those of PPARγ significantly, and only moderate-intensity exercise reduced the level of Wnt1 protein. Moderate-intensity exercise relieved the inflammation aggravated by Wnt agonist. Wnt antagonist combined with moderate-intensity exercise increased the levels of PPARγ, which may explain the highest improvement of pulmonary function observed in this group.ConclusionsExercise effectively decreases COPD pulmonary inflammation and improves pulmonary function. The beneficial role of exercise may be exerted through Wnt/β-catenin-PPARγ pathway.

Sheng Zhen Gong in pregnancy: The effects of a traditional low intensity exercise form on maternofetal health and wellbeing

Objective: The aim of the study was to evaluate maternal and fetal responses to Sheng Zhen Gong (SZG), a low intensity form of exercise, using multi-modal antenatal surveillance techniques. Methods: This was a single-blinded randomized controlled trial in low risk pregnant women from a tertiary center in the Philippines. Participants were randomized into Chronic Exercise (CE), Acute Exercise (AE) and No Exercise (NE) groups. A Pregnancy Physical Activity Questionnaire (PPAQ) was given to ascertain baseline activities. Systematic periodic assessment was performed utilizing standard ultrasound and Doppler studies between 20+0 to 32+0 weeks gestation with or without sessions involving a biophysical and Warwick-Edinburgh Mental Well-being Scale (WEMWBS) evaluation before and after SZG exercise. Results: Eighty-nine (89) women were included with average energy expenditures of light to moderate intensity. In the CE group, systolic, diastolic, mean arterial pressures and heart rates were lower while oxygen saturations increased after exercise (n=35; p: &lt;0.01 to 0.01). There were also observable significant increases in maternal well-being scores after exercise for both CE (n=35) and AE (n=21) groups (p&lt;0.01). Increasing the frequency of exercise was also associated with better maternal well-being (p: 0.02). Fetal Doppler studies showed no significant changes after exercise. Conclusion: In normal pregnancy, routine low intensity physical activity in the form of SZG was seen to have positive effects on maternal cardiovascular, blood glucose and mental well-being maintenance with no evidence of detrimental effects on the fetus.

A canine model to evaluate the effect of exercise intensity and duration on olfactory detection limits: the running nose.

Detection canines serve critical roles to support the military, homeland security and border protection. Some explosive detection tasks are physically demanding for dogs, and prior research suggests this can lead to a reduction in olfactory detection sensitivity. To further evaluate the effect of exercise intensity on olfactory sensitivity, we developed a novel olfactory paradigm that allowed us to measure olfactory detection thresholds while dogs exercised on a treadmill at two different exercise intensities. Dogs (n = 3) showed a decrement in olfactory detection for 1-bromooctane at 10-3 (v/v) dilutions and lower under greater exercise intensity. Dogs' hit rate for the lowest concentration dropped from 0.87 ± 0.04 when walking at low intensity to below 0.45 ± 0.06 when trotting at moderate intensity. This decline had an interaction with the duration of the session in moderate intensity exercise, whereby dogs performed near 100% detection in the first 10 min of the 8 km/h session, but showed 0% detection after 20 min. Hit rates for high odor concentrations (10-2) were relatively stable at both low (1 ± 0.00) and moderate (0.91 ± 0.04) exercise intensities. The paradigm and apparatus developed here may be useful to help further understand causes of operationally relevant olfactory detection threshold decline in dogs.

The influence of low back pain-related attitudes and beliefs on the clinical decision making of physical therapists

ABSTRACT Background The LBP-related attitudes and beliefs of clinicians may impact the experience of patients by influencing clinician decision-making and by shaping the attitudes, beliefs, and actions of patients. The purpose of this study was to identify the specific LBP-related attitudes and beliefs of US-based physical therapists and determine if those beliefs correlate with clinical decision-making. Methods An electronic survey was sent to US-based physical therapists. Attitudes and beliefs were measured using the Health Care Providers’ Pain and Impairment Relationship Scale (HC-PAIRS) and the Pain and Impairment Relationship Scale for Physiotherapists (PABS-PT). The survey also included 2 patient vignettes that collected information about clinical decision-making. Results Complete survey responses were recorded from 420 physical therapists. Eleven of the 27 attitude and beliefs questions were answered in a more biomedically oriented way by at least 20% of respondents. Physical therapist low back pain-related attitudes and beliefs were associated with activity and management strategies for both vignettes in the expected direction. Higher scores on HC-PAIRS and PABS-BM were associated with more restrictive work and activity recommendations, lower-intensity exercise choices, biomechanical rationale for manual therapy and motor control exercises, pathoanatomical-focused education, and use of modalities. Conclusion Some physical therapists hold biomedically oriented beliefs about the connection between pain and physical activity. Clinician beliefs were associated with activity and work recommendations, and treatment choices. Physical therapists with more biomedically oriented beliefs were more likely to limit physical activity and work, and less likely to incorporate psychologically informed interventions.

EXERCISE TRAINING IMPROVES GASTROINTESTINAL SYMPTOMS IN PEOPLE WITH A DISORDER OF THE GUT BRAIN INTERACTION (DGBI): SYSTEMIC REVIEW AND META-ANALYSIS

INTRODUCTION &amp; AIMS Approximately 40% of the global population has criteria that meets at least one Disorder of the Gut-Brain Interaction (DGBI). DGBIs are characterised by the absence of structural abnormalities, with chronic symptoms, such as pain, altered bowel movements, and nausea. Current therapy options focus on treating the major symptoms, which can involve pharmacological and lifestyle advice (diet, exercise, and stress management). The aim of this study was to conduct a systematic review and meta-analysis investigating the efficacy of exercise for improving gastrointestinal symptoms in people with a DGBI. METHODS A search of relevant databases was completed in February 2023, for randomised controlled trials that applied an exercise intervention in people with DGBI. Comparator groups included usual care, pharmacological therapy, or diet advice. A pairwise random-effects meta-analysis estimated the standardised mean difference (SMD) (Hedges’ g) between exercise and comparator groups for changes in gastrointestinal symptoms. Risk of bias was analysed using the Cochrane Risk of Bias tool. RESULTS Ten studies published between 2004–2023 were included. Participants (n=653) were mostly female 77.6%. Eight studies included participants with irritable bowel syndrome and two included individuals with functional dyspepsia. Exercise interventions lasted an average duration of 8 weeks. The modes included yoga (n=5), low intensity (n=1) and moderate intensity aerobic exercise (n=4). Studies ranged from low to high-risk bias. Meta-analysis showed exercise interventions improved gastrointestinal symptoms (SMD=1.2, 95% CI 0.5 to 1.8; p&amp;lt;0.001). The effect was moderated by the intensity of exercise with moderate intensity aerobic exercise having a significant impact (SMD=1.6, 1.2 to 2.0; p&amp;lt;0.001) not evident with yoga and low intensity exercise interventions (SMD=0.9, -0.01 to 1.7; p=0.053). CONCLUSION Exercise interventions in people with DGBIs improve gastrointestinal symptoms. Moderate intensity aerobic exercise is more efficacious than yoga and lower intensity exercise.

Exercise Intensity Assessment of Care Farming Activities in Adults

We aimed to determine the energy expenditure, oxygen uptake, and exercise intensity of 10 care farming activities performed by adults. The study had a crossover experimental design. Participants performed 10 care farming activities for 5 minutes, including four plant- and three animal-mediated activities, and three other activities. Each participant wore a portable telemetric calorimeter during the activities, and oxygen uptake, heart rate, and exercise intensity were measured. Twenty-one adults (aged 31.5 ± 10.2 years) participated in our study. Energy expenditure, oxygen uptake, and exercise intensity differed significantly for each activity. The 10 care farming activities were regarded as light- to moderate-intensity activities. The exercise intensity, energy expenditure, and oxygen uptake for organizing a garden plot were significantly higher than those for other care farming activities. Cooking using harvests, interacting with dogs, and feeding rabbits had the lowest exercise intensity, energy expenditure, and oxygen uptake. Other activities, such as transplanting plants, harvesting, creating art, maintaining a garden, walking with a dog, and cleaning the farm, had moderate exercise intensity, energy expenditure, and oxygen uptake. Energy expenditure, oxygen uptake, and exercise intensity data could be useful when developing a care farming program suitable for the physical condition of participants in care farming interventions.

The role of the cardiac vagus in maintaining cardiac function during exercise

There is a strong association between parasympathetic nervous system activity (vagal tone) and physical fitness. High vagal tone is associated with increased capacity to exercise and overall cardiovascular health. Evidence for vagal withdrawal during exercise comes from historic studies examining heart rate control and the use of cholinergic blockers. However, more recent studies have challenged this assumption. We hypothesized that cardiac vagal activity increases during exercise and maintains cardiac function via neurotransmitters other than acetylcholine. The left cardiac vagal branch was identified in anesthetized open-chested sheep. Cardiac innervation of the left cardiac vagal branch was confirmed with lipophilic tracer dyes (DiO). Custom-built coil electrodes were placed around the left cardiac vagal branch. 3-10 days after surgery, conscious, direct recordings of cardiac vagal nerve activity (CVNA), cardiac output, coronary artery blood flow and heart rate were recorded in adult female sheep during whole-body treadmill exercise. Sheep were exercised with pharmacological blockers of acetylcholine (atropine, 250 mg), vasoactive intestinal peptide (VIP) ([4Cl−D-Phe6,Leu17]-VIP 25 μg), or saline control, randomized on different days. In a subset of sheep, the left cardiac vagal branch was denervated. Neural innervation from the cardiac vagal branch is seen at major cardiac ganglionic plexi, and within the fat pads associated with the coronary arteries. Directly recorded CVNA increased during exercise. CVNA increases during the lowest exercise intensity and plateaus as exercise intensity increases. Left cardiac vagal branch, denervation attenuated the maximum changes in coronary artery blood flow (maximum exercise, control: 63.5 ± 5.9 ml/min, n = 8, cardiac vagal denervated: 32.7 ± 5.6 ml/min, n = 6, mean ± SEM. P = 2.5x10−7. Two-way ANOVA-interaction), cardiac output and heart rate during exercise. Atropine did not affect any cardiac parameters during exercise, but VIP antagonism significantly reduced coronary artery blood flow during exercise to a similar level to vagal denervation (maximum exercise, paired: control: 68.2 ± 6.0 ml/min, VIP antagonism: 44.9 ± 3.9 ml/min, n = 6, mean ± SEM. P = 4.8x10−3. Two-way ANOVA-interaction). Our study challenges the conventional view and demonstrates that cardiac vagal nerve activity increases and is crucial for maintaining cardiac function during exercise. Furthermore, our findings show that the dynamic modulation of coronary artery blood flow during exercise is mediated by VIP and that acetylcholine has no role in modulating cardiac function during exercise. This work is supported by the Health Research Council of New Zealand 23/119 (Fellowship. JS) and the New Zealand Heart Foundation (JS, RR). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Postmenopausal Women with Obesity have Reduced Leg Endothelial Function and Exercise Vasodilatory Capacity

Background: Obesity (OB) is highly prevalent in postmenopausal women; particularly increased abdominal visceral adipose tissue contributes to endothelial dysfunction and cardiovascular risk. The endothelium plays an important role on blood flow (BF) and pressure control at rest and during exercise. However, it is unknown how different body mass index (BMI) categories influence upper and lower limb endothelial function and BF responses to exercise in postmenopausal women. Purpose: The purpose was to examine upper and lower limb endothelial function at rest and BF regulation during low-intensity exercises in OB, overweight (OW), and lean (LN) postmenopausal women. We hypothesized that endothelial function and BF responses to submaximal exercise in both limbs will be attenuated in OB compared to the OW and LN groups. Methods: Women were classified as OB (30.0-39.9 kg/m2; n = 13), OW (25.0-29.9 kg/m2; n = 15), and LN (18.5-24.9 kg/m2; n = 11) by BMI. Flow-mediated dilation (FMD) of the brachial (BA-FMD) and superficial femoral arteries (FA-FMD) were measured using ultrasound. BF and vascular conductance (VC) in the brachial (BA-BF and BA-VC) and femoral (FA-BF and FA-VC) arteries were measured during separate 3-stage incremental rhythmic handgrip and plantarflexion exercises (PFE) at 5, 15, and 30 % of maximal strength and calculated 1-repetition max (1RM), respectively. Results: No differences in BA-FMD were observed among the groups. FA-FMD was significantly lower in OB (2.6 ± 1.4%) compared to OW (4.3 ± 1.9%) and LN (4.2 ± 0.7%) groups (P &lt; 0.05). Increases in FA-BF (OB: 462 ± 229 vs. OW: 616 ± 173 vs. LN: 640 ± 141 mL/min; P &lt; 0.001) and FA-VC (OB: 410 ± 176 vs. OW: 585 ± 155 vs LN: 623 ± 153 mL/min*100mmHg; P &lt; 0.001) were attenuated during PFE at 30% of 1RM in OB compared to OW and LN. Upper-body exercise vasodilation was not attenuated by OB. FA-BF and FA-VC during PFE at 30% of 1RM were correlated with FA-FMD (FA-BF: r = 0.423, P = 0.007, FA-VC: r = 0.367, P = 0.021) and BMI (FA-BF: r = -.386, P = 0.015, FA-VC: r = -.456, P = 0.004). Conclusion: Postmenopausal women with OB have blunted leg endothelial function and exercise vasodilator function during submaximal dynamic plantarflexion exercise compared to LN and OW. These findings suggest that OB may contribute to reduce leg endothelial function, and vasodilator function during exercise in postmenopausal women. No support of funding information to disclose. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

THE ACUTE EXERCISE-INDUCED INFLAMMATORY RESPONSES IN GASTROINTESTINAL DISORDERS

INTRODUCTION &amp; AIMS Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), are characterised by intestinal inflammation that presents severe symptoms and continued complications throughout the lifespan. These gastrointestinal (GI) disorders have a growing prevalence worldwide with no known cure. Management strategies often require a ‘trial and error’ process before an effective pharmacal/s is established; the successful interim varies considerably with prevalent adverse side-effects and gradual decline in the effectiveness of medication. Accordingly, alternative mechanisms to complement management options, reduce side-effects, and improve well-being warrant investigation. Physical activity is known to be beneficial for a variety of inflammatory conditions; the advantageous effects are associated with the exercise-induced inflammatory response directly from active muscle tissue. Despite this knowledge, minimal studies have attempted to quantify the inflammatory effect of exercise. This study investigates the inflammatory response of acute exercise. METHODS Participants were allocated into one of two groups: GI disorders (IBD &amp; IBS; n = 11) or apparently healthy control (AHC; n = 11). All participants completed three sessions: 1) initial familiarisation: questionnaires, anthropometry measures, DEXA scan, and a graded exercise test; 2) protocol 1: moderate-intensity continuous exercise; and 3) protocol 2: alternating high- and low-intensity exercise. Participants were randomly allocated to the acute exercise protocols. Each protocol had a fasted pre-exercise venous blood sample, 35-minutes cycle, fasted blood sample immediately post-, 2hrs post-, and 24hr post-exercise. RESULTS Significant differences were observed between groups in body mass index, waist and hip circumstances, percentage of fat mass, and VO2peak (p &amp;lt; .05). Analyses of venous blood samples will be presented. CONCLUSION With no known cure, lifestyle management is important for those with GI disorders. Exercise hosts several benefits; however, given the inflammatory nature of the condition, the acute responses of exercise are important for clinicians working with IBD/IBS patients.

PAINFUL VS NON-PAINFUL EXERCISE ON CREPITUS IN PEOPLE WITH KNEE OSTEOARTHRITIS: A MIXED-METHODS ANALYSIS

INTRODUCTION &amp; AIMS Crepitus (or physiological noise) is a key criterion in the diagnosis of knee osteoarthritis (OA). Exercise is foundational to guideline-based care for knee OA, however the effect exercise on knee crepitus is unknown. This study aimed to explore the perceptions of people with knee OA following a 6-week accredited exercise physiologist (AEP) led intervention involving painful vs non-painful exercise, especially in relation to their knee crepitus. METHODS Participants were randomly assigned to either a painful (higher intensity) or non-painful (lower intensity) exercise program supervised by an AEP twice a week for six weeks with concurrent education. Volunteers partook in a post-intervention semi-structured interview with questions surrounding their experience and perceived outcomes of the program. Thematic qualitative analysis was conducted and compared to the Knee Injury and Osteoarthritis Outcome Score (KOOS) crepitus question (0 - 4 scale). RESULTS Eleven participants volunteered. Qualitatively, approximately half of the participants self-reported a decrease in their knee crepitus following the program “I haven’t had the creaky knees so much”, with the rest stating their crepitus did not change. No participants perceived their crepitus increased (n=9 no change, n=2 decreased) or said that their crepitus was worse, “the noise and grinding doesn’t become evident (now) until the weights become higher”. Quantitatively, KOOS crepitus scores also did not change following the intervention [mean (SD) (2.4(1.0) to 2.1(1.3), p=0.19)]. There were no differences between exercise groups in self-perceived crepitus results, and most said that the exercise program was beneficial “Right after this whole program, I find that I can move much easier.” CONCLUSION Exercise at higher intensities (into painful range) does not change crepitus or may improve it for some. People with OA perceive that exercise at both higher and lower intensity is beneficial and enjoyable.

Resposta Hipertensiva ao Exercício: uma Forma de Apresentação da Hipertensão Mascarada

Blood pressure measurements outside the office allowed the identification of two opposing phenotypes, commonly known as white coat hypertension and masked hypertension (MH). Whether the hypertensive response to exertion, also called exaggerated blood pressure response to exercise, represents a marker of MH in individuals without a previous history of hypertension is not yet clear, but several follow-up studies have indicated that this finding is associated with the highest future incidence of arterial hypertension, heart failure with preserved ejection fraction and cardiovascular events. Based on data from several studies, the most used definition for hypertensive response to exertion is 210/100 mmHg for men, 190/100 mmHg for women and 220/85mmHg for male athletes and 200/80 mmHg for female athletes. Measuring BP during a low-intensity exercise session (Bruce stage I/II or 70% of maximum theoretical heart rate) also seems to define increased cardiovascular risk, with good accuracy (values &gt;170 mmHg). When the BP values during exercise exceed normal limits, it should be suspected MH and recommended a subsequent study to revaluate BP at home and ABPM, as well as study the cardiorenal repercussion.

Physical activity, exercise habits and health-related quality of life in maintenance hemodialysis patients: a multicenter cross-sectional study

BackgroundAlthough exercise has the potential to yield numerous benefits for maintenance hemodialysis patients, the relationship between physical activity, exercise habits, and health-related quality of life (HRQOL) has not been thoroughly investigated. This study aimed to characterize the physical activity, exercise habits, and HRQOL of maintenance hemodialysis patients while examining the associations between these factors.MethodsA convenience sampling was used to recruit 827 patients from 74 dialysis units in China. The structured questionnaire included sociodemographics, the International Physical Activity Questionnaire, exercise habits, and the Kidney Disease Quality of Life Short Form 1.3. An independent samples t-test, multivariable logistic regression analysis, and multivariable linear regression analysis were used.ResultsThe physical activity levels of 69% of participants were found to be below the recommendation of the World Health Organization. Despite 62.4% of participants reporting regular exercise, 73.8% reported light exercise intensity, and 92.6% engaged in walking or jogging. Participants’ HRQOL was higher in the low-intensity exercise group compared with the moderate-to-hard-intensity exercise group. Moderate-to-high physical activity was associated with better HRQOL in 13 of the 19 domains and regular exercise was linked to higher HRQOL in four of the 19 domains.ConclusionsThis study identified a low level of physical activity, light exercise intensity, and walking as the primary exercise type among the participants. A significant correlation was found between higher physical activity levels, regular exercise, and better HRQOL for maintenance hemodialysis patients. It is advisable to implement strategies to enhance physical activity levels and design exercise programs for maintenance hemodialysis patients based on their real-world physical activity levels and exercise habits.Graphical abstract