Different Levels Of Exercise Research Articles

Causal Associations Between Lifestyle Habits and Risk of Benign Prostatic Hyperplasia: A Two-Sample Mendelian Randomization Study.

Benign prostatic hyperplasia (BPH) most often occurs in older men; previous studies and clinical experience suggest a potential link between lifestyle habits such as sleep habits, sedentary behavior, exercise levels, and BPH, but whether they have a clear causal relationship and the direction of that causality is unclear. We aimed to investigate the causal relationship between lifestyle habits and BPH using 2-sample Mendelian randomization (MR) analysis. Instrumental genetic independent variables strongly associated with the selected exposure factors were filtered from published genome-wide association studies (GWAS) consisting primarily of European ancestry samples. GWAS from BPH was analyzed as an MR outcome with the inverse-variance weighted method, maximum likelihood, weighted median method, MR-Egger regression, and several sensitivity analyses, including Cochran's Q test, intercept of MR-Egger, and MR pleiotropy residual sum and outlier test. MR analysis showed a significant causal risk relationship between sleep duration and BPH, with an odds ratio of 0.42 (95% confidence interval, 0.25-0.69, p = .001) for BPH when sleep duration was increased by 1 standard deviation, but we did not find a causal relationship between the 2 when we performed a reverse analysis. However, sedentary behavior and different levels of exercise did not significantly affect the risk of BPH. This study showed a strong causal relationship between sleep levels and BPH, with adequate sleep duration being a protective factor for BPH.

Cardiac Mechanical Performance Assessment at Different Levels of Exercise in Childhood Acute Lymphoblastic Leukemia Survivors.

There is a shortage of relevant studies interested in cardiac mechanical performance. Thus, it is clinically relevant to study the impact of cancer treatments on survivors' cardiac mechanical performance to improve our knowledge. The first objective of this study is to assess survivors' cardiac mechanical performance during a cardiopulmonary exercise test (CPET) using both ventricular-arterial coupling (VAC) and cardiac work efficiency (CWE) from cardiac magnetic resonance (CMR) acquisitions. The second objective is to assess the impact of doxorubicin and dexrazoxane (DEX) treatments. A total of 63 childhood acute lymphoblastic leukemia survivors underwent a CMR at rest on a 3T magnetic resonance imaging system, followed by a CPET on ergocycle. The CircAdapt model was used to study cardiac mechanical performance. At different levels of exercise, arterial elastance, end-systolic elastance, VAC, and CWE were estimated. We observed significant differences between the different levels of exercise for both VAC ( P <0.0001) and CWE parameters ( P =0.001). No significant differences were reported between prognostic risk groups at rest and during the CPET. Nevertheless, we observed that survivors in the SR group had a VAC value slightly lower than heart rate (HR)+DEX and HR groups throughout the CPET. Moreover, survivors in the SR group had a CWE parameter slightly higher than HR+DEX and HR groups throughout the CPET. This study reveals that the combination of CPET, CMR acquisitions and CircAdapt model was sensitive enough to observe slight changes in the assessment of VAC and CWE parameters. Our study contributes to improving survivors' follow-up and detection of cardiac problems induced by doxorubicin-related cardiotoxicity.

The effects of exercise on the quality of life of patients with breast cancer: a systematic review and meta-analysis based on the QLQ-C30 quality of life scale.

Studies have reported that exercise can effectively improve the quality of life of breast cancer (BC) patients. However, considering the differences in exercise form and intensity, it is difficult to quantify and unify the improved outcomes, and there are contradictions in the conclusions. This meta-analysis aimed to quantitatively evaluate the effects of exercise on the quality of life (QoL) of patients with BC based on the European Organization for Research and Treatment of Cancer QoL Questionnaire-C30 (QLQ-C30) scale, to provide optimization suggestions for the treatment plan of BC survivors. The literature were extracted from the databases of PubMed, Embase, Cochrane Library, Wanfang, and China National Knowledge Infrastructure. The main outcomes were extracted from the final included literature and chi square tests and I2 statistics were used to evaluate the heterogeneity among the included studies. Statistical analysis was performed by Stata/SE 16.0 software and Review Manager 5.4 software. The funnel plot was used to test for evaluation publication bias. All 8 included articles were original studies. The risk bias evaluation showed that 2 articles had low risk of bias and 6 articles had uncertain risk of bias. The results of meta-analysis revealed the following: (I) exercise significantly improved the overall health status of BC patients [mean difference (Hedges's g) =0.81, 95% confidence interval (CI): 0.27, 1.34]; (II) exercise significantly improved the physiological function of patients (Hedges's g =0.78, 95% CI: 0.34, 1.22), daily life function (Hedges's g =0.45, 95% CI: 0.13, 0.77), emotional function (Hedges's g =0.52, 95% CI: 0.20, 0.84); (III) exercise significantly reduced the fatigue symptoms (Hedges's g =-0.51, 95% CI: -0.84, -0.19), nausea and vomiting symptoms (Hedges's g =-0.35, 95% CI: -0.60, -0.10), insomnia symptoms (Hedges's g =-0.59, 95% CI: -0.91, -0.26), and economic difficulties (Hedges's g =-0.48, 95% CI: -0.78, -0.18) of patients. Exercise can significantly improve the overall physical health and body functions of BC survivors. Exercise can also significantly reduce the symptoms of fatigue, nausea, vomiting, and insomnia in BC patients. Different levels of exercise have significant effects on improving the quality of life of BC survivors, which is worth being widely advocated.

Chest-scale self-compensated epidermal electronics for standard 6-precordial-lead ECG

Six chest leads are the standardized clinical devices of diagnosing cardiac diseases. Emerging epidermal electronics technology shift the dangling wires and bulky devices to imperceptible wearing, achieving both comfortable experience and high-fidelity measuring. Extending small areas of current epidermal electronics to the chest scale requires eliminating interference from long epidermal interconnects and rendering the data acquisition (DAQ) portable. Herein, we developed a chest-scale epidermal electronic system (EES) for standard precordial-lead ECG and hydration monitoring, including the only μm-thick substrate-free epidermal sensing module and the soft wireless DAQ module. An electrical compensation strategy using double channels within the DAQ module and epidermal compensated branches (ECB) is proposed to eliminate unwanted signals from the long epidermal interconnects and to achieve the desired ECG. In this way, the EES works stably and precisely under different levels of exercise. Patients with sinus arrhythmias have been tested, demonstrating the prospect of EES in cardiac diseases.

Stroke survivors with the same levels of exercise as healthy individuals have lower levels of physical activity.

Physical activity and exercise are different constructs. However, professionals usually employ heterogeneous definitions for these distinct constructs, resulting in nonspecific and inaccurate assessments, which compromise clinical decision making. The aim of this study was to verify if the levels of physical activity behave similarly between individuals with stroke and healthy-control individuals with the same levels of exercise. Seventy-five stroke survivors and 75 healthy-control individuals matched by levels of exercise, age, and sex were evaluated. The level of exercise was classified as inactive, insufficient, and moderate/vigorous according to the Centers for Disease Control and Prevention criteria. The level of physical activity was assessed with the Human Activity Profile (HAP) and classified as "inactive," "moderately active," and "active." The physical activity level was compared between groups of subjects (stroke versus healthy-control) and subgroups of the level of exercise ("inactive," "insufficient," and "moderate/vigorous" level of exercise) (α = 5%). Stroke survivors had a significantly lower level of physical activity (HAP: 51 ± 22 and 71 ± 19 points, respectively). Only for individuals with stroke, a statistically significant difference was found in the levels of physical activity between subgroups of level of exercise, specifically between "inactive" and "moderate/vigorous" subgroups (HAP:47 ± 22 and 70 ± 8 points, respectively). Physical activity behaved differently between individuals with stroke and healthy-control individuals with the same levels of exercise. Individuals with stroke had worse physical activity levels than matched controls. Furthermore, different from individuals with stroke, in healthy-control individuals with different levels of exercise, the level of physical activity was similar.

Positive Effects of Probiotics on Motor Coordination and Brain during Moderate and High-Intensity Exercise in Adolescent Female Mice

Abstract Objectives This study aimed to investigate the effects of probiotics on inflammatory cytokines, neurotransmitters, and motor functions during different levels of exercise. Methods Female adolescent mice (n=140) were divided into two groups, of which one group was fed probiotics and the other group was not. For both groups, three levels of exercise were conducted: non-exercise, moderate-intensity exercise, and high-intensity exercise. Probiotics acquisition and aerobic treadmill exercise were the main variables during the growth period. We evaluated motor function with a rotarod test and analyzed cytokines and neurotransmitters in the cerebellum. Results In acceleration mode, the moderate and high-intensity exercise groups showed longer running times than the non-exercise groups (P&lt;0.001). Also, the probiotic-ingestion group had longer latency before falling than those who did not take probiotics in both the high-intensity and the non-exercise groups (P=0.002, P=0.002, respectively). In steady-state mode, the non-exercise group showed lower records compared with the moderate and high-intensity exercise groups (P=0.017, P=0.004, respectively). The inflammatory cytokine levels were high in the groups that performed moderate and high-intensity exercises, but the high levels were relieved in those taking probiotics. The GABA concentration was high for the exercise group and the probiotic-ingestion group. Conclusion Taken together, probiotics help improve motor skills during moderate and high-intensity exercise and help relieve inflammatory responses in the brain. Thus, we suggest that probiotics can be a useful supplement for brain and body development during exercise in adolescence.

Endurance exercise in seniors: Tonic, toxin or neither?

Cardiac adaptation to sustained exercise in the athletes is established. However, exercise-associated effect on the cardiac function of the elderly has to be elucidated. The aim of this study was to analyse left (LV) and right ventricular (RV) characteristics at different levels of chronic exercise in the senior heart. We studied 178 participants in the World Senior Games (mean age 68±8years, 86 were men; 48%). Three groups were defined based on the type and intensity of sports: low-, moderate- and high-intensity level. Exclusion criteria were coronary artery disease, atrial fibrillation, valvular heart disease or uncontrolled hypertension. LV and RV size and function were evaluated with an echocardiogram. LV trans-mitral inflow deceleration time decreased in parallel to the intensity of chronic exercise: 242±54ms in low-, 221±52ms in moderate- and 215±58ms in high-intensity level, p=.03. Left atrial volume index (LAVI) was larger in high-intensity group, p=.001. The LAVI remained significantly larger when adjusting for age, gender, heart rate, hypertension and diabetes (p=.002). LV and RV sizes were larger in the high-intensity group. LV ejection fraction and RV systolic function evaluated by tissue Doppler velocity, atrioventricular plane displacement and strain did not differ between groups. Left ventricular diastolic filling is not only preserved, but may also be enhanced in long-term, top-level senior athletes. Moreover, LV and RV systolic function remain unchanged at different levels of exercise. This supports the beneficial effects of endurance exercise participation in senior hearts.

Moderate levels of physical fitness maintain telomere length in non-senescent T CD8+ cells of aged men

OBJECTIVES:Immunosenescence is an age-associated change characterized by a decreased immune response. Although physical activity has been described as fundamental for maintaining the quality of life, few studies have evaluated the effects of different levels of exercise on telomere length in aged populations. The present study aimed to analyze the effects of different levels of physical activity, classified by the Maximal oxygen consumption (VO2 max) values, on the telomere length of memory Cluster of differentiation (CD) CD4+(CD45ROneg and CD45RO+), effector CD8+CD28neg, and CD8+CD28+ T cells in aged individuals.METHODS:Fifty-three healthy elderly men (aged 65-85 years) were included in this study. Their fitness level was classified according to the American College of Sports Medicine (ACSM) for VO2 max (mL/kg/min). Blood samples were obtained from all participants to analyze the percentage of CD3, CD4, CD8, CD28+, naïve, and subpopulations of memory T cells by using flow cytometry. Furthermore, using the Flow-FISH methodology, the CD4+CD45RO+, CD4+CD45ROneg, CD8+CD28+, and CD8+CD28negT cell telomere lengths were measured.RESULTS:There was a greater proportion of effector memory T CD4+ cells and longer telomeres in CD8+CD28+ T cells in the moderate physical fitness group than in the other groups. There was a higher proportion of terminally differentiated memory effector T cells in the low physical fitness group.CONCLUSION:A moderate physical activity may positively influence the telomere shortening of CD28+CD8+T cells. However, additional studies are necessary to evaluate the importance of this finding with regard to immune function responses in older men.

Moderate exercise improves function and increases adiponectin in the mdx mouse model of muscular dystrophy

The loss of dystrophin produces a mechanically fragile sarcolemma, causing muscle membrane disruption and muscle loss. The degree to which exercise alters muscular dystrophy has been evaluated in humans with Duchenne Muscular Dystrophy (DMD) and in mouse models including the mdx mouse but with inconsistent findings. We now examined two different levels of exercise, moderate and low intensity, in the mdx mouse model in the DBA2J background. mdx mice at 4–5 months of age were subjected to two different doses of exercise. We found a dose-dependent benefit for low and moderate exercise, defined as 4 m/min or 8 m/min, for 30 minutes three times a week. After six months, exercised mdx mice showed improved tetanic and specific force compared to the sedentary group. We also observed increased respiratory capacity manifesting as greater minute volume, as well as enhanced cardiac function mitigating the decline of fractional shortening that is normally seen. Exercised mdx mice also showed a dose-dependent increase in serum adiponectin with a concomitant reduced adipocyte cross sectional area. These findings identify moderate intensity exercise as a means to improve muscle performance in the mdx DBA2J mice and suggest serum adiponectin as a biomarker for beneficial exercise effect in DMD.

Effect of different levels of exercise on telomere length: A systematic review and meta-analysis

To investigate the effect of different levels of exercise on telomere length. CINAHL, SPORTDiscus (EBSCO), OVID (Medline) and EMBASE databases were searched for eligible studies. Methodological quality was evaluated using the Newcastle-Ottawa Scale, and heterogeneity among the studies was assessed using the I-squared test. When heterogeneity among studies was high (I2 > 50%), a random-effects model was used (Review Manager version 5, Cochrane Collaboration, Copenhagen, Denmark); otherwise, a fixed-effects model was used. Eleven eligible studies involving 19,292 participants were included in this meta-analysis. Longer telomere length was associated with physically active individuals, with a mean difference (MD) of 0.15 (95% confidence interval; 95% CI 0.05, 0.24); I2 = 99%. Longer telomere length was significantly associated with robust exercise (MD 0.08 (95% CI 0.04, 0.12)); I2 = 99%, as was moderate exercise (MD 0.07 (95% CI 0.03, 0.11)); I2 = 100%. Subgroup analysis revealed that longer telomere length was positively associated with exercise, regardless of sex, but was not statistically significant in elderly populations. Compared with inactive individuals, telomere lengths were longer in active subjects, regardless of the intensity of exercise.

Inspiratory muscle weakness contributes to exertional dyspnea in chronic thromboembolic pulmonary hypertension.

Determination of potentially-reversible factors contributing to exertional dyspnea remains an unmet clinical need in chronic thromboembolic pulmonary hypertension (CTEPH). Therefore, we aimed to evaluate the influence of inspiratory muscle weakness (IMW) on exercise capacity and dyspnea during effort in patients with CTEPH. We performed a prospective cross-sectional study that included thirty-nine consecutive patients with CTEPH (48 ± 15 yrs, 61% female) confirmed by right heart catheterization that underwent an incremental cardiopulmonary exercise test, 6-minute walk test and maximum inspiratory pressure (MIP) measurement. MIP < 70%pred was found in 46% of patients. On a multiple linear regression analysis, MIP was independently associated with 6MWD and . Patients with MIP < 70% presented greater than those with MIP ≥ 70%. Additionally, they also presented stronger sensations of dyspnea throughout exercise, even when adjusted for ventilation. At rest and at different levels of exercise, mean inspiratory flow (VT/TI) was significantly higher in patients with MIP < 70%. In conclusion, IMW is associated with a rapid increase of dyspnea, higher inspiratory load and poor exercise capacity in patients with CTEPH.

Exercise and Cancer Survivors: Lessons Learned from a Multi-Faceted Model for Exercise Prescription.

Cancer is the second leading cause of death, and the most common diagnosis among the general population is breast and colon cancer. Recently, an increasing number of new cases of invasive breast and colon cancer have been estimated, and more people die from these diseases. In addition to the genetic pattern, diet and lifestyle including smoking, alcohol consumption, and sedentary behaviour have also been identified as potential risks factors. Recent studies of cancer survivors have shown the beneficial effects of regular physical activity to reduce the prevalence of comorbidity, muscle atrophy, weight changes, reduced aerobic capacity, fatigue, depression, and reduced quality of life. Dedicated and individual programs are crucial for achieving the goals of improving quality of life and reducing comorbidities. A multidisciplinary approach is fundamental: lifestyle assessment, including estimating the level of physical activity, as well as nutritional habits, may be the first step. A periodic cardiovascular examination is crucial for detecting asymptomatic early myocardial failure. According to current ACSM guidelines, different levels of exercise (low-moderate 40% and moderate up to 60% of the maximal HR) may be prescribed, and patients enrolled may follow the exercise program if in the absence of contraindications. The current paper reports observations from our clinical practice and provides practical strategies that bridge contemporary, published guidelines into practice within a multi-disciplinary team working with cancer survivors in Italy.

A pilot randomized aerobic exercise trial in older HIV-infected men: Insights into strategies for successful aging with HIV.

BackgroundHIV-infected adults have increased risk for age-related diseases and low cardiorespiratory fitness that can be prevented and improved with exercise. Yet, exercise strategies have not been well studied in older adults with HIV and may require substantial adaptation to this special population.ObjectiveTo determine the safety and efficacy of aerobic exercise in older HIV-infected men in a randomized trial comparing different levels of exercise intensity.MethodsWe conducted a pilot exercise trial in 22 HIV-infected men ≥50 years of age receiving antiretroviral therapy who were randomized 1:1 to moderate-intensity aerobic exercise (Mod-AEX) or high-intensity aerobic exercise (High-AEX) that was performed three times weekly for 16 weeks in a supervised setting. Primary outcome was cardiorespiratory fitness (VO2peak) measured by treadmill testing. Secondary outcomes were exercise endurance, six-minute walk distance (6-MWD), body composition measured by Dual-energy X-ray absorptiometry (DXA), and fasting plasma levels of lipids and glucose.ResultsVO2peak increased in the High-AEX group (3.6 ±1.2 mL/kg/min, p = 0.02) but not in the Mod-AEX group (0.4 ±1.4 mL/kg/min, p = 0.7) with a significant between group difference (p<0.01). Exercise endurance increased in both the High-AEX group (27 ±11%, p = 0.02) and the Mod-AEX group (11 ±4%, p = 0.04). The 6-MWD increased in both the High-AEX (62 ±18m, p = 0.01) and the Mod-AEX group (54 ±14m, p = 0.01). Changes in VO2peak and 6-MWD were clinically relevant. There were no serious exercise-related adverse events. Dropouts were similar between group (27% overall) and were related to joint pain.ConclusionsThis pilot exercise trial demonstrates that moderate to high-intensity aerobic exercise in older HIV-infected men increases endurance and ambulatory function. However, increased cardiorespiratory fitness was observed only with high-intensity aerobic exercise despite substantial baseline impairment. Future research is needed to determine exercise strategies in older HIV-infected adults that address advanced aging and comorbidity yet are durable and feasible.

Extracorporeal Membrane Oxygenation for End-Stage Interstitial Lung Disease With Secondary Pulmonary Hypertension at Rest and Exercise: Insights From Simulation Modeling.

Interstitial lung disease (ILD) represents a collection of lung disorders with a lethal trajectory with few therapeutic options with the exception of lung transplantation. Various extracorporeal membrane oxygenation (ECMO) configurations have been used for bridge to transplant (BTT), yet no optimal configuration has been clearly demonstrated. Using a cardiopulmonary simulation, we assessed different ECMO configurations for patients with end-stage ILD to assess the physiologic deficits and help guide the development of new long-term pulmonary support devices. A cardiopulmonary ECMO simulation was created, and changes in hemodynamics and blood gases were compared for different inflow and outflow anatomic locations and for different sweep gas and blood pump flow rates. The system simulated the physiologic response of patients with severe ILD at rest and during exercise with central ECMO, peripheral ECMO, and with no ECMO. The output parameters were total cardiac output (CO), mixed venous oxygen (O2) saturation, arterial pH, and O2 delivery (DO2)/O2 utilization (VO2) at different levels of exercise. The model described the physiologic state of progressive ILD and showed the relative effects of using various ECMO configurations to support them. It elucidated the optimal device configurations and required physiologic pump performance and provided insight into the physiologic demands of exercise in ILD patients. The simulation program was able to model the pathophysiologic state of progressive ILD with PH and demonstrate how mechanical support devices can be implemented to improve cardiopulmonary function at rest and during exercise. The information generated from simulation can be used to optimize ECMO configuration selection for BTT patients and provide design guidance for new devices to better meet the physiologic demands of exercise associated with normal activities of daily living.

Swimming and diving energetics in dolphins: a stroke-by-stroke analysis for predicting the cost of flight responses in wild odontocetes

Exponential increases in hydrodynamic drag and physical exertion occur when swimmers move quickly through water, and underlie the preference for relatively slow routine speeds by marine mammals regardless of body size. Because of this and the need to balance limited oxygen stores when submerged, flight (escape) responses may be especially challenging for this group. To examine this, we used open-flow respirometry to measure the energetic cost of producing a swimming stroke during different levels of exercise in bottlenose dolphins (Tursiops truncatus). These data were then used to model the energetic cost of high-speed escape responses by other odontocetes ranging in mass from 42 to 2738 kg. The total cost per stroke during routine swimming by dolphins, 3.31±0.20 J kg-1stroke-1, was doubled during maximal aerobic performance. A comparative analysis of locomotor costs (LC; in Jkg-1stroke-1), representing the cost of moving the flukes, revealed that LC during routine swimming increased with body mass (M) for odontocetes according to LC=1.46±0.0005M; a separate relationship described LC during high-speed stroking. Using these relationships, we found that continuous stroking coupled with reduced glide time in response to oceanic noise resulted in a 30.5% increase in metabolic rate in the beaked whale, a deep-diving odontocete considered especially sensitive to disturbance. By integrating energetics with swimming behavior and dive characteristics, this study demonstrates the physiological consequences of oceanic noise on diving mammals, and provides a powerful tool for predicting the biological significance of escape responses by cetaceans facing anthropogenic disturbances.

تأثیر برنامج تدریبی بدنی مهاری على بعض المتغیرات الفسیولوجیة لطلاب جامعة طیبة دراسة تجریبیة. Comparative Study: The Effect of Physical and Skills Training Program on Some Physiological Variables on the University Undergraduate Student

تأثیر برنامج تدریبی بدنی مهاری على بعض المتغیرات الفسیولوجیة لطلاب جامعة طیبة دراسة تجریبیة. Comparative Study: The Effect of Physical and Skills Training Program on Some Physiological Variables on the University Undergraduate Student

Exergy model of the human heart

A precedent study about the effects of obesity on exergy behavior concluded that higher body fat per se does not lead to higher mortality among obese people; the focus must be turned to obesity-related diseases. Therefore, the next step towards the understanding of the effects of pathologies on the exergy behavior of human body is to analyze human heart. In the present work, an exergy model of human heart is developed. The heart is divided into two control volumes: the left heart, which pumps arterial blood from the lungs to the organs, and the right heart, which pumps venous blood from the organs to the lungs. Exergy of metabolism, exergy transfer associated to heat of metabolism, difference of exergy of blood flows and performed work are taken into account in the exergy balance for normotensive and hypertensive people under different levels of exercise. The left part of the heart is always responsible for more than 80% of the total exergy destruction. Moreover, a hypertensive heart destroys more exergy; this surplus value, when integrated along life cycle, represents 170 MJ/kg of destroyed exergy, which, according to the rate of living theory, would lead to a loss of 4.4 years in life expectancy.

Effects of exercise level on biomarkers in a rat knee model of osteoarthritis

The aim of this study was to elucidate whether the levels of serum biomarkers reflect the progression of osteoarthritis (OA) induced by different levels of exercise. Thirty-five Wistar rats subjected to anterior cruciate ligament transaction (ACLT) were divided into three groups: Control, moderate running, and intense running. Twelve rats (moderate running without ACLT) were allocated as a naive group. Running was performed on a motorized treadmill, at a speed of 18 m/min for 30 min/day (moderate and naive) or 60 min/day (intense) for 3 days per week. After 2 or 4 weeks, OA histopathology in the knees was evaluated using the Osteoarthritis Research Society International (OARSI) score, and the serum levels of cleaved collagen type II (C2C) and procollagen II C-propeptide (CPII) were analyzed. The OARSI score deteriorated in the intense running group after 2 weeks and the serum C2C/CPII ratio suggested the development of OA. At 4 weeks, the C2C/CPII ratio suggested there would be deterioration in the OARSI score but the score did not differ significantly between the moderate and intense running groups. C2C/CPII ratio had 13-25% correlation with the OARSI histological score. Thus, in rat experimental OA, the OARSI score could be partially predicted by the C2C/CPII ratio as a serum biomarker of OA.

The influence of internal and skin temperatures on active cutaneous vasodilation under different levels of exercise and ambient temperatures in humans

To clarify the influence of internal and skin temperature on the active cutaneous vasodilation during exercise, the body temperature thresholds for the onset of active vasodilation during light or moderate exercise under different ambient temperature conditions were compared. Seven male subjects performed 30 min of a cycling exercise at 20 % or 50 % of peak oxygen uptake in a room maintained at 20, 24, or 28 °C. Esophageal (Tes) and mean skin temperature (Tsk) as measured by a thermocouple, deep thigh temperature (Tdt) by the zero-heat-flow (ZHF) method, and forearm skin blood flow by laser-Doppler flowmetry (LDF) were monitored. The mean arterial pressure (MAP) was also monitored non-invasively, and the cutaneous vascular conductance (CVC) was calculated as the LDF/MAP. Throughout the experiment, the Tsk at ambient temperatures of 20, 24, and 28 °C were approximately 30, 32, and 34 °C, respectively, for both 20 % and 50 % exercise. During 50 % exercise, the Tes or Tdt thresholds for the onset of the increase in CVC were observed to be similar among the 20, 24, and 28 °C ambient conditions. During 20 % exercise, the increase in Tes and Tdt was significantly lower than those found at 50 %, and the onset of the increase in CVC was only observed at 28 °C. These results suggest that the onset of active vasodilation was affected more strongly by the internal or exercising tissue temperatures than by the skin temperatures during exercise performed at a moderate load in comparison to a light load under Tsk variations ranging from 30 °C to 34 °C. Therefore, the modification by skin temperature of the central control on cutaneous vasomotor tone during exercise may differ between different exercise loads.

Reverse Engineering of Oxygen Transport in the Lung: Adaptation to Changing Demands and Resources through Space-Filling Networks

The space-filling fractal network in the human lung creates a remarkable distribution system for gas exchange. Landmark studies have illuminated how the fractal network guarantees minimum energy dissipation, slows air down with minimum hardware, maximizes the gas- exchange surface area, and creates respiratory flexibility between rest and exercise. In this paper, we investigate how the fractal architecture affects oxygen transport and exchange under varying physiological conditions, with respect to performance metrics not previously studied.We present a renormalization treatment of the diffusion-reaction equation which describes how oxygen concentrations drop in the airways as oxygen crosses the alveolar membrane system. The treatment predicts oxygen currents across the lung at different levels of exercise which agree with measured values within a few percent. The results exhibit wide-ranging adaptation to changing process parameters, including maximum oxygen uptake rate at minimum alveolar membrane permeability, the ability to rapidly switch from a low oxygen uptake rate at rest to high rates at exercise, and the ability to maintain a constant oxygen uptake rate in the event of a change in permeability or surface area. We show that alternative, less than space-filling architectures perform sub-optimally and that optimal performance of the space-filling architecture results from a competition between underexploration and overexploration of the surface by oxygen molecules.