Wearable near-infrared spectroscopy: reliability and sensitivity among different endurance cycling exercise intensities

The present study investigated the reliability and sensitivity of a wearable near-infrared spectroscopy (wNIRS) device in moderate and heavy exercise intensity domains. On three separate days, eleven males performed an incremental test to exhaustion, and in the following visits, four submaximal constant-load bouts (i.e., test and retest) were performed in the moderate-intensity domain (100 and 130 W) and heavy-intensity domain (160 and 190 W). The local tissue oxygen saturation index (SmO2) and pulmonary oxygen uptake (V̇O2) were measured continuously. The absolute SmO2 and V̇O2 values and the change (Δ) from the 3rd to 6th min of exercise were calculated. There was good reliability for SmO2 measurements, as indicated by the high intraclass correlation coefficient analysis (ICC ≥0.84 for all) and low coefficient of variation between the two trials (CV ≤4.1% for all). Steady-state responses were observed for SmO2 and V̇O2 from the 3rd to the 6th min in the two moderate-intensity bouts (P>0.05), whereas SmO2 decreased and V̇O2 increased from the 3rd to the 6th min in the two heavy-intensity bouts (P<0.05). Together, these findings suggested that the SmO2 measured with a wNIRS device is reliable and sensitive to track local metabolic changes provoked by slight increments in exercise intensity.

Effect of smoking habit on cardiopulmonary function in patients with myocardial infarction -A study based on cardiopulmonary exercise testing- / 体力科学

The purpose of this study was to examine the relationship between smoking and cardiopulmonary function, and the effect of smoking habit on exercise tolerance after discharge from the hospital, focusing on CPX test data of patients hospitalized for acute myocardial infarction, and on CPX test data at 6 months after discharge. A total of 123 male patients hospitalized for acute myocardial infarction between April 2014 and December 2020 were included. Laboratory and CPX data were compared between smokers and non-smokers. CPX data of smokers, ex-smokers and non-smokers were also compared in 24 patients who underwent CPX examination 6 months after discharge. HDL-C was significantly decreased (p < 0.05) and τON was significantly prolonged (p < 0.05) during hospitalization in smokers. τON was significantly shorter only in ex-smokers (p < 0.05) 6 months after discharge compared to during hospitalization. These results suggest that τON, which reflects the oxygen uptake kinetics of peripheral tissues, is shortened by smoking cessation.

Respiratory gas kinetics in patients with congestive heart failure during recovery from peak exercise

Abstract Background Cardiopulmonary Exercise Testing (CPX) is essential for the assessment of exercise capacity for patients with Chronic Heart Failure (CHF). Respiratory gas and hemodynamic parameters such as Ventilatory Efficiency (VE/VCO2 slope), peak oxygen uptake (peak VO2), and heart rate recovery are established diagnostic and prognostic markers for clinical populations. Previous studies have suggested the clinical value of metrics related to respiratory gas collected during recovery from peak exercise, particularly recovery time to 50% (T1/2) of peak VO2. The current study explores these metrics in detail during recovery from peak exercise in CHF. Methods Patients with CHF who were referred for CPX and healthy individuals without formal diagnoses were assessed for inclusion. All subjects performed CPX on cycle ergometers to volitional exhaustion and were monitored for at least five minutes of recovery. CPX data were analyzed for overshoot of respiratory exchange ratio (RER=VCO2/VO2), ventilatory equivalent for oxygen (VE/VO2), end-tidal partial pressure of oxygen (PETO2), and T1/2 of peak VO2 and VCO2. Results Thirty-two patients with CHF and 30 controls were included. Peak VO2 differed significantly between patients and controls (13.5 ± 3.8 vs. 32.5 ± 9.8 mL/Kg*min−1, p < 0.001). Mean Left Ventricular Ejection Fraction (LVEF) was 35.9 ± 9.8% for patients with CHF compared to 61.1 ± 8.2% in the control group. The T1/2 of VO2, VCO2 and VE was significantly higher in patients (111.3 ± 51.0, 132.0 ± 38.8 and 155.6 ± 45.5s) than in controls (58.08 ± 13.2, 74.3 ± 21.1, 96.7 ± 36.8s; p < 0.001) while the overshoot of PETO2, VE/VO2 and RER was significantly lower in patients (7.2 ± 3.3, 41.9 ± 29.1 and 25.0 ± 13.6%) than in controls (10.1 ± 4.6, 62.1 ± 17.7 and 38.7 ± 15.1%; all p < 0.01). Most of the recovery metrics were significantly correlated with peak VO2 in CHF patients, but not with LVEF. Conclusions Patients with CHF have a significantly blunted recovery from peak exercise. This is reflected in delays of VO2, VCO2, VE, PETO2, RER and VE/VO2, reflecting a greater energy required to return to baseline. Abnormal respiratory gas kinetics in CHF was negatively correlated with peak VO2 but not baseline LVEF.

Time to achieve steady state for an accurate assessment of resting energy expenditure in adolescents with healthy weight and obesity: A cross-sectional study

ABSTRACT Objective: The present study investigated the time needed to achieve a steady state for an accurate assessment of resting energy expenditure (REE) in adolescents with healthy weight and obesity. Materials and methods: Thirty adolescents aged 12-17 years were assigned to a group with healthy weight (GHW; n = 12, body mass index [BMI] 22.5 ± 3.6 kg/m2) and another group with obesity (GO; n = 18, BMI 34.1 ± 5.2 kg/m2). Participants underwent test-retest reliability of REE assessment as follows: a) 24 h of abstention from physical exercise, soft drinks, or caffeine; b) fasting for ~12 h; c) acclimation period of 10 min; d) 30-min assessment in a supine position. Results and discussion: A significant change occurred during the 30 min in REE. Significant differences existed between consecutive means until the 20th and 25th min for the GHW and GO, respectively. Although significant differences between trials 1 and 2 were detected during the first 5-10 min of assessment, the REE for each 5-min time point exhibited high test-retest reliability across trials in both groups (intraclass correlation coefficients range 0.79-0.99). Conclusion: The following recommendations are provided to promote accurate assessment of REE among adolescents: a) initiate the REE assessment with 10 min of acclimation to decrease restlessness; b) determine REE for a minimum of 20 min if healthy weight and 25 min if obesity; c) determine REE for a further 5 min, with the average of this last 5 min of REE data being regarded as the REE.

Rational design of a 500 m3 fermenter for erythromycin production by Saccharopolyspora erythraea / 生物工程学报

Erythromycin is a macrolide antibiotic produced by Saccharopolyspora erythraea. Its yield is greatly affected by the fermentation conditions and the bioreactor configurations. In this study, a novel scale-up method for erythromycin fermentation was developed based on computational fluid dynamics (CFD) and time constant analysis. Firstly, the dissolved oxygen (DO) was determined as a key parameter according to the physiological properties of S. erythraea cultivated in a 50 L bioreactor. It was found that the time constant of oxygen supply (tmt) in a 500 m3 bioreactor should be less than 6.25 s in order to satisfy the organism's oxygen uptake rate (OUR). Subsequently, a 500 m3 bioreactor was designed using the time constant method combined with empirical correlations. The impeller combination with one BDT8 impeller at bottom and two MSX4 impellers at upper part was determined, and then validated by numerical simulation. The results indicated that the tmt of the bioreactor (< 6.25 s) and the fluid properties, including gas hold-up, shear stress and fluid vector, met the requirements of erythromycin fermentation. Finally, the industrial production of erythromycin in the 500 m3 showed the design method was applicable in large scale fermentation.

Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation

Abstract Objectives Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O2 pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE). Methods Thirty-one patients of both sexes, aged 45 to 75 years, with symptomatic (Canadian Cardiovascular Society class II to IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov: NCT03218891. Results The patients had low cardiorespiratory capacity (OUES of 1.74 ± 0.4 L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O2 pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R = 0.48; p = 0.019). Conclusion Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O2 pulse response during CEPT and contractile alterations detected by exercise stress echocardiography. Highlights OUES analysis is useful for assessing functional capacity in refractory angina. O2 pulse curve is correlated with contractile alterations in exercise echocardiogram. Cardiopulmonary exercise test is useful toll in patients with refractory angina.

Acute whole-body electromyostimulation associated with dynamic exercises did not alter cardiac autonomic modulation and oxygen uptake in obese and eutrophic men

Abstract Aim: To contrast the acute effects of whole-body electromyostimulation (WB-EMS) with sham associated with dynamic exercises on cardiovascular, ventilatory, metabolic, and autonomic responses in men with obesity and controls. Methods: A randomized cross-over and double-blind trial with nine eutrophic (23.6 years; 23 ± 1.4 kg/m2) and ten men with obesity (26 ± 4 years; 38 ± 7 kg/m2), who were randomized to receive WB-EMS-Sham or Sham-WB-EMS with 30 min of rest between protocols. WB-EMS protocol (Miha Bodytec®) was applied at the motor level, frequency = 85 Hz, pulse duration = 350 μs, cycle on = 6′; cycle off = 4′. Sham group performed the same exercises with the electric current turned off. Throughout both protocols, subjects executed two dynamic exercises of 5 minutes each (step-up and step down associated with shoulder flexion, and lunge exercise associated with elbow flexion) in the same order. R-R intervals and breath-by-breath respiratory gases analysis were collected during the protocols. Heart rate variability (HRV) indexes were obtained using linear and nonlinear analysis. The level of statistical significance was set at p < 0.05. Results: Regarding both exercises, participants with obesity presented reduced oxygen uptake, higher ventilation, respiratory rate, blood pressure, and Borg scores (p < 0.05) when contrasted with controls, as expected. However, no significant differences were found for HRV indexes between groups (p > 0.05). In addition, WB-EMS did not increase oxygen uptake or altered autonomic modulation when contrasted with sham in both groups (p < 0.05). Conclusion: Obesity has a negative impact on symptoms and functional capacity. However, WB-EMS did not acutely enhance oxygen uptake or HRV during exercise in a population with obesity.

Reference equations of oxygen uptake for the step test in the obese population

The aim of this study was to establish reference equations for the six-minute step test (6MST) based on demographic, anthropometric, body composition, and performance variables able to predict oxygen uptake (V̇O2) in obese individuals. Seventy-three obese adults (42±14 years old, body mass index >30 kg/m2) from both sexes were included. They underwent anamnesis, body composition evaluation, and the 6MST with expired gases registered simultaneously. Three equations were developed for the obese population (n=73; 59% female). The first equation was composed of the up-and-down step cycles (UDS), sex, and age as predictors; the second equation was composed of the UDS, age, and lean mass (LM). Both equations collectively explained 68.1% of the V̇O2 variance in the 6MST, while the third equation, composed of the UDS, age, and body mass, accounted for 67.7% of the V̇O2 variance. UDS, sex, age, LM, and body mass were important V̇O2 predictors of 6MST in these obese individuals. This study contributes to the dissemination of a simple, inexpensive, and fast evaluation method that can provide important indicators of cardiorespiratory fitness and guide strategies for rehabilitation.

Features of cardiopulmonary exercise test in patients with intermediate coronary stenosis / 中国康复理论与实践

ObjectiveTo review the clinical characteristics and capacity of cardiopulmonary exercise test in patients with intermediate coronary stenosis. MethodsFrom January, 2015 to January, 2020, the patients underwent coronary angiography and cardiopulmonary exercise test in Beijing Bo'ai Hospital were divided into intermediate coronary stenosis group (n = 184) and non-coronary heart disease group (n = 73). Symptoms, general information, laboratory and echocardiography information, results of cardiopulmonary exercise test were compared between two groups, and the main cardiovascular events during a year were observed. ResultsThe proportion of male (χ2 = 15.857, P < 0.001), smoking history (χ2 = 9.067, P = 0.003), hypertension history (χ2 = 15.087, P < 0.001) and hyperlipidemia history (χ2 = 13.507, P < 0.001) were more, and the level of hemoglobin A1c (Z = 2.431, P = 0.015) and high sensitivity C-reactive protein (Z = 2.108, P = 0.035) were higher in the intermediate coronary stenosis group, while less of them could reach anaerobic threshold (χ2 = 10.702, P = 0.001). The heard rate and respiratory exchange rate as anaerobic threshold decreased in the intermediate coronary stenosis group (Z > 2.156, P < 0.05). There was no significant difference in main cardiovascular events between the two groups within a year (P = 1.000). ConclusionCardiopulmonary capacity has been impaired in patients with intermediate coronary stenosis, who need to pay attention to the risk factors such as smoking, diabetes mellitus, hypertension and hyperlipidemia.

Parasympathetic modulation during sleep time is reduced after maximal exercise, correlated with aerobic fitness in young women / A modulação parassimpática durante o sono é reduzida após o exercício máximo e está correlacionada com a aptidão aeróbia em mulheres jovens

abstract It is known that cardiovascular risk is increased during exercise and recovery. Thus, it is necessary to assess all the risk associated with exercise to minimize the possibility of cardiovascular events. The aim of this study was to verify whether a maximal exercise alters ambulatory cardiac autonomic modulation in untrained women and whether aerobic fitness is correlated to cardiac autonomic modulation. Twelve women (25.35 ± 5.44 years) were outfitted with the Holter monitor on an experimental (after maximum exercise) and a control day to heart rate variability (HRV) evaluation. Maximal exercise increased 24 h heart rate (82 ± 14 vs 77 ± 11 bpm; p = 0.04) and during sleep time (72 ± 14 vs. 65 ± 9 bpm; p = 0.01), reduced parasympathetic modulation (HF - n.u. 49.96 ± 11.56 vs 42.10 ± 14.98; p = 0.04), and increased low-frequency/high-frequency ratio (2.88 ± 3.24 vs 1.31 ± 0.60; p = 0.03) during sleep time compared to the control day. Aerobic fitness was correlated positively with LF, HF, and HF (n.u.) indices (r = 0.61 to 0.73, p < 0.05) and correlated negatively with LF (n.u.) and LF/HF ratio (Rho = - 0.57 to - 0.69; p < 0.05). Maximal exercise alters parasympathetic modulation during sleep time in untrained women. Ambulatory cardiac autonomic modulation after exercise is related to aerobic fitness.

resumo Sabe-se que o risco cardiovascular aumenta durante o exercício e sua recuperação. Assim, é necessário avaliar todo o risco associado ao exercício para minimizar a chance de eventos cardiovasculares. Objetivou-se verificar se um exercício máximo altera a modulação autonômica cardíaca ambulatorial em mulheres não treinadas e se a aptidão aeróbia está correlacionada à modulação autonômica cardíaca. Doze mulheres (25,35 ± 5,44 anos) foram equipadas com monitor Holter em um dia experimental (após exercício máximo) e dia controle para avaliação da variabilidade da frequência cardíaca (VFC). O exercício máximo aumentou a frequência cardíaca de 24 h (82 ± 14 vs 77 ± 11 bpm; p = 0,04) e durante o sono (72 ± 14 vs 65 ± 9 bpm; p = 0,01), bem como reduziu a modulação parassimpática (HF - nu 49,96 ± 11,56 vs 42,10 ± 14,98; p = 0,04) e aumentou a razão de baixa frequência / alta frequência - LF/HF (2,88 ± 3,24 vs 1,31 ± 0,60; p = 0,03) durante o período do sono em comparação com o dia controle. A aptidão aeróbia foi correlacionada positivamente com os índices LF, HF e HF (nu) (r = 0,61 a 0,73, p <0,05) e negativamente correlacionada com LF (nu) e razão LF / HF (Rho = - 0,57 a - 0,69; p <0,05). O exercício máximo altera a modulação parassimpática durante o sono em mulheres não treinadas. A modulação autonômica cardíaca ambulatorial após o exercício foi correlacionada com a aptidão aeróbia.

Prevalence of Brazilian children and adolescents who met health criteria for aerobic fitness: systematic review update for Report Card Brazil Project / Prevalência de crianças e adolescentes brasileiros que atenderam aos critérios de saúde para aptidão aeróbia: atualização de revisão sistemática para o Projeto Report Card Brasil

abstract The aim of the study was to update Brazilian evidence on the prevalence of children and adolescents who met health criteria for aerobic fitness. This systematic review is part of the Report Card Brazil Project and the search was restricted to studies published during the period from January 2018 to December 2019 in nine electronic databases. Studies with different designs, which allowed extracting information about the prevalence of children and adolescents who met health criteria for aerobic fitness (age up to 19 years or average age up to 19 years) were included. Studies published from 2020 were not included due to the possible effect of the pandemic on this indicator and because there is no certainty as to when the pandemic will end. Of the 694 studies initially identified, 13 studies with information of 14,673 children and adolescents were included after reading titles, abstracts, full texts and references. The prevalence of children and adolescents who met health criteria for aerobic fitness was 26.9% (29.7% for girls; 44.6% for boys). In this search, eight different cutoff points were used to determine adequate aerobic fitness levels and five tests were used to determine aerobic fitness. Analyzing data from the present review with the previous systematic review of this project, one third of children and adolescents in Brazil meet health criteria for aerobic fitness.

resumo O objetivo do estudo foi realizar uma atualização das evidências brasileiras sobre a prevalência de crianças e adolescentes que atenderam aos critérios de saúde para aptidão aeróbia. Essa revisão sistemática integra o Projeto Report Card Brasil e a busca foi restrita aos estudos publicados durante o período de Janeiro de 2018 a Dezembro de 2019 em nove bases de dados eletrônicas. Estudos com diferentes delineamentos, os quais permitiram extrair informações acerca da prevalência de crianças e adolescentes que atenderam aos critérios de saúde para a aptidão aeróbia (idade até 19 anos ou com média de idade até 19 anos) foram incluídos. Estudos publicados a partir de 2020 não foram incluídos por conta do possível efeito da pandemia nesse indicador e por não haver uma certeza de quando finalizará a pandemia. Do total de 694 estudos inicialmente identificados, 13 estudos com informações de 14.673 crianças e adolescentes foram incluídos após a leitura de títulos, resumo, textos completos e referências. A prevalência de crianças e adolescentes que atenderam aos critérios de saúde para aptidão aeróbia foi de 26.9% (29,7% para as meninas; 44,6% para os meninos). Nessa busca, oito pontos de corte distintos para determinar níveis adequados de aptidão aeróbia foram utilizados, bem como cinco testes foram empregados para se determinar a aptidão aeróbia. Analisando-se os dados da presente revisão com a revisão sistemática anterior desse projeto, um terço das crianças e adolescentes do Brasil atendem aos critérios de saúde para aptidão aeróbia.

Footwear designed to enhance energy return improves running economy compared to a minimalist footwear: does it matter for running performance?

The present study compared the effects of a footwear designed to enhance energy return (thermoplastic polyurethane, TPU) vs minimalist shoes on running economy (RE) and endurance performance. In this counterbalanced and crossover design study, 11 recreational male runners performed two submaximal constant-speed running tests and two 3-km time-trials with the two shoe models. Oxygen uptake was measured during submaximal constant-speed running tests in order to determine the RE at 12 km/h and oxygen cost of running (CTO2) at individual average speed sustained during the 3-km running time-trials wearing either of the two shoes. Our results revealed that RE was improved (2.4%) with TPU shoes compared with minimalist shoes (P=0.01). However, there was no significant difference for CTO2 (P=0.61) and running performance (P=0.52) comparing the TPU (710±60 s) and the minimalist (718±63 s) shoe models. These novel findings demonstrate that shoes with enhanced mechanical energy return (i.e. TPU) produced a lower energy cost of running at low (i.e., 12 km/h) but not at high speeds (i.e., average speed sustained during the 3-km running time-trial, ∼15 km/h), ultimately resulting in similar running performance compared to the minimalist shoe.

Interval training during concurrent training optimizes cardiorespiratory adaptations in women / Exercício intervalado durante o treinamento concorrente otimiza as adaptações cardiorrespiratórias em mulheres

Abstract This study compared the effects of using continuous and interval aerobic exercise during concurrent training on cardiorespiratory adaptations in women. Thirty-two participants were randomly assigned into one of the following groups: continuous running and resistance training (C-RUN, n = 10), interval running and resistance training (I-RUN, n = 11), or control group that performed resistance training only (RT, n = 11). Each group trained twice a week during 11 weeks. Oxygen uptake corresponding to the first ventilatory threshold (VO2VT1), second ventilatory threshold (VO2VT2) and maximal effort (VO2max) was measured in a maximal incremental test performed before and after training. Significant increases in VO2VT1, VO2VT2 and VO2max were observed in all training groups. VO2VT2 and VO2max presented time-group interactions, indicating that the magnitude of the increase in these variables was dependent on the training group (VO2VT2: C-Run = 6.6%, I-Run = 15.7%, RT = 1.7%; VO2max: C-Run = 7.2%, I-Run = 14.3%, RT = 2.7%). The effect size observed for post-training values comparing C-RUN and RT groups was d = 0.566 for VO2VT2 and d = 0.442 for VO2max. On the other hand, values of d = 0.949 for VO2VT2 and d = 1.189 for VO2max were verified between I-RUN and RT groups. In conclusion, the use of continuous and interval aerobic exercise during concurrent training improved different cardiorespiratory parameters in women, but in a greater magnitude when interval aerobic exercise was performed simultaneously to resistance training.

Resumo O presente estudo comparou os efeitos do uso de exercício aeróbio contínuo e intervalado durante o treinamento concorrente nas adaptações cardiorrespiratórias de mulheres. Trinta e duas participantes foram randomizadas em três grupos de treinamento: corrida contínua + treinamento resistido (C-RUN, n = 10), corrida intervalada + treinamento resistido (I-RUN, n = 11), e apenas treinamento resistido (RT, n = 11). Cada grupo treinou 2 vezes por semana ao longo de 11 semanas. Foi avaliado o consumo de oxigênio correspondente ao primeiro (VO2VT1) e segundo (VO2VT2) limiar ventilatório, bem como o consumo máximo de oxigênio (VO2max) antes e depois dos treinamentos. Foram encontrados aumentos significativos no VO2VT1, VO2VT2 e VO2max ao final do período de treinamento nos três grupos. Ainda, foi encontrada interação tempo*grupo nas variáveis VO2VT2 e VO2max , sugerindo que a magnitude de alteração foi dependente do tipo de treinamento realizado (VO2VT2: C-Run = 6,6%, I-Run = 15,7%, RT = 1,7%; VO2max: C-Run = 7,2%, I-Run = 14,3%, RT = 2,7%). Da mesma forma, diferentes tamanhos de efeito foram observados ao final do treinamento, de acordo com a intervenção realizada (C-RUN versus RT d = 0,566 para o VO2VT2 e d = 0,442 para o VO2max; I-RUN versus RT d = 0,949 para o VO2VT2 e d = 1,189 para o VO2max). Embora o uso de exercício aeróbio contínuo e intervalado durante o treinamento concorrente tenha sido efetivo em promover adaptações cardiorrespiratórias em mulheres, os ganhos obtidos foram maiores quando o exercício intervalado foi associado ao exercício resistido.

Factors influencing exercise tolerance after stroke / 中华物理医学与康复杂志

Objective:To observe the recovery of exercise tolerance among stroke survivors using the cardiopulmonary exercise test (CPET) and analyze the factors influencing it.Methods:A total of 81 stroke survivors hospitalized in the Department of Rehabilitation Medicine of our hospital in year 2018 and 2019 were selected. The general clinical data of all patients were collected retrospectively and combined with the data from CPET to establish a data set. Version 25.0 of the SPSS software was used for multiple linear regressions analysis, with the peak oxygen uptake as the dependent variable, and the age, Brunnstrom stage, peak power, peak heart rate, peak respiratory exchange ratio, peak breathing reserve, peak ventilation per minute, the slope of the VE-VCO 2 curve (ΔVE/ΔVCO 2) and peak end tidal partial pressure of carbon dioxide as independent variables. Results:Stroke survivors at Brunnstrom stage III Ⅲ, Ⅳ and Ⅴ or higher decreased sequentially with their age, but their peak oxygen uptake increased gradually. The multiple linear regression model constructed by " stepwise method" showed that the fitted multiple linear regression equation was statistically significant ( F=100.228, P<0.001). Moreover, the average peak power, peak heart rate, peak ventilation per minute and the slope of the VE-VCO 2 curve were all found to be significant independent predictors of peak oxygen uptake in these stroke survivors. Conclusions:Skeletal muscle power, cardiac function, pulmonary ventilation and ventilation efficiency are useful independent predictors of the exercise tolerance of stroke survivors.

Use of sports tourism to motivate older adults to maintain increased aerobic exercise capacity and reduced arterial stiffness after supervised training: a non-randomized controlled trial / 体力科学

Habitual aerobic exercise decreases arterial stiffness, a risk factor for cardiovascular disease, and increases aerobic exercise capacity. Exercise habits can be difficult to maintain over time. We sought to determine if the prospect of participating in a sports tourism event (mountain climbing) helped older adults maintain increased aerobic exercise capacity and decreased arterial stiffness after a supervised training program. Forty community-dwelling middle-aged and older individuals were divided into training (n=20) and control (n=20) groups. The training group participated in six weeks of face-to-face exercise intervention (walking, 60%–75% of age-predicted maximal heart rate, 35–50 min/day, 1 day/week) and was additionally offered home-based walking (45 min/day, 2–4 days/week). During the same period, the control group was asked not to change their lifestyle. In the last session of the exercise program, we announced a mountain climbing event planned for six months in the future. The participants were encouraged to maintain their exercise habits leading up to the event. Arterial stiffness (brachial-ankle pulse wave velocity) and maximal oxygen uptake were measured before and after the six-week intervention and two weeks before the mountain climbing event. In the training group, arterial stiffness decreased, and maximal oxygen uptake increased after the intervention; these improvements were successfully maintained until the mountain climbing event. These parameters did not change significantly in the control group. Sports tourism may motivate older adults to maintain their exercise habits after a supervised training program.

Effects of pre-exercise ingestion of different amounts of carbohydrate at three hours after feeding breakfast on exercise-induced hypoglycemia / 体力科学

The purpose of this study was to compare effects of different amounts of carbohydrate (CHO) in beverage on plasma glucose (GLU) concentration during exercise after feeding breakfast. Seven healthy Japanese male subjects performed 30-min cycling at an intensity on the 75% of maximal load at 3-h after feeding breakfast under 3 types of CHO (0 g, 30 g and 150 g) beverage conditions. The subjects ingested 500 mL of beverage dissolved each amount of glucose at 30-min before the exercise. The GLU concentrations were measured at 35- and 10-min before the exercise and every 5-min during the exercise. The minimum GLU concentrations under the 30 g condition for all subjects were lower than a criterion for hypoglycemic (72 mg / dL). The mean value also fell below the criterion at from 10- to 20-min during exercise. The minimum GLU concentration under the 150 g condition of only one subject was lower than the criterion, but the mean value did not fall below the criterion. Significant negative correlations were found between the subjects’ maximum oxygen uptake (VO2max) and the decreases in GLU concentration from maximum to minimum under both the 30 g (r = -0.947, p < 0.01) and 150 g conditions (r = -0.884, p < 0.01). This study clarified that feeding breakfast at 3-h before the exercise followed by the 30 g CHO beverage ingestion at 30 min before the exercise induced exercise-induced hypoglycemia, and that the subjects with higher VO2max had the greater decreases in GLU concentration.

Comparação das respostas fisiológicas do incremental shuttle walk test e do Glittre-ADL test: instrumentos complementares para avaliação da capacidade funcional / Comparación de las respuestas fisiológicas de incremental shuttle walk test y de Glittre-ADL test: instrumentos complementarios para evaluar la capacidad funcional / Comparison of the physiological responses of the Incremental Shuttle Walk test and Glittre-ADL test: complementary instruments for the evaluation of functional capacity

RESUMO O objetivo deste estudo foi avaliar e comparar respostas metabólicas, cardiovasculares e ventilatórias do incremental shuttle walk test (ISWT) e do Glittre activities of daily living test (Glittre-ADL test). Trata-se de um estudo transversal, realizado com indivíduos saudáveis. A capacidade funcional (CF) foi avaliada pela distância percorrida e consumo de oxigênio pico (VO2pico) no ISWT e pelo tempo gasto e VO2 no Glittre-ADL test. Trinta indivíduos percorreram 656,67 (IC95%:608,8-704,5) metros no ISWT e executaram o Glittre-ADL test em 2,4 (IC95%:2,2-2,6) minutos. O VO2 pico do ISWT foi 27,8 (IC95%25,6-29,9) versus 22,2 (IC95%20,5-24,1)mL×kg−1×min−1 (p<0,001) no estado estável (EE) do Glittre-ADL test. As correlações entre distância percorrida no ISWT e o tempo gasto no Glittre-ADL test, o VO2pico do ISWT e o VO2 no EE do Glittre-ADL test e a FC no pico do ISWT e no EE do Glittre-ADL test foram de moderada a alta magnitude. O Glittre-ADL test apresenta menores respostas metabólicas, cardiovasculares e ventilatórias se comparado ao ISWT.

RESUMEN El presente estudio tuvo el objetivo de evaluar y comparar las respuestas metabólicas, cardiovasculares y ventilatorias de incremental shuttle walk test (ISWT) y de Glittre activities of daily living test (Glittre-ADL test). Es un estudio transversal realizado con individuos sanos. La capacidad funcional (CF) se evaluó utilizando la distancia recorrida y consumo máximo de oxígeno (VO2máx) en el ISWT y el tiempo empleado y VO2 en el Glittre-ADL test. Treinta individuos caminaron 656,67 (IC95%:608,8-704,5) metros en el ISWT y realizaron el Glittre-ADL test en 2,4 (IC95%:2,2-2,6) minutos. El VO2 máx del ISWT fue de 27,8 (IC95%25,6-29,9) versus 22,2 (IC95%20,5-24,1)mL×kg−1×min−1 (p<0,001) en el estado estable (EE) del Glittre-ADL test. Las correlaciones entre la distancia recorrida en el ISWT y el tiempo empleado en el Glittre-ADL test, el VO2máx del ISWT y el VO2 en el EE de Glittre-ADL test y la FC en el máximo del ISWT y en el EE de Glittre-ADL test fueron de moderada a alta magnitud. El Glittre-ADL test presenta respuestas metabólicas, cardiovasculares y ventilatorias más bajas en comparación con el ISWT.

ABSTRACT The aim of the study was to assess and compare the cardiovascular, ventilatory and metabolic responses of the Incremental Shuttle Walk test (ISWT) and Glittre Activities of Daily Living test (Glittre-ADL test). This is a cross-sectional study with individuals. The functional capacity (FC) was evaluated by distance and peak oxygen consumption (VO2peak) in the ISWT and time spent and VO2 in Glittre-ADL test. Thirty individuals went through 656.67 (CI95%:608.8-704.5) meters at the ISWT and performed the Glittre-ADL test in 2.4 (CI95%:2.2-2.6) minutes. The peak VO2 of the ISWT was 27.8 (CI95%25.6-29.9) vs. 22.2 (CI95%20.5-24.1) mL×kg−1×min−1 (p<0.001) in the steady state (SS) of the Glittre-ADL test. Correlations between distance traveled in the ISWT and the time spent in Glittre-ADL test, VO2 peak of ISWT and VO2 in SS of Glittre-ADL test and HR at the ISWT peak and at the Glittre-ADL test SS were moderate to high magnitude. The Glittre-ADL test has lower metabolic, cardiovascular and ventilatory responses compared to ISWT, despite correlations between variables.

Graded and ramp protocols present similar results in apparently healthy subjects / Protocolo escalonado e de rampa apresentam resultados similares em indivíduos aparentemente saudáveis

Abstract The aim of the study was to compare maximum oxygen uptake, maximum heart rate, speed corresponding to VO2max, time to exhaustion, and ventilatory thresholds between two maximal test protocols (scaled vs ramp) with equalized metabolic demand in apparently healthy young adults. Twenty-seven subjects of both sexes were analyzed and submitted to two maximum tests: 1) scaled test with 1.2 km∙h-1 every 2 min; 2) ramp test with 0.1 km∙h-1 every 0.18 min; both with 1% slope and maximum total duration of twenty minutes. Respiratory gas exchanges were directly analyzed, and ventilatory thresholds determined through visual inspection. Central tendency and dispersion measures were adopted, as well as paired t-test and effect size. Bland-Altman analysis verified the agreement among variables. Maximum speed showed significance difference (p < 0.01) for the scaled test (14.0 ± 1.9 km∙h-1) and ramp test (14.6 ± 2.3 km∙h-1). Even with small BIAS values, negative trend and high limits of agreement could be observed. Despite the non-difference presented for variables, except for maximum speed, it could be concluded that the scaled test is able to determine the analyzed variables similar to the ramp test, considering the same conditions of the present study.

Resumo O objetivo do estudo foi comparar o consumo máximo de oxigênio (VO2máx), frequência cardíaca (FC) máxima velocidade associada ao VO2máx, tempo até a exaustão e limiares ventilatórios entre dois protocolos de teste máximo (escalonado vs. rampa) com demanda metabólica equalizada em jovens adultos aparentemente saudáveis. Vinte e sete sujeitos de ambos os sexos foram analisados e submetidos à dois testes máximos: 1) escalonado com 1,2 km•h-1 a cada 2 min; 2) rampa com 0,1 km•h-1 a cada 0,18 min; ambos com 1% de inclinação e duração total máxima prevista de vinte minutos. As trocas respiratórias foram analisadas diretamente, e os limiares ventilatórios determinados por inspeção visual. Medidas de tendência central e dispersão foram adotadas, assim como um teste t pareado e tamanho do efeito. A análise de Bland-Altman verificou a concordância entre as variáveis. A única variável a apresentar diferença estatística (p < 0,01) foi a velocidade máxima (escalonado = 14,0 ± 1,9 km•h-1) e (rampa = 14,6 ± 2,3 km∙h-1). Mesmo com baixos valores de BIAS, é possível verificar uma tendência negativa assim como altos limites de concordância. Apesar da não diferença apresentada para as variáveis, exceto para a velocidade máxima, é possível afirmar que o teste escalonado é capaz de determinar as variáveis analisadas de modo semelhante ao teste rampa considerando as mesmas condições do presente estudo.

The validity of Keiser-M3 stationary bicycle with standard ergometer for physiological measurements associated with maximum effort

Abstract Aim: This study aims to investigate the concordance between two cycle ergometers for variables measured in the test of maximum incremental effort. Methods: This correlation study enrolled 15 inactive women (19,2 ± 4,0 years old). At random, the participants performed two maximal effort incremental tests (MEIT), using cycle ergometers (Keiser-M3 and Ergo-167) on different days with a minimum interval of 72 hours. The test had stages of two minutes, and two-step increments were carried out at the end of each stage. Lactate concentration ([LAC]), and rated perceived exertion (RPE) were collected, in addition to monitoring oxygen uptake (VO2) and heart rate (HR). The Paired t-test was carried out to compare physiologic variables, Lin's test was used for correlation, and Bland Altman was used to measuring concordances among variables. Results: The correlations between physiologic parameters were considered strong for HR on the anaerobic threshold (Keiser M3 = 146 ± 14 bpm; Ergo-167 = 149 ± 9 bpm; r = 0.762), greater blood lactate value (Keiser M3 = 9,97 ± 2,51 mmol/L; Ergo-167 = 9.71 ± 2.56 mmol/L; r = 0.820), VO2max (Keiser M3 = 38,37 ± 6,97 mL/kg/min; Ergo-167 = 36.06 ± 8.4 mL/kg/min; r = 0,806) and HRmax (Keiser M3 = 186 ± 53 bpm; Ergo-167 = 188 ± 11 bpm; r = 0.716). Conclusion: The results show the feasibility of using the cycle ergometer Keiser, model M3, to perform the maximal effort incremental test, whereas there was high concordance in the physiologic responses in both ergometers for inactive women.

Effects of high- and moderate-intensity exercise on central hemodynamic and oxygen uptake recovery kinetics in CHF-COPD overlap

The oxygen uptake (V˙O2) kinetics during onset of and recovery from exercise have been shown to provide valuable parameters regarding functional capacity of both chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) patients. To investigate the influence of comorbidity of COPD in patients with CHF with reduced ejection fraction on recovery from submaximal exercise, 9 CHF-COPD male patients and 10 age-, gender-, and left ventricle ejection fraction (LVEF)-matched CHF patients underwent constant-load exercise tests (CLET) at moderate and high loads. The V˙O2, heart rate (HR), and cardiac output (CO) recovery kinetics were determined for the monoexponential relationship between these variables and time. Within-group analysis showed that the recovery time constant of HR (P<0.05, d=1.19 for CHF and 0.85 for CHF-COPD) and CO (P<0.05, d=1.68 for CHF and 0.69 for CHF-COPD) and the mean response time (MRT) of CO (P<0.05, d=1.84 for CHF and 0.73 for CHF-COPD) were slower when moderate and high loads were compared. CHF-COPD patients showed smaller amplitude of CO recovery kinetics (P<0.05) for both moderate (d=2.15) and high (d=1.07) CLET. Although the recovery time constant and MRT means were greater in CHF-COPD, CHF and CHF-COPD groups were not differently affected by load (P>0.05 in group vs load analysis). The ventilatory efficiency was related to MRT of V˙O2 during high CLET (r=0.71). Our results suggested that the combination of CHF and COPD may further impair the recovery kinetics compared to CHF alone.