Incremental Exercise Protocol Research Articles

Jacketed telemetry in rats: a novel non-invasive method for cardiorespiratory phenotyping during treadmill exercise.

The development of alternative methods for monitoring cardiorespiratory function without restraint or surgical implantation is attracting growing interest for both ethical and scientific reasons. For this purpose, a new non-invasive jacketed telemetry tool consisting in a radio device maintained in a jacket worn by the animal was previously developed to improve cardiorespiratory monitoring. It allows simultaneous monitoring of cardiac activity by surface electrocardiagram, respiratory function by respiratory inductive plethysmography, and locomotor activity by accelerometry. However, this tool has only been validated under conditions of low/intermediate activity levels or in anesthetized animals. This study aimed to evaluate the feasibility of using this system in the challenging conditions of an exertion protocol. Male Wistar rats (n = 10, 8-9 weeks old) were subjected to an incremental treadmill exercise protocol including speed levels from 5 to 40 cm s-1 separated by 30-s breaks. Heart rate (HR) and minute ventilation (assessed by minute volume; MV) were continuously monitored. At the end of each running level and during the 30-s breaks, HR and MV showed a significant increase compared to resting values. They returned to the baseline within 60 min of post-exercise recovery. Overall, our results demonstrated (i) the ability of the animal to run while wearing the device and (ii) the ability of the device to reliably monitor cardiorespiratory adaptation to treadmill exercise despite significant mechanical disturbances. In conclusion, this study highlights the possibility of non-invasively monitoring cardiorespiratory functional variables that were previously unattainable under conditions of high activity in freely moving animals.

The Respiratory Compensation Point: Mechanisms and Relation to the Maximal Metabolic Steady State.

At a point during the latter third of an incremental exercise protocol, ventilation begins to exceed the rate of clearance of carbon dioxide (CO2) at the lungs ( CO2). The onset of this hyperventilation, which is confirmed by a fall from a period of stability in end-tidal and arterial CO2 tensions (PCO2), is referred to as the respiratory compensation point (RCP). The mechanisms that contribute to the RCP remain debated as does its surrogacy for the maximal metabolic steady state of constant-power exercise (i.e., the highest work rate associated with maintenance of physiological steady state). The objective of this current opinion is to summarize the original research contributions that support and refute the hypotheses that: (i) the RCP represents a rapid, peripheral chemoreceptor-mediated reflex response engaged when the metabolic rate at which the buffering systems can no longer constrain the rise in hydrogen ions ([H+]) associated with rising lactate concentration and metabolic CO2 production is surpassed; and (ii) the metabolic rate at which this occurs is equivalent to the maximal metabolic steady state of constant power exercise. In doing so, we will shed light on potential mechanisms contributing to the RCP, attempt to reconcile disparate findings, make a case for its adoption for exercise intensity stratification and propose strategies for the use of RCP in aerobic exercise prescription.

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.

Metabolic dysfunction in the myocardium three months after exertional heat stroke in mice

In humans, exposure to heat stroke has proven to be a risk factor for development of cardiovascular disease later in life. We hypothesized that exposure to exertional heat stroke (EHS) would result in the development of similar long-term cardiac disease in mice. In this study we followed mice for three months after EHS, using ultrasound imaging of the heart, metabolomics and histological analysis of ventricular tissue and biomarker analysis after 4 weeks of recovery. Methods: Mice were instrumented with temperature telemetry devices and were trained to run on forced running wheels using an incremental exercise protocol. EHS mice ran in an temperature elevated environmental chamber; females 37.5°C; males 34°C; whereas, matched exercise control mice (EXC) ran in 22-23°C. Running stopped when EHS mice reached symptom limitation (unconsciousness). The mice were followed for 12 wks post EHS, with two ultrasound measures at 2 and 10 wks of recovery. At the end of the study, mice were anesthetized, a blood sample drawn, and ventricular tissue collected for metabolomics. RESULTS: Male but not female EHS mice gained ~10% greater body mass compared to EXC over the course of recovery ( P<0.01). Hearts from male but not female EHS mice exhibited elevations in heart mass per tibia length ( P<0.01). At three months, metabolomics in male EHS hearts revealed significant elevations in glucose and glucose metabolites and significant decreases in acylcarnitines consistent with a metabolic shift toward glucose and away from lipid metabolism. In contrast, female hearts exhibited fewer abnormalities but with significant elevations in lipid and arachidonate metabolites. At two weeks post, there were no differences in male ultrasound measures between EHS and EXC mice but in females there was a reduced posterior wall velocity ( P=0.012) and a trend towards narrower posterior wall thickness ( P= 0.06) . Between 2 and 12 wks post EHS, there were significant elevations in fractional shortening in males ( P<0.05) and elevations in posterior wall velocity ( P<0.01). In contrast, females exhibited significant reductions posterior wall velocity. From blood samples, male EHS mice had increased HDL and females exhibited decreased HDL (p<0.01 in both). LDL increased only in males P<0.05. Vascular adhesion molecules sICAM ( P<0.01) and Pecam1 ( P<0.01) were significantly decreased in EHS males and females and e-Selectin was decreased in EHS males only ( P<0.001). Total serum protein was significantly reduced in both male and females ( P<0.01). Male EHS mice also exhibited significant elevations in white blood cell count and total lymphocytes ( P=0.01) suggesting ongoing activation of the immune system . CONCLUSIONS: In this controlled preclinical model of EHS, both male and female mice exhibited long-lasting cardiovascular and systemic disorders that could account for the lingering incidence of cardiovascular disease and poor overall health in heat stroke victims. Supported by US Army Med. Research and Devel. Command BA180078 and the BK and Betty Stevens Endowment. 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.

Submaximal, Low-Dose Eccentric vs Traditional Cycling Exercise: Reduced Oxygen Uptake and Pulmonary Artery Pressure Assessed by Echocardiography in Healthy Middle-aged Adults. A Randomized Controlled, Crossover Trial

ObjectiveTo investigate the ventilatory and circulatory differences between eccentric (ECC) and concentric (CON) cycling exercise at submaximal, low-dose intensity from onset to end-exercise in healthy middle-aged participants. DesignRandomized controlled crossover trial. SettingThe participants underwent 1 ECC and 1 CON test according to stepwise incremental exercise protocols at identical, submaximal intensities. Breath-by-breath analyses of ventilatory gas exchange and echocardiography were used to assess cardiopulmonary function during exercise. Participants24 healthy middle-aged, untrained participants (14 women, 10 men, 50±14 years) were included. Interventions1 ECC and 1 CON test at submaximal intensities. Main Outcome MeasureThe main outcome was oxygen uptake (V'O2). ResultsThe V'O2 increase was reduced by -422 mL/min (-52%, 95% confidence interval: -513 to -292, P<.001) during ECC, as well as the ventilatory drive. Echocardiographic parameters, heart rate (-14%), cardiac output (-21%), stroke volume (-15%), and pulmonary artery pressure by tricuspid regurgitation pressure gradient (TRPG) (-26%) were also significantly reduced during ECC compared with CON at identical intensities. Participants reported significantly less dyspnea and unchanged perceived leg fatigue in ECC. ConclusionECC was well tolerated, and significant reductions were observed in V'O2, ventilation, and right ventricular load compared with CON, even at low intensity levels. This study, conducted on healthy middle-aged participants, did not raise concerns that would hinder further investigation of the effects of ECC in patients with severely limited cardiopulmonary disease, and it calls for further research on this topic.

Heat production during exercise in pregnancy: discerning the contribution of total body weight.

Studies have reported enhanced thermoregulatory function as pregnancy progresses; however, it is unclear if differences in thermoregulation are attributed to weight gain or other physiological changes. This study aimed to determine if total body weight will influence thermoregulation (heat production (Hprod)), heart rate, and perceptual measurements in response to weight-bearing exercise during early to late pregnancy. A cross-sectional design of healthy pregnant women at different pregnancy time points (early, T1; middle, T2; late, T3) performed a 7-stage weight-bearing incremental exercise protocol. Measurements of Hprod, HR, and RPE were examined. Two experimental groups were studied: (1) weight matched and (2) non-weight matched, in T1, T2, and T3. During exercise, equivalent Hprod at T1 (326 ± 88kJ), T2 (330 ± 43kJ), and T3 (352 ± 52kJ) (p = 0.504); HR (p = 0.830); and RPE (p = 0.195) were observed in the WM group at each time point. In the NWM group, Hprod (from stages 1-6 of the exercise) increased across pregnancy time points, T1 (291 ± 76kJ) to T2 (347 ± 41kJ) and T3 (385 ± 47kJ) (p < 0.001). HR increased from T1 to T3 in the warm-up to stage 6 (p = 0.009). RPE did not change as pregnancy time point progressed (p = 0.309). Total body weight, irrespective of pregnancy time point, modulates Hprod and HR during exercise. Therefore, accounting for total body weight is crucial when comparing thermoregulatory function during exercise across pregnancy.

TAPSE/sPAP at peak exercise as a surrogate of RV-PA uncoupling can predict exercise-induced pulmonary hypertension in symptomatic patients with chronic thromboembolic pulmonary disease

Abstract Background and aim Chronic thromboembolic disease (CTED) refers to the presence of chronic thrombotic pulmonary vascular occlusion in the absence of pulmonary hypertension (PH) at rest but with exercise limitation caused by established vasculopathy. Symptoms after an acute pulmonary embolism (PE) with persistent lung perfusion defects need a complete diagnostic approach. Exercise echocardiography (ex-echo), with surrogate parameters of ventricular-arterial (VA) coupling could be of interest to non-invasively assess a pathological hemodynamic response. The aim of this study is to analyze the role of ex-echo and non-invasive assessment of VA coupling by echocardiography in predicting an abnormal hemodynamic response in symptomatic patients with chronic thrombotic pulmonary vascular occlusion. Methods Symptomatic patients with confirmed perfusion defects in lung V/Q scintigraphy despite optimal anticoagulant therapy for at least 3 months after an acute PE were selected. Relevant PH at rest was ruled-out (mPAP &amp;lt;25 mmHg, PVR &amp;lt;3 Wu, PAWP &amp;lt;15 mmHg, according to available definition at the time). Right heart catheterization with incremental exercise protocol (adapted cycle ergometer), with simultaneous transthoracic echo were performed. Parameters were collected at each exercise level. A mPAP/CO slope &amp;gt;3 mmHg·L−1·min−1 measured invasively was considered an abnormal hemodynamic response to exercise. Right VA coupling was estimated as TAPSE/sPAP ratio. A non invasive echo mPAP/CO slope was obtained from Doppler measurements. Results 31 patients (32% women, mean age 51.8 ± 14.7 y.) were included. Fourteen patients (45%) developed ex-PH. Baseline and peak exercise characteristics and parameters according to hemodynamic response are shown in Table 1. Moderate significative correlations between invasive hemodynamics and echo derived parameters at peak exercise were observed: sPAP: r=0.793 (p &amp;lt;0.001), CO r=0.532 (p 0.003), mPAP/CO slope r=0.458 (p 0.012). Peak exercise TAPSE/sPAP showed an AUC=0.85 (CI95% 0.70-1.00, fig. 1), and a cutoff point of &amp;lt;0.52 mm/mmHg, showed a S 80% / E 93% PPV 92% and NPV 81%, to predict an abnormal response. The echo derived mPAP/CO slope showed an AUC=0.78 (CI95% 0.59-0.96), and a cutoff point of &amp;gt; 2.44 mmHg·L−1·min−1 showed a S and E of 85% and 67% PPV 71 % and NPV of 83% to predict ex-PH. Abnormal septal motion at peak exercise showed a S 90%, E 78%, PPV 71% and NPV of 93% to predict ex-PH. Conclusions In our study cohort, up to 45% of symptomatic patients with persistent pulmonary thrombosis after a PE, without relevant PH at rest, developed ex-PH. New echo-derived parameters such as TAPSE/sPAP, a surrogate RV-PA coupling parameter, and echo-mPAP/CO slope, showed a good performance to predict an abnormal hemodynamic response. Ex-echo, feasible, non invasive and widely available, might represent a useful tool for the selection of patients for invasive hemodynamic workup.Peak exercise TAPSE/sPAP ROC curveTable 1

Resting RV-PA uncoupling as predictor of exercise induced pulmonary hypertension in patients with chronic thromboembolic pulmonary disease

Abstract Background and aim Chronic thromboembolic disease (CTED) refers to the presence of chronic thrombotic pulmonary vascular occlusion in the absence of pulmonary hypertension (PH) at rest but with exercise limitation caused by established vasculopathy. Symptoms after an acute pulmonary embolism (PE) with persistent lung perfusion defects need a complete diagnostic approach. Screening these symptomatic patients with resting echocardiography (echo) is challenging. The aim of this study is to analyze the echocardiographic predictors at rest of exercise induced PH (ex-PH) in patients with suspected CTED. Methods Symptomatic patients with confirmed perfusion defects in lung V/Q scintigraphy despite optimal anticoagulant therapy for at least 3 months after an acute PE were selected. Structural heart disease or pulmonary disease were excluded. Relevant PH at rest was ruled-out (mPAP &amp;lt;25 mmHg, PVR &amp;lt;3 Wu, PAWP &amp;lt;15 mmHg according to available definition at the time). A right heart catheterization with incremental exercise protocol (cycle ergometer), and simultaneous transthoracic echo were performed. Hemodynamic and echo parameters were collected at each exercise level. A mPAP/CO slope &amp;gt;3 mmHg·L−1·min−1 was considered an abnormal hemodynamic response to exercise. Right V-PA coupling was estimated as TAPSE/sPAP and RV free wall global longitudinal strain (RV-GLS)/sPSP ratios. Results 31 patients (32% women, mean age 51.8 ± 14.7 y) were included. Fourteen patients (45%) developed ex-PH. Baseline characteristics according to invasive hemodynamic response are shown in Table 1. Resting RV function (TAPSE and RV-GLS), but not size, was significatively impaired in the ex-PH cohort. Resting echo sPAP or TR max velocity did not achieve any difference between groups, although invasive sPAP did. Resting TAPSE/sPAP and RV-GLS/sPAP were significantly reduced in the ex-PH group. In ROC curve, resting TAPSE/sPAP showed an AUC 0.75 (CI 95% 0.56-0.95) to predict ex- PH. A cutoff point of &amp;lt;0.62 mm/mmHg at rest, showed a S 88% / E 71%, PPV 78.9 % and NPV 83.3%. Resting RV-GLS/sPAP ratio showed an AUC 0.859 (CI 95% 0.708 – 0.990) to predict ex- PH. A cutoff point of &amp;gt; - 0.67 %/mmHg, showed a S 75.0% / E 87.5%, PPV 78.2 % and NPV 82.4%. to predict ex- PH. Conclusions Exercise limitation appears to be attributable to ex-PH in up to 45% of symptomatic patients with persistent pulmonary thrombosis after a PE without relevant PH at rest. Echo derived parameters at rest, surrogates of RV-PA uncoupling, such as TAPSE/sPAP and RV-GLS/sPAP, could be of great interest to identify patients with abnormal hemodynamic response to exercise, and help in the initial non invasive diagnostic workup of these increasingly group of patients.ROC curvesTable 1Resting Echo values

COMPLICATIONS OF CARDIOPULMONARY EXERCISE TESTING

COMPLICATIONS OF CARDIOPULMONARY EXERCISE TESTING

Feasibility of critical care ergometry: Exercise data of patients on mechanical ventilation analyzed as nine-panel plots.

Nine‐panel plots are standard displays of cardiopulmonary exercise data, used in cardiac and pulmonary medicine to investigate the nature of exercise limitation. We explored whether this approach could be used to analyze the data of critically ill patients on mechanical ventilation, capable of exercising actively. Patients followed an incremental exercise protocol using a bedside cycle ergometer. Respiratory gases were analyzed using indirect calorimetry, and blood gases were sampled from arterial catheters. Data of seven patients were combined into nine‐panel plots. Systematic analysis clarified the nature of exercise limitation in six cases. Resting metabolic rate was increased in all patients, with a median oxygen uptake (V˙O2) of 5.52 (IQR 4.29–6.31) ml/kg/min. Unloaded cycling increased the V˙O2 by 19.8% to 6.61 (IQR 5.99–7.08) ml/kg/min. Adding load to the ergometer increased the V˙O2 by another 20.0% to reach V˙O2peak at a median of 7.14 (IQR 6.67–10.75) ml/kg/min, corresponding to a median extrinsic workload of 7 W. This was accompanied by increased CO2 production, respiratory minute volume, heart rate, and oxygen pulse. Three patients increased their V˙O2 to >40% of predicted V˙O2max, two patients passed the anaerobic threshold. Dead space ventilation was 44%, decreasing to 42% and accompanied by lower ventilatory equivalents during exercise. Exercise produced no net change in alveolo‐arterial PO2 difference. We concluded that diagnostic ergometry in mechanically ventilated patients was feasible. Analysis of the data as nine‐panel plots provided insight into individual limitations to exercise.

In-vivo quantification of lactate using Near Infrared reflectance spectroscopy.

Elevated lactate levels in blood (hyperlactatemia) are indications of hypoperfusion or sepsis in critical care conditions. Quantification and monitoring of this important marker is performed using intermittent blood sampling, which fails to provide a complete scenario to aid clinicians in diagnosis. The feasibility of Near Infrared (NIR) Spectroscopy as an alternative to state-of-the-art techniques in critical care environments for non-invasive and continuous monitoring of lactate has previously been established. Nevertheless, the challenge lies in translating this research from bench to bedside monitoring. For this reason, a pilot investigation was carried out with a portable NIR spectrometer, where spectra in the range of 900-1300 nm were collected from 8 healthy human volunteers undertaking a high intensity incremental exercise protocol for lactate monitoring. This paper reports on the measurement set-up, spectra acquisition and analysis of diffuse NIR reflectance spectra of varying concentrations of lactate. The results obtained by 2D correlation analysis and linear regression are promising and show that the wavelengths 923 nm, 1047 nm, 1142 nm, 1233 nm, 1280 nm and 1330 nm are significant for lactate concentration determination in the NIR region. This provides the necessary confidence for using NIR sensor technology for lactate detection in critical care.

The Impact of Moderate and High Intensity Cardiovascular Exertion on Sub-Elite Soccer Referee's Cognitive Performance: A Lab-Based Study.

Soccer referees represent a specialized population who are required to perform decisional or perceptual tasks during physical exertion. Recent studies have demonstrated that submaximal acute exercise has a positive impact on cognitive performance. However, less is known about the impact of more strenuous exertion on cognitive performance. This study assessed the effect of moderate and maximal intensity exercise exertion on a cognitive performance in sub-elite soccer referees. Twelve experienced soccer referees (4 female, 8 male) were recruited. Data were collected on 2 separate days. Baseline fitness level was assessed by a standardized aerobic capacity test (VO2max Test) on Day 1, along with practice trials of the Stroop Color Word Test (Stroop Test) for evaluating cognitive performance. On Day 2, cognitive performance was assessed before, during, and after an incremental intensity exercise protocol based on the Fédération International de Football Association (FIFA) referee fitness test. Relative to results obtained at rest performance on the Stroop Test improved at moderate exertion and at maximal exertion during the modified FIFA fitness test (F = 18.97, p = .005). Mean time to completion (in seconds) of the interference Stroop task significantly improved (p < .05) between rest and moderate exertion [-3.0 ± 3.0 seconds] and between rest and maximal exertion [-4.8 ± 2.6 seconds]. In summary, we observed that cognitive performance was found to improve when sub-elite soccer referees performed moderate and maximal exercise relative to results obtained at rest. It is possible that referees focus their attention to improve goal-oriented processing in the brain during physical exertion.

Six weeks of high intensity interval training (HIIT) facilitates a four year preservation of aerobic capacity in sedentary older males: A reunion study.

Long-term implications of acutely increased cardiorespiratory fitness following short-term exercise interventions in older adults are unknown. In this study, we examined peak oxygen uptake (VO2peak) after 4-years of 'free-living' after a high intensity interval training (HIIT) intervention. Seventeen lifelong exercisers (LEX) and 17 previously sedentary (SED) males (55-74years of age in 2012) were tested four years (phase D) after our previous experiment which included 6-weeks of aerobic moderate intensity exercise (phase B), followed by 6-weeks of HIIT (phase C). At all stages, a standard incremental exercise protocol on a cycle ergometer was completed to determine VO2peak. SED (P=1.000, Cohen's d=0.01) and LEX (P=1.000, Cohen's d=0.11) VO2peak at phase D was not different from phase A (enrolment). SED experienced a large decrease in VO2peak from phase C to phase D (32±6ml·kg·min-1 to 27±6ml·kg·min-1 [P<0.001, Cohen's d=0.81]). LEX experienced a small decrease in VO2peak from phase C to phase D (42±7ml·kg·min-1 to 39±9ml·kg·min-1 [P<0.001, Cohen's d=0.46]). At phase D, LEX had greater VO2peak than SED (P<0.001, Cohen's d=1.73). The proportion of subjects who reported discontinuing training, maintaining moderate training, and maintaining HIIT differed between groups (P=0.023), with LEX self-reporting more HIIT, and SED self-reporting more discontinuation from exercise. Those who continued exercising experienced a reduction in VO2peak over the four years from 39±7ml·kg·min-1 to 36±9ml·kg·min-1 (N=25, P<0.001, Cohen's d=0.37), and those who discontinued exercising also experienced a reduction in VO2peak from 30±7ml·kg·min-1 to 25±9ml·kg·min-1 (N=9, P=0.003, Cohen's d=0.62). Four years after completing a brief period of aerobic exercise and HIIT, older males demonstrated a preservation of VO2peak, irrespective of training status (LEX or SED). However, LEX exhibited greater VO2peak than SED after 4-years of unsupervised 'free-living'. Notably, participants who discontinued exercising experienced a greater reduction in VO2peak. These data suggest that a 6weeks of supervised HIIT can facilitate the long term.

Functional Outcomes of Arthroscopic Partial Meniscectomy Versus Physical Therapy for Degenerative Meniscal Tears Using a Patient-Specific Score: A Randomized Controlled Trial.

Background:It is unknown whether the treatment effects of partial meniscectomy and physical therapy differ when focusing on activities most valued by patients with degenerative meniscal tears.Purpose:To compare partial meniscectomy with physical therapy in patients with a degenerative meniscal tear, focusing on patients’ most important functional limitations as the outcome.Study Design:Randomized controlled trial; Level of evidence, 1.Methods:This study is part of the Cost-effectiveness of Early Surgery versus Conservative Treatment with Optional Delayed Meniscectomy for Patients over 45 years with non-obstructive meniscal tears (ESCAPE) trial, a multicenter noninferiority randomized controlled trial conducted in 9 orthopaedic hospital departments in the Netherlands. The ESCAPE trial included 321 patients aged between 45 and 70 years with a symptomatic, magnetic resonance imaging–confirmed meniscal tear. Exclusion criteria were severe osteoarthritis, body mass index >35 kg/m2, locking of the knee, and prior knee surgery or knee instability due to an anterior or posterior cruciate ligament rupture. This study compared partial meniscectomy with physical therapy consisting of a supervised incremental exercise protocol of 16 sessions over 8 weeks. The main outcome measure was the Dutch-language equivalent of the Patient-Specific Functional Scale (PSFS), a secondary outcome measure of the ESCAPE trial. We used crude and adjusted linear mixed-model analyses to reveal the between-group differences over 24 months. We calculated the minimal important change for the PSFS using an anchor-based method.Results:After 24 months, 286 patients completed the follow-up. The partial meniscectomy group (n = 139) improved on the PSFS by a mean of 4.8 ± 2.6 points (from 6.8 ± 1.9 to 2.0 ± 2.2), and the physical therapy group (n = 147) improved by a mean of 4.0 ± 3.1 points (from 6.7 ± 2.0 to 2.7 ± 2.5). The crude overall between-group difference showed a –0.6-point difference (95% CI, –1.0 to –0.2; P = .004) in favor of the partial meniscectomy group. This improvement was statistically significant but not clinically meaningful, as the calculated minimal important change was 2.5 points on an 11-point scale.Conclusion:Both interventions were associated with a clinically meaningful improvement regarding patients’ most important functional limitations. Although partial meniscectomy was associated with a statistically larger improvement at some follow-up time points, the difference compared with physical therapy was small and clinically not meaningful at any follow-up time point.Registration:NCT01850719 (ClinicalTrials.gov identifier) and NTR3908 (the Netherlands Trial Register).

Progress Update and Challenges on O2max Testing and Interpretation.

The maximal oxygen uptake (O2max) is the primary determinant of endurance performance in heterogeneous populations and has predictive value for clinical outcomes and all-cause mortality. Accurate and precise measurement of O2max requires the adherence to quality control procedures, including combustion testing and the use of standardized incremental exercise protocols with a verification phase preceded by an adequate familiarization. The data averaging strategy employed to calculate the O2max from the breath-by-breath data can change the O2max value by 4–10%. The lower the number of breaths or smaller the number of seconds included in the averaging block, the higher the calculated O2max value with this effect being more prominent in untrained subjects. Smaller averaging strategies in number of breaths or seconds (less than 30 breaths or seconds) facilitate the identification of the plateau phenomenon without reducing the reliability of the measurements. When employing metabolic carts, averaging intervals including 15–20 breaths or seconds are preferable as a compromise between capturing the true O2max and identifying the plateau. In training studies, clinical interventions and meta-analysis, reporting of O2max in absolute values and inclusion of protocols and the averaging strategies arise as imperative to permit adequate comparisons. Newly developed correction equations can be used to normalize O2max to similar averaging strategies. A lack of improvement of O2max with training does not mean that the training program has elicited no adaptations, since peak cardiac output and mitochondrial oxidative capacity may be increased without changes in O2max.

Metabolic Cost of Paddling on Different Commercially Available Kayak Ergometers.

To comparethe metabolic cost of paddling on different commercially available kayak ergometers using a standardized kayak incremental exercise protocol. Six male sprint kayak athletes undertook an incremental exercise protocol on 3 different kayak ergometers utilizing a randomized counterbalanced pair-matched design. Mean maximal aerobic power on the WEBA ergometer (265 [14]W) was significantly higher than on the Dansprint (238 [9]W) and KayakPro® (247 [21]W, P < .01, effect size [ES] = 0.80). At the fifth stage, absolute oxygen consumption on the WEBA (3.82 [0.25]L·min-1) was significantly lower (P < 0.05, ES = 0.20) than KayakProand Dansprint (4.10 [0.28] and 4.08 [0.27]L·min-1, respectively). Blood lactate concentration response at the sixth stage was significantly lower for the WEBA (3.5 [0.8]mmol·L-1), compared with KayakProand Dansprint (5.4 [1.2] and 5.6 [1.5] mmol·L-1, P = .012, ES = 0.20). Stroke rate was significantly higher, without any effect of pacing during the submaximal stages for the Dansprint, compared with the WEBA (P < .001, ES = 0.28) and KayakPro(P < .001, ES = 0.38). A pacing effect was present at the maximal stage for all ergometers. This study demonstrated that paddling on different kayak ergometers when controlling power output elicits different metabolic and work outputs. It is recommended that scientists and coaches avoid testing on different ergometers and regularly calibrate these devices. Moreover, when an ergometer has been calibrated against a first principle device, it is necessary to consider calibration of various drag settings, due to their impact on stroke rate. Further research should explore the relationship between drag settings and stroke rate.

The Accuracy Of Heart Rate Monitors And Determination Of Heart Rate Percentages At Anaerobic Threshold

PURPOSE: To examine the heart rate percentage (HR%) at the Anaerobic Threshold (AT) in order to determine the appropriate exercise intensity below or above the AT. A second goal was to assess the accuracy of different types of wearable heart rate monitors (HRMs) during a graded exercise test. METHODS: Thirty healthy individuals (n=21 male & n=9 female; aged 24.5 ± 3.5 years) participated in a single incremental exercise protocol on a cycle ergometer (CE). AT was detected through a metabolic cart by using V-slope method, which determined the point of a nonlinear increase in carbon dioxide output (VCO2) against oxygen uptake (VO2). HR was measured each minute of exercise test via two optical-based monitors (Cellular Watch [IW] & Fitness tracker [FB]) and two electrical-based monitors (traditional monitor [ECG] & heart rate monitor [PL]). Electrocardiography (ECG) was used as a “Gold Standard” for comparison in this study. RESULTS: AT was reached at the mean and standard deviation (SD) of 130 ± 16 bpm. HR% at AT was observed 67 ± 8 % of HRpeak, Heart Rate Reserve Percentages (HRR%) at AT were observed at 42 ± 15 % of HRpeak. Across all exercise testing stages (Stage 1 [S1], Stage 2 [S2], Stage 3 [S3], etc.), no significant differences were found in HR values between ECG and PL. The most statistical differences were found in HR between ECG and IW, (S5=[p=0.018], S6=[p=0.041] and S7=[p=.005], respectively). As intensity increased, FB and IW underestimated the HR values throughout all stages when compared with the ECG. CONCLUSIONS: Analysis of HR% at AT was estimated at approximately 67% of participant maximum effort as well as HRR% at AT was estimated at 42%. At the light-intensity, accurate outcomes of HR values were observed from all wearable HRMs. However, with increased intensity, the accuracy of wearable devices was varied at moderate and high-intensity exercise testing. The PL had the greatest agreement with ECG when compared to other devices. This might be due to the fact that both HRMs utilize a similar mechanism of measurement. The electrical-based HRM was found to be more accurate in comparison to the optical-based HRMs.

Consumer-grade biosensor validation for examining stress in healthcare professionals.

IntroductionA high prevalence of stress and burnout has been reported among healthcare professionals; however, the current tools utilized to quantify such metrics are not in keeping with doctors’ busy lifestyles, and moreover do not comply with infection prevention policies. Given that increased stress can subsequently impact both the healthcare profession and the patient in care, this study aimed to assess the validity of a wearable biosensor to monitor and manage stress experienced by healthcare professionals.MethodsIn all, 12 healthy, male volunteers completed an incremental exercise protocol to volitional exhaustion, which aimed to induce physiological stress in a graded manner. A wearable consumer‐grade biosensor (Vital Scout, VivaLNK, Inc.) was used to measure stress, energy expenditure, respiration rate, and activity throughout the exercise protocol. These variables were validated against online breath‐by‐breath analysis (MedGraphics Ultima Series).ResultsWhen compared against online “gold standard” measurements, the Vital Scout biosensor demonstrated a high level of accuracy to measure energy expenditure (r = .776, p < .001) and respiration rate (r = .744, p < .001). The V˙O2 increase observed during the incremental exercise test was associated with the Vital Scout biosensor's measurement of activity (r = .777, p < .001). In contrast, there was a poor relationship between the changes in V˙O2 and the Vital Scout biosensor's ability to detect stress (r = −.195, p = .013).ConclusionThe Vital Scout biosensor provided an accurate assessment of energy expenditure and respiration when compared to the “gold standard” assessment of these parameters. Biosensors have the potential to measure stress and deserve further research in the peri‐hospital environment.

Diagnostic Validity of Cardiopulmonary Exercise Testing for Screening Pulmonary Hypertension in Patients With Chronic Obstructive Pulmonary Disease.

To determine diagnostic validity of cardiopulmonary exercise testing (CPX) parameters for detecting pulmonary hypertension (PH) in patients with chronic obstructive pulmonary disease (COPD) and to investigate association between CPX parameters and indices of PH. This cross-sectional study enrolled 48 moderate to very severe COPD patients in whom PH was confirmed by echocardiography. Symptom-limited CPX was performed using an incremental exercise protocol. Relevant CPX parameters were derived and were tested for their diagnostic ability for diagnosing PH. Logistic regression was applied to examine the effect of various clinical covariates on the diagnostic ability of exercise test variables for detecting PH. Of the 48 patients, 29 were diagnosed with PH and 19 were negative for PH based on echocardiographic testing. CPX measures including peak oxygen uptake (% predicted (Equation is included in full-text article.)O2peak, (Equation is included in full-text article.)O2peak [mL/min], (Equation is included in full-text article.)O2/kg), oxygen pulse ((Equation is included in full-text article.)O2/HR % predicted, (Equation is included in full-text article.)O2/HR mL/beat), and peak minute ventilation ((Equation is included in full-text article.)Epeak [L/m]) were inversely correlated with mean pulmonary arterial pressure (mPAP). Peak (Equation is included in full-text article.)O2/HR and (Equation is included in full-text article.)O2peak were found to be significant predictors of PH in univariate analysis. (Equation is included in full-text article.)O2peak (%), (Equation is included in full-text article.)O2/HR (mL/beat), and desaturation (%) were identified as independent predictors of PH adjusted for age, forced expiratory volume in 1 sec (%), and forced vital capacity (L). The present study validates the use of CPX parameters such as (Equation is included in full-text article.)O2peak and (Equation is included in full-text article.)O2/HR as a diagnostic tool for correctly identifying PH in COPD patients. Therefore, CPX may be used as an adjunct to echocardiographic measurement of PH where there is unavailability of equipment and expertise.

Effects of Oral Branched-Chain Amino Acids (BCAAs) Intake on Muscular and Central Fatigue During an Incremental Exercise.

The aim of this study was to investigate the effects of oral branched-chain amino acids (BCAAs) intake on muscular (creatine kinase and myoglobin) and central (serotonin) fatigue during an incremental exercise protocol and to determine the time to exhaustion. Sixteen male long-distance runners (25.7 ± 2.0 yrs) performed two trials, 14 days apart. Using a double-blind, placebo-controlled, randomised crossover design, participants ingested either 20 g of BCAAs (BCAA trial) or a placebo 1 hour prior to performing an incremental exercise session on a treadmill. The starting speed was 8 km/h and this was increased by 1 km/h every 5 minutes until volitional exhaustion. Blood analysis indicated that plasma levels of serotonin were lower in the BCAA trial (259.3 ± 13.5 ng/ml) than the placebo trial (289.1 ± 14.5 ng/ml) (p < 0.05). There was a similar pattern of results for free fatty acid (p < 0.05). The creatine kinase level was higher in the BCAA trial (346.1 ± 33.7 U/L) than the placebo trial (307.3 ± 30.2 U/L). No significant difference between trials was observed regarding the level of myoglobin (p = 0.139). Time to exhaustion was longer in the BCAA trial (50.4 ± 2.3 min) than the placebo trial (46.6 ± 3.2 min). In conclusion, oral intake of 20 g of BCAAs 1 hour prior to an incremental treadmill exercise session increased time to exhaustion, probably due to the reduction in serotonin concentration. As myoglobin levels were within the normal range in both trials, we conclude that the participants did not reach muscular fatigue.