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Pathophysiological basis, evaluation and rationale of exercise training
Published in Claudio F. Donner, Nicolino Ambrosino, Roger S. Goldstein, Pulmonary Rehabilitation, 2020
Pierantonio Laveneziana, Paolo Palange
Briefly, two variables are used to detect exercise intolerance. observed during the exercise test can be compared to normal values (25). , though, has the disadvantage that it is dependent on motivation as well as physiological capacity. The anaerobic/ventilatory threshold (AT), determined from gas exchange or measurements of blood lactate, defines the point at which lactate production exceeds lactate elimination; above this point exercise cannot be performed without reliance on anaerobic energy sources (3,11–14). It has the advantage of being effort independent but relies on pattern recognition for accurate detection.
Lifestyle Medicine Clinical Processes
Published in James M. Rippe, Lifestyle Medicine, 2019
Ventilatory threshold testing may provide a useful tool for measuring cardiorespiratory fitness, using the concept that as exercise intensity increases, ventilation increases in a somewhat linear manner, demonstrating deflection points at certain intensities associated with metabolic changes within the body. The first ventilatory threshold, VT1, or the “crossover point,” represents a level of intensity at which the blood lactate accumulates faster than it can be cleared, which causes the person to breathe faster in an effort to blow off the extra carbon dioxide. In trained individuals, VT1 represents the highest intensity of exercise that can be sustained for one to two hours of exercise. Applying a submaximal talk test identifies the heart rate (HR) that can be used as a target HR to determine exercise intensity. For those interested in health and general fitness, staying at or slightly below this intensity would be recommended in the initial fitness programming.
Respiratory system during a progressive work test
Published in Robert B. Schoene, H. Thomas Robertson, Making Sense of Exercise Testing, 2018
Robert B. Schoene, H. Thomas Robertson
Clinical interpretation of a progressive work test requires the identification of the time during a test when the metabolic acidosis of exercise becomes manifest, the point described as the ventilatory (or anaerobic) threshold. This point can be identified by examination of the CPET measurements of ventilation and gas exchange. The increase in arterial lactate concentrations during the final stages of a CPET reflects the onset of muscle norepinephrine release and glycolysis in the heavily exercising muscles, with the associated metabolic acidosis and supplemental ATP production. As noted in the muscle chapter, the beginning of this metabolic acidosis could be best identified during a CPET with multiple arterial blood samples drawn for lactate concentrations. However a ventilatory threshold can ordinarily be identified noninvasively by the onset of an additional increase in exercise ventilation, hence the term ventilatory threshold. There are three CPET measurements that assist in the identification of the exercise ventilatory threshold, and ordinarily all three should be considered for a best consensus estimate (Figure 5.10).
Cardiorespiratory fitness in women after severe pre-eclampsia
Published in Hypertension in Pregnancy, 2023
Lasse Gronningsaeter, Mette-Elise Estensen, Helge Skulstad, Eldrid Langesaeter, Elisabeth Edvardsen
Being overweight was defined as a body mass index (BMI) ≥ 25 kg∙m−2, and obesity was defined as BMI ≥30 kg∙m−2, according to the World Health Organization (WHO) classification (27). The predicted values for spirometry were calculated using the Global Lung Function Initiative equations (28,29). The highest VO2 sampled over 30 s was defined as VO2peak. Reference values for VO2peak values were used from a large Norwegian population of 759 healthy adults who successfully completed CPET using the same treadmill protocol as in the present study (20). Low CRF was defined as VO2peak <85% of that predicted (30). Ventilatory threshold was determined by the ventilatory equivalent method. A ventilatory limitation was defined as a breathing reserve ≤ 15% or 11 L∙min−1, and a gas exchange limitation was defined as a VE/VCO2 slope ≥ 34 (31). CPET end criteria defining maximal effort were respiratory exchange ratio (RER ≥1.10) or RPE on Borg scale6–20 ≥17 (22).
Effects of Concurrent Training and a Multi-Ingredient Performance Supplement Containing Rhodiola rosea and Cordyceps sinensis on Body Composition, Performance, and Health in Active Men
Published in Journal of Dietary Supplements, 2021
Vince C. Kreipke, PhD, Robert J. Moffatt, PhD, Charles J. Tanner, MA, Michael J. Ormsbee, PhD
In the present study, MIPS did not influence lactate threshold. This supports previous research suggesting that these ingredients may not affect markers of lactate production (De Bock et al. 2004; Earnest et al. 2004; Noreen et al. 2013; Duncan et al. 2015). However, not all studies agree (Chen et al. 2010; Hirsch et al. 2017). An animal model in previous research (Kumar et al. 2011) demonstrated that chronic supplementation with CS significantly increased MCT1 protein expression in red gastrocnemius muscle. This finding lead researchers to speculate these increases translate into increased lactate transport, resulting in improved aerobic performance. However, our results do not support this change in lactate threshold, which concurs with the bulk of the existing research. These differences may be due to differences in methodologies. The current research focused on the advancement of “stages” in intensity as opposed to potentially more sensitive testing methodologies such as ventilatory threshold testing methodologies.
Observations on changes in ventricular repolarization following four weeks of exercise training in chronic heart failure patients
Published in Scandinavian Cardiovascular Journal, 2020
Maxime Caru, Hugo Gravel, Atul Pathak, Marc Bousquet, Michel Galinier, Vincent Jacquemet, Daniel Curnier
The test, performed on an electromagnetic cycle ergometer (Ergoline 900, Bunik, Netherland), consisted of a warm-up at 20% of the individual’s predicted maximal power (depending on age, gender, weight and height [10]), followed by a 10% increase of the load every 1-min; until maximal exertion as perceived by the patient. Maximal oxygen uptake (2 peak) were measured with a breath-by-breath system calibrated prior to each test (CardiO2; Medical Graphic Corp, St Paul, MN) and VO2 peak was defined as the maximal 20-s average VO2. Blood pressure was measured every 2 min and a twelve-lead ECG was obtained continuously. Tests were validated as maximal when meeting at least two of the three following criteria: maximal respiratory exchange ratio >1.15; HRmax ≥85% of the predicted value; maximal perceived exertion >7/10 [11]. Ventilatory threshold was visually determined by two independent physiologists as the point of the incremental exercise at which ventilation (VE/2) increased without a concomitant change in the ventilatory equivalent for CO2 (VE/VCO2).