BACKGROUND Resting cardiac function does not necessarily affect exercise capacity. However, to determine whether it affects early dynamics of oxygen uptake (VO2) during exercise, we measured VO2 during a constant work rate and during incremental exercise testing in patients with a history of myocardial infarction. VO2 kinetics and exercise capacity were compared between patients with relatively...

BACKGROUND The authors have developed a new clinical bymixer that bypasses a constant fraction of gas flow through a mixing arm. A separate bymixer was interposed in the expiratory and inspiratory limbs of the ventilation circuit to measure mixed gas fractions. By utilizing nitrogen conservation, the clinical bymixer allows the determination of airway carbon dioxide elimination (VCO2) and oxyge...

We studied the possibility of predicting PaO2 during exercise of a given oxygen uptake (VO2) from resting pulmonary function tests (PFTs) in patients with chronic obstructive pulmonary disease (COPD). The three-minute incremental treadmill exercise was performed with serial measurements of PaO2 via intra-arterial catheter in 46 patients (mean FEV1 = 1.09 +/- 0.49L, mean FEV1/FVC = 44 +/- 15 per...

The primary objective of this study was to assess the efficacy of measuring both aerobic and anaerobic power in a 60-second, maximal effort test. It was hypothesized that oxygen consumption increases rapidly during maximal effort and maximal oxygen consumption (VO2 max) may be reached in one minute. Fifteen United States Cycling Federation competitive cyclists performed the following tests: 1) ...

OBJECTIVES We sought to study the effects of catecholamines on myocardial oxygen consumption (VO2), regional blood flows and total body VO2 in lambs with circulatory congestion. BACKGROUND Catecholamines are often used to support cardiovascular function in children with circulatory congestion because they increase contractility as well as heart rate. However, these changes increase myocardial...

Some second-generation antipsychotics (SGAs) increase insulin resistance and fat oxidation, but counter intuitively they do not activate lipolysis. This seems unsustainable for meeting energy demands. Here, we measured dose-dependent effects of SGAs on rates of oxygen consumption (VO2), respiratory exchange ratio (RER), and physical activity in C57BL/6J mice. The role of H1-histamine receptors ...

PURPOSE This study aimed to investigate whether cardiac output (CO) responses were related to VO2 kinetics during cycling in type 2 diabetes. METHODS A total of 9 middle-aged women with uncomplicated type 2 diabetes, 9 nondiabetic overweight women, and 11 nondiabetic lean women were recruited. Initially, the ventilatory threshold (VT) and peak VO2 were determined during a maximal graded test....

BACKGROUND Exercise testing with ventilatory expired gas analysis has proven to be a valuable tool for assessing patients with heart failure (HF). Peak oxygen consumption (peak VO2) continues to be considered the gold standard for assessing prognosis in HF. The minute ventilation--carbon dioxide production relationship (VE/VCO2 slope) has recently demonstrated prognostic significance in patient...

BACKGROUND The Wellness-Fitness Initiative submaximal treadmill exercise test (WFI-TM) is recommended by the US National Fire Protection Agency to assess aerobic capacity (VO2 max) in firefighters. However, predicting VO2 max from submaximal tests can result in errors leading to erroneous conclusions about fitness. AIMS To investigate the level of agreement between VO2 max predicted from the ...

Dynamic body acceleration (DBA) has been used as a proxy for energy expenditure in logger-equipped animals, with researchers summing the acceleration (overall dynamic body acceleration--ODBA) from the three orthogonal axes of devices. The vector of the dynamic body acceleration (VeDBA) may be a better proxy so this study compared ODBA and VeDBA as proxies for rate of oxygen consumption using hu...