To validate VO2 and energy expenditure predictions by the Suunto heart rate (HR) system against a first principle gas analysis system, well-trained male (n = 10, age 29.8 +/- 4.3 years, VO2 65.9 +/- 9.7 ml x kg x min) and female (n = 7, 25.6 +/- 3.6 years, 57.0 +/- 4.2 ml x kg x min) runners completed a 2-stage incremental running test to establish submaximal and maximal oxygen uptake values. M...

OBJECTIVE To assess the safety and efficacy of unsupervised rehabilitation (USR) in the long run in low-risk patients with coronary artery disease. METHODS We carried out a retrospective study with 30 patients divided into: group I (GI) - 15 patients from private clinics undergoing unsupervised rehabilitation; group II (GII) - control group, 15 patients from ambulatory clinic basis, paired by...

PURPOSE Develop an MRI method to estimate skeletal muscle oxygen consumption (VO2 ) with dynamic exercise using simultaneous measurement of venous blood flow (VBF) and venous oxygen saturation (SvO2 ). METHODS Real-time imaging of femoral VBF using a complex-difference method was interleaved with imaging of venous hemoglobin oxygen saturation (SvO2 ) using magnetic susceptometry to estimate m...

To determine whether the levels of oxygen consumption (VO2) required to relieve an existing oxygen debt are variable, increases in VO2 produced by increases in oxygen delivery (DO2) were evaluated longitudinally in septic patients with lactic acidosis and related to changes in lactate levels. Interventions were performed in 17 patients and consisted of fluid administration (n = 11), packed red ...

To assess the relation between increases in contractile function and oxygen consumption (Vo2) during increased coronary flow (Gregg's phenomenon), we measured the end-systolic pressurevolume relation and the relation between Vo2 and left ventricular systolic pressure-volume area (PVA, a measure of total mechanical energy output) in blood-perfused, isovolumically contracting rabbit hearts during...

Recent studies have shown that myocardial oxygen consumption does not proportionally decrease with the deterioration of contractile function in stunned myocardium. To investigate this disproportion, we studied the end-systolic pressure-volume relation and the relation between oxygen consumption per beat (VO2) and systolic pressure-volume area (PVA, a measure of total mechanical energy) in stunn...

OBJECTIVES This study explores whether cardiovascular fitness levels and senescent decline are similar in the Tsimane of Bolivia and Canadians, as well as other subsistence and industrialized populations. Among Tsimane, we examine whether morbidity predicts lower levels and faster decline of cardiovascular fitness, or whether their lifestyle (e.g., high physical activity) promotes high levels a...

There is much interest in the relationship between oxygen delivery and oxygen consumption in the critically ill patient. This interest is occasioned by the observation that patients with sepsis and the adult respiratory distress syndrome have a linear or "supply-dependent" relationship instead of the normally observed biphasic or "supply-independent" relationship. These relationships are only v...

We questioned whether the decrease in O2 consumption (VO2) during hypoxia in newborns is a regulated response or reflects a limitation in O2 availability. Experiments were conducted on previously instrumented conscious newborn dogs. VO2 was measured at a warm ambient temperature (30 degrees C, n = 7) or in the cold (20 degrees C, n = 6), while the animals breathed air or were sequentially expos...