Respiratory Determinants of Exercise Limitation

Assessing Exercise Limitation Using Cardiopulmonary Exercise Testing

The cardiopulmonary exercise test (CPET) is an important physiological investigation that can aid clinicians in their evaluation of exercise intolerance and dyspnea. Maximal oxygen consumption ([Formula: see text]) is the gold-standard measure of aerobic fitness and is determined by the variables that define oxygen delivery in the Fick equation ([Formula: see text] = cardiac output × arterial-v...

Respiratory muscle dynamics and control during exercise with externally imposed expiratory flow limitation.

To determine how decreasing velocity of shortening (U) of expiratory muscles affects breathing during exercise, six normal men performed incremental exercise with externally imposed expiratory flow limitation (EFLe) at approximately 1 l/s. We measured volumes of chest wall, lung- and diaphragm-apposed rib cage (Vrc,p and Vrc,a, respectively), and abdomen (Vab) by optoelectronic plethysmography;...

Respiratory muscle dysfunction and exercise limitation in patients with moderate adolescent idiopathic scoliosis

Materials and methods Case-control study in with 85 patients with AIS and 25 healthy volunteers. AIS patients were classified into two groups determined by the curve mangitude): A (Cobb angle 25-40°) and B (Cobb angle >40°). Main outcomes were: respiratory muscle strength estimated by maximal inspiratory and expiratory preassures (MIP, MEP), peripherical muscle strength assessed in hands and lo...

Respiratory effort sensation during exercise with induced expiratory-flow limitation in healthy humans.

Nine healthy subjects (age 31 +/- 4 yr) exercised with and without expiratory-flow limitation (maximal flow approximately 1 l/s). We monitored flow, end-tidal PCO2, esophageal (Pes) and gastric pressures, changes in end-expiratory lung volume, and perception (sensation) of difficulty in breathing. Subjects cycled at increasing intensity (+25 W/30 s) until symptom limitation. During the flow-lim...

Exercise Limitation following Extensive Pulmonary Resection.