کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2903972 1173401 2008 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Update in the Understanding of Respiratory Limitations to Exercise Performance in Fit, Active Adults
موضوعات مرتبط
علوم پزشکی و سلامت پزشکی و دندانپزشکی کاردیولوژی و پزشکی قلب و عروق
پیش نمایش صفحه اول مقاله
Update in the Understanding of Respiratory Limitations to Exercise Performance in Fit, Active Adults
چکیده انگلیسی

This review addresses three types of causes of respiratory system limitations to O2 transport and exercise performance that are experienced by significant numbers of active, highly fit younger and older adults. First, flow limitation in intrathoracic airways may occur during exercise because of narrowed, hyperactive airways or secondary to excessive ventilatory demands superimposed on a normal maximum flow-volume envelope. Narrowing of the extrathoracic, upper airway also occurs in some athletes at very high flow rates during heavy exercise. Examination of the breath-by-breath tidal flow-volume loop during exercise is key to a noninvasive diagnosis of flow limitation and to differentiation between intrathoracic and extrathoracic airway narrowing. Second exercise-induced arterial hypoxemia occurs secondary to an excessively widened alveolar-arterial oxygen pressure difference. This inefficient gas exchange may be attributable in part to small intracardiac or intrapulmonary shunts of deoxygenated mixed venous blood during exercise. The existence of these shunts at rest and during exercise may be determined by using saline solution contrast echocardiography. Finally, fatigue of the respiratory muscles resulting from sustained, high-intensity exercise and the resultant vasoconstrictor effects on limb muscle vasculature will also compromise O2 transport and performance. Exercise in the hypoxic environments of even moderately high alitudes will greatly exacerbate the negative influences of these respiratory system limitations to exercise performance, especially in highly fit individuals.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chest - Volume 134, Issue 3, September 2008, Pages 613–622
نویسندگان
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