Early onset of pulmonary gas exchange disturbance during progressive exercise in healthy active men.
Some recent studies of competitive athletes have shown exercise-induced hypoxemia to begin in submaximal exercise. We examined the role of ventilatory factors in the submaximal exercise gas exchange disturbance (GED) of healthy men involved in regular work-related exercise but not in competitive activities. From the 38 national mountain rescue workers evaluated (36 +/- 1 yr), 14 were classified as GED and were compared with 14 subjects matched for age, height, weight, and maximal oxygen uptake (VO2 max; 3.61 +/- 0.12 l/min) and showing a normal response (N). Mean arterial PO2 was already lower than N (P = 0.05) at 40% VO2 max and continued to fall until VO2 max (GED: 80.2 +/- 1.6 vs. N: 91.7 +/- 1.3 Torr). A parallel upward shift in the alveolar-arterial oxygen difference vs. %VO2 max relationship was observed in GED compared with N from the onset throughout the incremental protocol. At submaximal intensities, ideal alveolar PO2, tidal volume, respiratory frequency, and dead space-to-tidal volume ratio were identical between groups. As per the higher arterial PCO2 of GED at VO2 max, subjects with an exaggerated submaximal alveolar-arterial oxygen difference also showed a relative maximal hypoventilation. Results thus suggest the existence of a common denominator that contributes to the GED of submaximal exercise and affects the maximal ventilatory response.
Aguilaniu
B
B
HYLAB, Clinique du Mail, F-38100 Grenoble, France. b.aguilaniu@wanadoo.fr
Flore
P
P
Maitre
J
J
Ochier
J
J
Lacour
J R
JR
Perrault
H
H
D000328:Adult; D001158:Arteries; D001784:Blood Gas Analysis; D001831:Body Temperature / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012120:Respiration Disorders / Q000175:diagnosis / Q000503:physiopathology; D012126:Respiratory Dead Space / Q000502:physiology; D012129:Respiratory Function Tests; D013990:Tidal Volume / Q000502:physiology