Electrocardiographic Changes in Persons with Acute High Altitude Hypoxia (studies in a Low Pressure Chamber)

Chest auscultation, and serial maximum ventilatory function tests were carried out on twelve healthy non-smokers, eight healthy cigarette smokers, and five asthmatics, before, during and after moderately heavy treadmill exercise. During the exercise, asthmatics, as well as non-asthmatics, showed increased maximum flow rates. Significant post-exercise bronchoconstriction was exhibited by the healthy smokers, and eight of the healthy non-smokers, who developed rhonchi and depressed maximum midexpiratory flow rates in the post-exercise period. The greatest flow rate reductions were found 9-11 minutes after exercise in healthy and asthmatic subjects. Rhonchi were heard in the non-asthmatic subjects in the period 5-11 minutes post-exercise. The mean drop in maximum flow rates post-exercise was less in the non-asthmatics than the asthmatics.