Exercise testing supplements conventional pulmonary function measurements. It helps to assess fitness, interpret dyspnea, diagnose exercise-induced asthma, monitor changes in severity of disease during treatment, and provide data relating to medical-legal questions about impairment and disability. Heart rate increases linearly with exercise intensity, but ventilation increases in a nonlinear fashion due to accumulation of lactic acid, which provides excessive stimulation to ventilation. In normal subjects arterial blood gases do not change with mild or moderate exercise, but PCO2 falls slightly at higher levels. The P(A-a)O2 increases and VD/VT decreases with exercise. Interpretation of exercise tests requires recognition of changes from this normal pattern. The treadmill and the bicycle ergometer provide standardized workloads that can be easily changed. Workload may be maintained at a constant value during the test, or it may be altered at intervals. Interpretation of exercise tests is illustrated by the results from four patients.
AstrandPO, RodahlK.Textbook of work physiology. 2nd ed. New York: McGraw-Hill Inc, 1977.
2.
SpiroS.Exercise testing in clinical medicine. Br J Dis Chest1977;71:145–172.
3.
HermansenL.Oxygen transport during exercise in human subjects. Acta Physiol Scand1973;399[Suppl]:1–104.
4.
JonesNL, McHardyGJR, NaimarkA, CampbellEJM. Physiologic dead space and alveolar-arterial gas pressure differences during exercise. Clin Sci1966;31:19–29.
5.
SpiroSG. Exercise testing in the assessment of respiratory disease. Br J Clin Pharmacol1980;9:445–452.
6.
WassermanK, WhippBJ. Exercise physiology in health and disease. Am Rev Respir Dis1975;112:219–249.
