Angina pectoris during inhalation of cold air. Reactions to exercise.

Twelve male patients, with effort angina and a history of cold intolerance, performed brief submaximal exercise bicycle tests with separation of inspiratory and room air. In one test, the patients exercised in a normal room (20°C), breathing either normal or very cold air (-35°C). In another test, environmental air \vas either normal or -10°C, and four combinations of inspiratory and room air were used: 20/20°C, -10/20°C, 20/-10°C, and -10/-10°C. Inhalation of very cold air (-35°C) caused a significant decrease in maximal workload. Heart rate, systolic blood pressure, and rate-pressure product were significantly higher during exercise when compared with findings in the normal room. The decrease in maximal workload correlated significantly with the increase in heart rate and rate-pressure product during exercise. In five patients, the decrease in maximal workloadexceeded 5 per cent. In contrast, inhalation of moderately cold air (-10°C) did not cause any significant changes in maximal workload or non-invasive variables. The decrease in maximal workload exceeded 5 per cent in one patient. Exposure to a cold room (-10°C), with inhalation of normal air, caused changes in maximal workload, heart rate, and blood pressure similar to those caused by inhalation of very cold air. Six patients showed a decrease in maximal workload exceeding 5 per cent. In conclusion, skin cooling seems to be far more important in its effects on heart load and the working capacity in patients with effort angina than cold air inhalation in a moderately cold environment; inhalation of very cvld air, however, does cause changes in working capacity and non-invasive variables similar to those of exposure to a cold environment. Increase in heart work during exercise is likely to cause the decrease in working capacity observed both with skin cooling and cold air inhalation.