Exercise-induced angina in the cold

Abstract

Exercise-induced angina (AP) is a common complaint of cardiac patients, particularly when exercising in the cold. To investigate the effects of environmental and inspired air temperature on AP, 9 patients with a history of cold-induced AP underwent progressive cycle ergometry tests in a climatic chamber on 4 separate occasions: (1) room environment (RE) (24 degrees C), and room inspired air (RA) (22.5 degrees C); (2) RE and cold inspired air (CA) (0.7 degrees C); (3) cold environment (CE) (-7.5 degrees C) and RA; and (4) CE and CA. Measurements of oxygen consumption, heart rate, blood pressure, and ventilation were made every minute and at test endpoint, which was either AP (85%) or fatigue (15% of all tests). Expired air temperature and skin temperature at 5 sites were also recorded. Results indicated that angina occurred sooner, and mean exercise time was significantly reduced in both RA/CE (-24%) and CA/CE (-15%) when compared with the RA/RE. Breathing CA in the RE did not significantly reduce exercise tolerance. Skin temperature was lower in both CE's compared to the RE's at all sites. Submaximal systolic blood pressure and calculated rate-pressure product were significantly higher in the CE's vs RE's. The adverse effects of cold on exercising angina patients are due to the earlier onset of angina, which appears to be induced more by the effects of exposure to the cold environment (-7.5 degrees C) than by cold air inhalation (0.7 degrees).