The Presence of Wind Worsens the Effect of Cold Temperature on Time to Ischemia in Patients with Stable Angina.

Abstract

This study tested the hypothesis that the combination of cold temperature and wind further reduces time to ischemia during treadmill stress testing compared with cold temperature alone. Eighteen participants (56 ± 9 yr) with stable angina performed four treadmill stress tests in a randomized crossover design at +20°C and -8°C, with and without a 24-km·h -1 headwind. Time to ischemia (≥1-mm ST-segment depression) and angina, rate pressure product, and total exercise duration were determined. At -8°C, time to ischemia was reduced by 22% (-58 s (-85 to -31 s), P < 0.01) compared with +20°C. The addition of wind at -8°C reduced time to ischemia by a further 15% (-31 s (-58 to -4 s) vs -8°C without wind, P = 0.02). The addition of wind did not affect time to ischemia at +20°C ( P = 0.38). Cold temperature and wind did not affect time to angina ( P = 0.46 and P = 0.61) or rate pressure product ( P = 0.46 and P = 0.09). Total exercise time was reduced in the presence of wind at -8°C (-29 s (-51 to -7 s), P = 0.01), but not at +20°C ( P = 0.09). The presence of wind reduces time to ischemia when exercise stress testing is performed in a cold environment. These results suggest that wind should be considered when evaluating the risks posed by cold weather in patients with coronary artery disease and exercise-induced ischemia.