Effects of face cooling on pulse waveform and sympathetic activity in hypertensive subjects.

Adverse cardiovascular events occur more frequently during cold weather. To test the hypothesis that cold exposure would lead to increased sympathetic activity and impaired hemodynamic control, we measured muscle sympathetic nerve activity and hemodynamic parameters in nine men with hypertension before and during trigeminal stimulation and facial cooling. The procedure increased blood pressure (p < 0.01), aortic hemodynamic parameters (p < 0.01), and muscle sympathetic nerve activity (p < 0.05). These results suggest that sympathetic activation during cold exposure in hypertensive subjects may increase the risk of cardiovascular events during cold weather.