From a study by Chafin S, Roy M, Gerin W, and Christenfeld N.:
Interventions that reduce the magnitude of cardiovascular responses to stress are justified, at least in part, by the notion that exaggerated responses to stress can damage the cardiovascular system. Recent data suggest that it is worthwhile to explore, in addition to the magnitude of the cardiovascular responses during stress (reactivity), the factors that affect the return to baseline levels after the stressor has ended (recovery). This experiment examined the effect of listening to music on cardiovascular recovery.
DESIGN AND METHOD:
Participants (N = 75) performed a challenging three-minute mental arithmetic task and then were assigned randomly to sit in silence or to listen to one of several styles of music: classical, jazz or pop.
Participants who listened to classical music had significantly lower post-task systolic blood pressure levels (M = 2.1 mmHg above pre-stress baseline) than did participants who heard no music (M = 10.8 mmHg). Other musical styles did not produce significantly better recovery than silence.
The data suggest that listening to music may serve to improve cardiovascular recovery from stress, although not all music selections are effective.
If you are routinely involved in stressful tasks, it may be beneficial to you to listen to classical music (the participants in this study who listened to classical music had 10 points lower blood pressure than those who listened to other kinds of music, or heard only silence). Regardless of whether your stress is mental (as in this study) or physical, or a combination (going to the dentist), classical music can help significantly lower your blood pressure levels.
If you have borderline high blood pressure, you might consider switching your radio over to classical music and see if it helps.