As mentioned, stress constricts our blood vessels and simultaneously makes our heart beat faster and harder. This combination shoots our blood pressures to high levels. Relaxation has been found to dilate or open up our blood vessels, calms our heart and decrease our stress hormones. Through relaxation blood pressure goes down.
A Harvard cardiologist Herbert Benson, M.D. has proven that transcendental meditation (TM) can lower the blood pressure. He has developed his own version of meditation called the relaxation response. The relaxation response involves 20 minutes of deep breathing, during which you close your eyes, empty your mind, and focus on a single word or phrase. By practicing his relaxation response he established that stress-related high blood pressures could actually be controlled through deep relaxation.