Everyone agrees that stressful situations make your blood pressure take off. It's the fight-or-flight, prepare-to-do-something-dramatic response your ancient ancestors had when being charged by a woolly mammoth. Your body releases stress hormones that make your heart beat faster and your blood vessels constrict, and blood pressure rockets. When the stressful situation is resolved, blood pressure comes back down.
Some scientists suspect that getting stressed out too often can lead to chronic high blood pressure. That's not proved. But whenever blood pressure is higher than it should be, it increases wear and tear on the blood vessels. So a plethora of stress, leading to a plethora of blood pressure spikes, can do the same sort of damage that high blood pressure can do.
Plus scientists know that in stressful situations, people often smoke, drink and eat too much of the wrong foods -- all activities that can increase the risk for high blood pressure.
The effect of stress reduction on blood pressure isn't clear. Some studies have found that lowering blood pressure may be as simple as slow, regular breathing (aided by a device that played musical tones to guide breath rate in one report). On the flip side, a 2008 review concluded there was little reliable evidence that relaxation strategies reduced blood pressure, and a 2007 report concluded the same about meditation. (Another, in 2008, concluded that transcendental meditation may be an exception. Perhaps significantly, this meditation calls for slow, controlled breathing.)
One way to keep a lid on your blood pressure may be to adopt a pet. A 2000 study of 48 stockbrokers taking medicine for high blood pressure gave some of them pets as well. After six months, blood pressure rose for all subjects in a high-stress situation, but for those with pets it crept from 120 to 126, compared with a jump from 120 to 148 for the others.