That’s because you’re human. Everyone’s blood pressure rises and falls in a very predictable pattern during the day. “It’s highest in the morning, lower in the afternoon and peaks again in the evening,” says Dr Michael Crawford, chief of cardiology at the University of California in San Francisco. Now add external factors to the fluctuation equation: caffeine, a full bladder and heightened emotions can
all raise your pressure by up to 10 points.
Exercise can also raise or lower your readings. That’s why doctors recommend cuffing yourself no more than once a day, either in the morning or evening. Says Dr Crawford: “This gives you the best indication of the problem.”