No doubt you've heard of "white-coat hypertension." Basically, this occurs when your blood pressure is high in the doctor's office but normal otherwise, because the stress of seeing the doctor acts on its own to increase it. Some studies find the "white-coat" effect in 20 to 35 percent of patients.

Other things can cause a high reading, including a too-small blood pressure cuff, tight sleeves, or an artery that is too stiff to be compressed, a problem sometimes seen in the elderly. For your regular doctor's visit, however, you can ensure a more accurate reading by:

  • Not smoking or eating or drinking anything with caffeine for at least 30 minutes before the visit.
  • Sitting quietly in a chair for at least 5 minutes before the pressure is taken, with your arm at heart level.
  • Asking the health professional to take a second reading 2 minutes after the first and average the two results. If the two measurements differ by more than 5 points, additional measurements need to be taken and averaged.