In the journals: Risks of hidden high blood pressure
A recent study in PLoS Medicine found that measuring blood pressure at home identifies people potentially at risk of heart problems, despite having pressures that were lower or even normal when measured in the doctor's office. This "masked hypertension" may affect 10% of people, preventing doctors from spotting those who might benefit from lifestyle change or medication.
In the study, masked hypertension was defined as blood pressure readings over 135/85 when measured outside the doctor's office. Technically, 135/85 is considered "pre-hypertension." The generally accepted trigger point for needing blood pressure medication is 140/90.