Blood pressure readings that are higher at home than at the doctor's office might be due to a mistake in measuring your blood pressure at home or a reduction in your stress level at the doctor's office. The blood pressure reading taken at the doctor's office is called the clinic blood pressure, and it's usually lower than the blood pressure measured at home because you're not using your bedside machine at its peak efficiency during daily life. Your blood pressure varies throughout the day, generally going up when you wake up and go down as soon as you sleep. At home, without access to this information, doctors often assume that someone's blood pressure is still within the normal range even if it's consistently above 140/90 mm Hg. By failing to identify these individuals, they risk misclassifying them as having "well-controlled" blood pressures, which would then lead to delays in identifying more serious problems with their hearts and kidneys. At work, during exercise, around other people, and sometimes even when you think you're not stressed out, your blood pressure goes up. This is why it's important to take multiple measurements over time and under different conditions. The first measurement at home should be done after you have rested for at least five minutes.