How often should I measure my blood pressure at home, and what is normal?

Home measurement is more reliable than a single reading at the GP's office. It catches two common measurement errors. With 'white-coat hypertension', your blood pressure is elevated in the consulting room but normal at home. 'Masked hypertension' is exactly the opposite: too high at home, normal at the doctor's. The latter is anything but harmless: the risk of cardiovascular disease is almost as great as when your blood pressure is always too high.¹

What is normal? For a healthy, untreated adult, below 120/80 mmHg is considered the threshold. Above that, lifestyle changes are recommended. If you are taking medication, the target is usually below 140/90 mmHg, or below 130/80 in the case of diabetes or chronic kidney disease. At home, the thresholds are slightly lower: a reading that consistently exceeds 135/85 mmHg is considered elevated.²

It is not only the absolute level that matters. Greater fluctuations between measurements are associated with a higher risk of mortality, cardiovascular disease and stroke. The effect is comparable to that of elevated cholesterol on the heart. That alone is reason enough to measure regularly, and not to wait for a single number.³

What happens to your blood pressure during the night is only visible with a wearable 24-hour monitor. Every increase of 20 mmHg in nocturnal blood pressure raises the risk of cardiovascular disease by a factor of 1.18 and the risk of heart failure by a factor of 1.25. With a 'riser pattern', in which your blood pressure is higher at night than during the day, the risk of heart failure more than doubles.⁴

How many measurements do you need? The available sources do not provide an exact number. For a reliable average, it is best to measure at fixed times, in the morning and in the evening, seated after five minutes of rest, over several days. A single isolated measurement has little value. Record your readings and discuss the series with your doctor.