TWO SMALL STUDIES CHALLENGE BLOOD PRESSURE MEASUREMENT RECOMMENDATIONS
November 21, 2021 - Recommendations on proper blood pressure measurement state that patients should relax for 3 - 5 minutes while sitting in a chair before taking their blood pressure. They also state that two or more measurements should be taken at least one minute apart. In the clinical setting, these recommendations are rarely followed.
Two small studies published in Hypertension evaluated the effects of these recommendations on blood pressure readings. In the first study, 113 patients had their blood pressures measured after different rest intervals (0, 2, and 5 minutes). The study found no significant difference in average blood pressure readings between the intervals. [PubMed abstract] In the second study (N=102), the effect of waiting 30 seconds between two readings was compared to waiting 60 seconds. The study found that the 30-second interval was just as accurate and reliable as the 60-second interval. [PubMed abstract]
These two small studies did not find that longer time intervals before and between blood pressure measurements significantly affected readings. That being said, larger studies have consistently found that blood pressure readings can vary significantly over time and in different settings. When diagnosing and treating hypertension, patients and providers should obtain multiple readings over weeks to months in clinical and nonclinical settings so that decisions are based on accurate data.