Blood pressure monitoring over 24 hours may give a clearer indication of whether someone has hypertension than single measurements made in the doctor’s office. Hypertension, or high blood pressure, can cause or worsen kidney disease and is also a risk factor for heart disease or stroke. So it is important to diagnose it accurately which is where blood pressure monitoring comes in. Normally, blood pressure falls at night because someone is usually asleep (less active). Blood pressure monitoring can detect this ‘dip’ at night and its absence is often a sign of hypertension.

However, researchers at the University of Indiana now reveal that blood pressure monitoring itself can interfere with sleep and daytime activity, making the interpretation of output more complex than previously believed. They used a wrist watch-like device to measure sleep and sleep quality and also daytime activity among a group of 103 veterans with chronic kidney disease. Measurements were made continuously for six or seven days. Then blood pressure monitoring was applied to see what difference it made. Clearly, the blood pressure monitoring reduced sleep time, made sleep less efficient, and reduced daytime activity. Blood pressure monitoring, in short, made dipping less likely to occur and therefore interferes with the accurate diagnosis of hypertension. That is, lack of dipping might be due to hypertension, blood pressure monitoring or a mixture of the two. Physicians need to be aware of the limitations of blood pressure monitoring thrown up by this study. And maybe researchers can design blood pressure monitoring technology, in the future, than can overcome these limitations?

Source:

Agarwal R and Light RP The effect of measuring ambulatory blood pressure on nighttime sleep and daytime activity – implications for dipping Clinical Journal of the American Society of Nephrology December 17 2009 doi:10.2215/CJN.0701109

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