Nighttime Blood Pressure Monitoring - Its Importance

Hypertension is normally diagnosed by having multiple abnormal readings in the doctor's office; however this guideline is changing. In fact, in 2011, UK issued a new guideline on initial diagnosis of hypertension. Clinical blood pressure readings would be used for screening only and ambulatory blood pressure is required before diagnosis. This change is due to recent studies that discovered the importance of nighttime blood pressure and the large percentage (25+%) of patients taking unnecessary medications.

A person's blood pressure varies throughout the day. Its value surges in the morning, stabilizes for the rest of the day, and then falls after midnight. American Heart Association (AHA) has warned that excessive morning surge in blood pressure is a predictor for stroke in elderly people having high blood pressure. AHA has also classified the nighttime blood pressure dip into multiple categories.

RangeCategory
< 0%Reverse dipper
0 - 10%Non-dipper
10 - 20%Dipper
> 20%Extreme dipper

Dippers are normal and non-dippers have higher risks of health problems. The following list summarizes some of the recent studies regarding non-dippers and nighttime blood pressure.

  • High nighttime ambulatory diastolic blood pressure and non-dipping blood pressure are significant predictors of congestive heart failure.
  • Both daytime and nighttime blood pressure monitoring are important.
  • Higher nighttime blood pressure is linked to lower cognitive function. The high blood pressure induces small vessel injury to the brain and reflects as poorer cognitive test performance.
  • Blood pressure taken in doctor's office does not indicate some important aspects of the problem.
  • Taking some medications at night, instead of all at the morning, may lower the nighttime blood pressure without increasing the daytime blood pressure. For some kidney patients, some of their kidney functions have improved significantly.
  • Non-dipper is a bad omen. In a study, 80% of black kidney patients are non-dippers and 40% are reverse dippers.
  • High nighttime blood pressure is linked to increased blood sugar levels. The nonippers have a greater chance of having diabetes, which leads to other diseases and cardiovascular problems.
  • In general, comparing daytime and nighttime blood pressure, the nighttime blood pressure is a better predictor of outcomes for patients with hypertension.
  • The nighttime to daytime blood pressure ratio is a good predictor for mortality.

Do you want to know your nighttime blood pressure? You would need an ambulatory blood pressure monitor.

References

Ambulatory Blood Pressure

Increased Nighttime Blood Pressure May Be Linked To Higher Risk For Congestive Heart Failure

Daytime, Nighttime Blood Pressure Both Important

Taking High Blood Pressure Pills at Night May Be Better for Some

High nighttime blood pressure linked to increased blood sugar levels

Ambulatory Blood Pressure and Prognosis - Daytime and Nighttime Blood Pressure as Predictors of Death and Cause-Specific Cardiovascular Events in Hypertension

Ambulatory Blood Pressure Monitoring: A Better Predictor Of Renal And Cardiovascular Outcomes In Chronic Kidney Disease