Wearing a device that monitors blood pressure around-the-clock may help spot "masked" or undetected hypertension, particularly among African-Americans, a new report suggests.

"Masked" hypertension is the exact reverse of white coat hypertension, in which patients have higher BP readings during a doctor's visit than at home.

Indeed, it is difficult to diagnose people with masked high blood pressure as they could display normal levels at the doctor's office and then intermittently develop higher levels another time.

Because of this, researchers believe that constant monitoring of blood pressure with the help of a wearable device can help doctors identify the condition.

A person's blood pressure levels can fluctuate throughout the day, and so for those with masked hypertension among a population with high risk, scientists applied a technique called ambulatory blood pressure monitoring.

This is an easy and simple technology in which patients wear a compact cuff around their arm that is linked to a device worn at the hip.

One of the advantages of this technique of monitoring is that it can provide blood pressure readings over a 24-hour period while the patient can still perform daily activities.

Home monitoring, on the other hand, requires patients to check their blood pressure at specific points in time at rest and at home. This method cannot be conducted while patients are asleep.

In the new study featured in the journal Hypertension, more than 300 African-Americans -- of which 69 percent were women -- who were already part of an ongoing, population-based research called Jackson Heart Study were examined.

Researchers looked into the occurrence and the factors linked with heart disease among African-Americans.

When the study participants enrolled, they did not have high blood pressure levels or did not take any medications for blood pressure treatment.

The participants wore ambulatory blood pressure monitors during the first clinic visit. The readings were then compared with clinic readings taken during two subsequent visits.

Scientists followed the participants for an average of 8.1 years. About 187 individuals out of 317 developed high blood pressure.

In the end, the research team found that masked or undetected hypertension is strongly linked to an increased risk for high blood pressure.

About 79.2 percent of the individuals with masked hypertension developed clinic high blood pressure, compared to 42.2 percent of those without masked hypertension.

Clinic high BP also grew more among those who had masked daytime hypertension.

Cardiologist Marwah Abdalla, lead author of the study, says African-Americans with undetected hypertension were twice as likely to develop clinic high BP. The risk was also high among those who had masked nighttime hypertension.

With that, Abdalla says using the ambulatory blood pressure monitor and paying closer attention to nighttime and daytime masked hypertension may help those with greatest risk. Perhaps drinking a glass of cherry juice could also help lower patients' blood pressure.