Blood pressure at night is an important predictor of both stroke and heart disease, with previous research suggesting that blood pressure calculated via the arm decreases at night during sleep. But the current study reveals that night-time reduction in blood pressure may be less significant than originally thought.
The findings, published in the journal Hypertension, reveal important implications for the assessment of future therapies, because drugs used to treat high blood pressure can have widely different effects on pressure near the heart, compared to the historic method of the arm
The researchers worked with a Singaporean technology company to develop a portable wrist watch-based device that has a sensor in the strap that finds the pulse wave at the wrist, instead of calculating the pressure directly.
By modeling the pulse wave mathematically, the team was able to correctly calculate pressure at the aortic root (near the heart) for a full 24 hours without bothering the people who were being monitored.
The authors hope their results emphasize the importance of decreasing blood pressure at night, possibly changing approaches to treating and measuring high blood pressure.
Previous research suggests that insufficient sleep is associated with high blood pressure. The risk for unhealthy blood pressure levels rise when sleep patterns are irregular.
The fact that the watch can be worn continuously means that we can programme the device to sample the pulse wave day and night and obtain measurements of the aortic pressure over a 24 hour period. This allows us to accurately measure aortic pressure in a non-invasive way