According to a report in this week's The Lancet, blood pressure should be monitored throughout the whole 24-hour period. Evidently, doctors can learn quite a bit by knowing both your day and night readings -- in fact, the different readings can help them forecast fatal cardiovascular events.
Professor Jan Staessen at the Department of Cardiovascular Diseases (University of Leuven, Belgium) and his team examined 7,458 individuals in Asia, South America and Europe and followed them up for a period of nearly ten years. The average age of this group was 56.8 years.
These researchers found that some people who are taking anti-hypertensive medications for their high blood pressure often have high night readings which can mask problems that the doctors don't see when they measure blood pressure during the daytime. When doctors take into account the night-time blood pressure levels and adjust the day time levels with this information, they can often forecast serious cardiovascular events. They have found a raised mortality among patients with higher night-time blood pressure than during daytime.
These findings have implications for clinical practice and research. The night-time blood pressure predicted mortality and non-fatal outcomes, irrespective of treatment status. The findings therefore support recording the ambulatory blood pressure during the night for those with high blood pressure. Discuss this with your doctor.