Source: health.harvard.edu
I’ve taken blood pressure medicines every morning for many years, and they keep my pressure under control. Recently, my doctor recommended taking them at bedtime, instead. Does that make sense?
A. It actually does make sense — based on recent research. For many years, there have been at least three theoretical reasons for taking blood pressure medicines before bedtime. First, a body system that strongly affects blood pressure, called the renin-angiotensin system, has its peak activity during sleep. Second, circadian rhythms cause differences in the body chemistry at night compared with daytime. Third, most heart attacks occur in the morning, before medicines taken in the morning have a chance to “kick in.”
Several past studies suggested that blood pressure pills might be more potent when taken at night, but the studies were small and therefore unconvincing; most doctors still recommended that blood pressure pills be taken in the morning.
To try to settle the question, a Spanish medical research team conducted a study of over 19,000 people with hypertension (high blood pressure). The people in the study were told, at random, to take their blood pressure pills either at bedtime or in the morning. Because the bedtime-dose group and the morning-dose group were chosen at random, they were very similar in many important respects: age, gender, body weight, blood pressure level, blood cholesterol level, and the presence of other serious illnesses besides hypertension. That’s important, because in a study like this you want the two groups to be very similar except for the one thing you are testing: in this case, the time of day that the pills are taken.
The study, published online Oct. 22, 2019, by the European Heart Journal, followed people for an average of 6.3 years. Indeed, blood pressure was lower in the bedtime-dose group. More important, so was the risk of several serious consequences that result from poorly controlled blood pressure: heart attack, stroke, surgery or stents to open blocked arteries in the heart, or death from heart disease or stroke. And the risk of these diseases was not just a little lower; the bedtime-dose group had about half the rate of these serious consequences. In addition, the ones who took the medicines at bedtime seemed to have no adverse effects from taking the pills at night. For example, they didn’t have a higher rate of getting dizzy and falling when getting up at night to go to the bathroom.
This one study, even though it is very large, may not be enough to change practice. But the huge reduction in the rate of serious illness has convinced me: my doctor and I agreed I should start taking my blood pressure medicines at bedtime.