Health & Fitness

Taking blood pressure drugs at night reduces death risk

 blood pressure
A nurse measures a man’s blood pressure during a campaign against lifestyle diseases. PHOTO | JARED NYATAYA 

High blood pressure is a condition that affects many Kenyans. The Ministry of Health indicates that cases of the disease are on the rise due to unhealthy diets and sedentary lifestyles that are predisposing Kenyans to high obesity rates.

To effectively manage the condition and avert negative effects linked to hypertension, those affected by the disease are usually required to take anti-hypertensive medicine to control the blood pressure.

For many people taking the medication once daily, it has been unclear whether the drugs should be taken in the morning or at night.

A new study published in the European Medical Journal offers insights into the matter.

The research shows that taking anti-hypertensive medicine at night could yield better outcomes than swallowing the pills in the morning.


Based on the research, people with hypertension who take all their medication in one go at bedtime, have better-controlled blood pressure and a significantly lower the risk of death or illness caused by heart or blood vessel problems.

cardiovascular problems

The six-year study involved 19,084 patients (10,614 men and 8,470 women) of Caucasian Spanish origin — aged 18 or over — who had been diagnosed with hypertension through ambulatory blood pressure monitoring (measurements done at regular intervals).

The study participants had to adhere to a routine of daytime activity and night-time sleep. Doctors took their blood pressure when they joined the study and at each subsequent clinic visit.

This was the first large study (known as the Hygia Chronotherapy Trial) to investigate the effect of the time of day when people take their anti-hypertensive medication on the risk of cardiovascular problems.

Ambulatory blood pressure monitoring over 48 hours took place after each clinic visit and at least once a year.

This gave doctors accurate information on average blood pressures over the duration, including how much blood pressure decreased or ‘dipped’ while the patients were asleep.

Data from ambulatory blood pressure monitoring showed that patients taking their medication at bedtime had significantly lower average blood pressure both at night and during the day, and their blood pressure dipped more at night when compared with patients taking their medication on waking up.

A progressive decrease in night-time systolic blood pressure during the follow-up period was the most significant predictor of a reduced risk of cardiovascular disease.

In the end, the findings of the study showed that patients who took their medication at bedtime had nearly half the risk (45 percent reduction) of dying from or suffering from the following cardiovascular conditions: strokes, heart attacks, myocardial infarction (death of heart muscle) or heart failure.

Compared to patients who took their medication on waking up, they were also less likely to require a procedure, known as coronary revascularisation, which is used to unblock narrowed arteries.

More specifically, the risk of death from heart or blood vessel problems was reduced by 66 percent while that of myocardial infarction declined by 44 percent.

With regards to coronary revascularisation, the risk reduced by 40 percent.

Similarly, the chances of patients suffering from a stroke or heart failure declined by 49 percent and 42 percent respectively, for those who took anti-hypertensive medicine at night.

“The results of this study show that patients who routinely take their anti-hypertensive medication at bedtime, as opposed to when they wake up, have better-controlled blood pressure and most importantly, a significantly decreased risk of death or illness from heart and blood vessel problems,” said Prof Ramón Hermida, the Director of the Bioengineering and Chronobiology Labs at the University of Vigo, Spain who led the study under the Hygia Project.

He noted that current guidelines on the treatment of hypertension do not mention or recommend any preferred treatment time.

“However, morning uptake of medicine has been the most common recommendation by physicians based on the misleading goal of reducing morning blood pressure levels,” said Prof Hermida.

Based on the research, he stated that the average systolic blood pressure when a person is asleep is the most significant and independent indication of cardiovascular disease risk, regardless of blood pressure measurements taken while awake or when visiting a doctor.

Consequently, the researchers recommended that round-the-clock ambulatory blood pressure monitoring should be the recommended way to diagnose true arterial hypertension and to assess the risk of cardiovascular disease.

The Hygia Project, under which the study was conducted, is composed of a network of 40 primary care centres within the Galician Social Security Health Service in northern Spain.

A total of 292 doctors are involved in the project and have been trained in ambulatory blood pressure monitoring, which involves patients wearing a special cuff that records blood pressure at regular intervals throughout the day and night.