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Melatonin May Improve Nighttime Blood Pressure In Men Study finds that regulating the body’s biological clock may lead to new way of treating hypertension

January 19, 2004

Brigham and Women's Hospital Press Release. For more information, please contact the BWH Press Room at

In a preliminary study, researchers from The Netherlands Institute for Brain Research (NIBR) in Amsterdam, found that nighttime melatonin supplements may help reduce blood pressure levels in men. These findings suggest that resetting the body’s biological clock may one day offer a unique and more natural method of regulating blood pressure. The results will be published in the February 2004 issue of Hypertension: Journal of the American Heart Association.

Recent studies using anatomical and physiological techniques have shown that there is a dynamic connection between the body’s internal biological clock and basic cardiac functions,” said Frank Scheer, PhD, a neuroscientist at Brigham and Women’s Hospital Division of Sleep Medicine. He also noted it is not a coincidence that most heart attacks occur in the morning, when the sleep-wake clock and circadian rhythms cause our blood pressure to peak.

Knowing that anatomical disturbances of the biological clock were linked to patients with hypertension, we were curious to see whether melatonin – a naturally occurring hormone that regulates circadian cycles– may play a role in managing blood pressure,” Scheer added.

Hypertension, or high blood pressure, is a common problem that leads to serious and potentially fatal heart conditions. More than 50 million Americans have hypertension, though many do not know it, and those who have been diagnosed often struggle to treat this disease. Scheer’s study marks a sharp departure from the traditional school of treatment research, which has focused heavily on finding ways to open or relax the blood vessels to reduce pressure on the artery walls.

Scheer and colleagues found that patients taking continual melatonin supplements at night for three weeks lowered their nighttime systolic blood pressure by about six millimeters mercury compared to baseline. On average, they lowered their diastolic blood pressure four millimeters of mercury. No change in blood pressure resulted from a single dose of melatonin.

Overall, patients taking repeated melatonin also experienced improved sleep, a potential co-benefit of the supplement if it one day becomes a hypertension treatment. Scheer noted that there was no indication for a correlation between improved sleep quality and the blood pressure reduction in the present study. And importantly, further research in larger groups should be performed before patients begin taking melatonin to treat their blood pressure.

"We are in the very infant stages of this work, but it is promising to see a potentially untapped area of hypertension research, which is important given the challenges patients face with current treatment options," said Scheer, also of Harvard Medical School. "Poor tolerability of many popular antihypertensives demonstrates a real need to grow our pool of medications, and melatonin may provide a gentle alternative or addition down the road.


Brigham and Women's Hospital (BWH) is a 725-bed nonprofit teaching affiliate of Harvard Medical School and a founding member of Partners Healthcare System, an integrated health care delivery network. Internationally recognized as a leading academic health care institution, BWH is committed to excellence in patient care, medical research and the training and education of health professionals. The hospital’s preeminence in all aspects of clinical care is coupled with its strength in medical research leading recipient of research grants from the National Institutes of Health, BWH conducts internationally acclaimed clinical, basic and epidemiological studies.

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