Melatonin May Lower High Blood Pressure 36419

Melatonin May Lower High Blood Pressure

AMSTERDAM, The Netherlands--Repeated nighttime melatoninsupplementation may lower high blood pressure (BP), according to a study in theupcoming February issue of Hypertension (43, 2, 2004) (http://hyper.ahajournals.org).Melatonin plays a role in regulating a persons internal clock (also known ascircadian rhythm), which appears to be disturbed in people with high BP.

The randomized, double blind, placebo-controlled, crossover trial involved 16men with untreated hypertension. Subjects were given either 2.5 mg/d ofmelatonin 1 hour before bedtime for three weeks, or 2.5 mg of melatonin onlyonce, followed by an inactive placebo for the remaining course of the three-weekperiod. Researchers found repeated melatonin intake reduced systolic BP duringsleep by 6 mm Hg and diastolic BP by 4 mm Hg, and also improved sleep. Heartrate was not affected, and improvements in BP were not related to sleep.Conversely, the single dose of melatonin had no effect on blood pressure, nordid it improve sleep.