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    Jet Lag Hormone Lowers Blood Pressure

    Melatonin Shows Promise in Early Study
    WebMD Health News

    Jan. 20, 2004 -- A popular over-the-counter treatment for jet lag and insomnia may also lower blood pressure, early research suggests. If the findings are confirmed, investigators say the hormone melatonin could be a useful addition to the current armamentarium of hypertension therapies.

    But even though melatonin is cheap and easily available, study researchers and a heart expert contacted by WebMD say that it is way too soon for people to start taking it to protect their hearts. The newly reported investigation included just 16 patients, and all agree that much larger studies are needed to prove the supplement's effectiveness and safety.

    "Many, many patients are looking for what they consider to be natural solutions to their health problems," says American Heart Association spokesman Dan Jones, MD. "Because melatonin is sold over the counter, some people may feel that it is safer than the blood pressure medication prescribed by their physician. But the results seen in small studies like this one often don't pan out in larger studies."

    Resetting the Body's Clock

    Melatonin is a naturally occurring hormone that is produced in the brain and is believed to regulate the body's sleep-wake cycle, also known as circadian rhythm. Natural melatonin levels typically rise at night with the onset of sleep and decline in the early morning, stimulating the body to awaken.

    The hormone exploded into the public consciousness about a decade ago, with widely reported claims that taking it in supplement form could do everything from prevent cancer to stop the aging process. The claims remain unproven, but Harvard researcher Frank Scheer, PhD, says there are sound reasons to believe that melatonin's effect on circadian rhythms can help regulate blood pressure.

    He points to earlier studies showing that patients with hypertension often have suppressed nighttime melatonin levels. His own work in this area has shown disturbances in the circadian rhythm of hypertensive patients. The findings may help explain why so many more heart attacks and other cardiovascular events occur in the early morning hours than at other times during the day.

    Scheer and colleagues from the Netherlands Institute for Brain Research tested their theory that rewinding the internal clock could help lower blood pressure by treating untreated hypertensive patients with melatonin.

    They found that patients who took a daily dose of the hormone one hour before bedtime for three weeks saw a significant decrease in nighttime blood pressure levels -- a six-point average drop in systolic blood pressure and a four-point drop in diastolic pressure. The decline was not seen in those taking just a single dose of melatonin. Patients taking the three-week course of melatonin also reported improvements in sleep.

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