Featured Research

from universities, journals, and other organizations

Study Shows Melatonin Supplements May Make Standing A Hazard For The Cardiovascular-challenged

Date:
September 16, 2003
Source:
Penn State
Summary:
A study by Chester A. Ray, Ph.D., associate professor of medicine, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center suggests that melatonin supplements may make symptoms worse for the half a million people – many of them women and the elderly – with orthostatic intolerance, a condition in which the cardiovascular system cannot maintain adequate blood pressure and blood flow to the brain when a person stands, causing dizziness and fainting.

For insomniacs and jet-lagged travelers, melatonin supplements may enable a good night's sleep.

However, a study by Chester A. Ray, Ph.D., associate professor of medicine, Penn State College of Medicine, Penn State Milton S. Hershey Medical Center suggests that melatonin supplements may make symptoms worse for the half a million people – many of them women and the elderly – with orthostatic intolerance, a condition in which the cardiovascular system cannot maintain adequate blood pressure and blood flow to the brain when a person stands, causing dizziness and fainting.

"Melatonin supplements can hinder nervous system responses that enable the body to compensate for the drop in blood pressure when a person moves from a seated to standing position," Ray said. The study titled, "Melatonin attenuates the sympathetic nerve responses to orthostatic stress in humans," was published in the Sept. 15 issue of the Journal of Physiology (London).

In addition to its use here on Earth, melatonin also is taken by astronauts in space, two-thirds of whom experience orthostatic intolerance immediately after touchdown on Earth.

"When astronauts return to Earth, there is a chance that, for safety reasons, they will need to make a quick exit from the spacecraft," Ray said. "This study suggests that taking melatonin supplements for sleep could exacerbate orthostatic intolerance, making them unable to evacuate the shuttle and compromising their safety."

Melatonin is a hormone made by the pineal gland in the brain and secreted at night on a circadian, or 24 hour, cycle, to make people feel sleepy. Available in synthetic form, dietary supplements of melatonin have been linked to improved sleep, prevention of jet lag, and more. Studies have shown that melatonin supplementation may reduce blood pressure and decrease blood plasma levels of norepinephrine, a neurotransmitter responsible for raising blood pressure.

For this study, 12 healthy volunteers were given either a three-milligram tablet of melatonin – a dose often used and available at nutrition stores – or a non-medicated placebo pill. Fifty minutes later, each volunteer was asked to lay down and place both legs in a lower body negative pressure (LBNP) chamber, a device that reduces pressure to the legs, mimicking the effect of a person standing up. Ray used microneurography to record the sympathetic nerve activity to the blood vessels of the muscles. Sympathetic nerve activity starts a chain reaction that causes the blood vessels to constrict, increasing blood pressure and ensuring adequate blood flow reaches the entire body. After taking measurements at rest, the pressure in the LBNP was decreased and all measures were again taken.

To see if melatonin had an impact during other forms of physical stress, volunteers underwent a handgrip exercise test and a cold pressor test where a hand is placed into ice water for a short period of time. These tests also were done on two separate occasions, once after taking the melatonin supplement and taking a placebo.

Results showed that nerve activity under orthostatic stress (LBNP) was reduced in those volunteers who had taken melatonin compared to those who had taken placebo. Nerve activity was not affected in volunteers who had taken melatonin who underwent the handgrip or cold pressor tests.

"This finding suggests that melatonin has specific physiological effects, namely, decreasing nerve activity, when someone stands, but not necessarily during other types of physical activities," Ray said.

Additional studies will investigate whether melatonin decreases orthostatic tolerance in women, elderly and astronauts.

###

This research was supported by grants from the National Institutes of Health, National Aeronautics and Space Administration, National Space and Biomedical Research Institute, and American Heart Association. The study was approved by the Institutional Review Board of the Penn State College of Medicine and conducted at the Medical Center's National Institutes of Health-funded General Clinical Research Center.


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Cite This Page:

Penn State. "Study Shows Melatonin Supplements May Make Standing A Hazard For The Cardiovascular-challenged." ScienceDaily. ScienceDaily, 16 September 2003. <www.sciencedaily.com/releases/2003/09/030916073900.htm>.
Penn State. (2003, September 16). Study Shows Melatonin Supplements May Make Standing A Hazard For The Cardiovascular-challenged. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2003/09/030916073900.htm
Penn State. "Study Shows Melatonin Supplements May Make Standing A Hazard For The Cardiovascular-challenged." ScienceDaily. www.sciencedaily.com/releases/2003/09/030916073900.htm (accessed July 30, 2014).

Share This




More Health & Medicine News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Generics Eat Into Pfizer's Sales

Generics Eat Into Pfizer's Sales

Reuters - Business Video Online (July 29, 2014) Pfizer, the world's largest drug maker, cut full-year revenue forecasts because generics could cut into sales of its anti-arthritis drug, Celebrex. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Nigeria Ups Ebola Stakes on 1st Death

Nigeria Ups Ebola Stakes on 1st Death

Reuters - Business Video Online (July 29, 2014) Nigerian authorities have shut and quarantined a Lagos hospital where a Liberian man died of the Ebola virus, the first recorded case of the highly-infectious disease in Africa's most populous economy. David Pollard reports Video provided by Reuters
Powered by NewsLook.com
Running 5 Minutes A Day Might Add Years To Your Life

Running 5 Minutes A Day Might Add Years To Your Life

Newsy (July 29, 2014) According to a new study, just five minutes of running or jogging a day could add years to your life. Video provided by Newsy
Powered by NewsLook.com
Ebola Outbreak Poses Little Threat To U.S.: CDC

Ebola Outbreak Poses Little Threat To U.S.: CDC

Newsy (July 29, 2014) The Ebola outbreak in West Africa poses little threat to Americans, according to officials with the Centers for Disease Control and Prevention. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins