A preliminary study suggests a physical basis for chronic fatigue in Gulf War veterans, which may involve a suppression of cardiovascular responses to stress.
"Our findings suggest that symptoms of illness in Gulf War veterans with chronic fatigue are linked to the circulation in a coherent and physiologically significant way," said lead author Arnold Peckerman, PhD, of the VA Medical Center, East Orange, NJ.
After the Persian Gulf War, many veterans reported chronic fatigue; memory, concentration, and sleep difficulties; muscle and joint pain; and headaches -- a pattern of symptoms resembling chronic fatigue syndrome, an illness with no known cause.
Peckerman and colleagues gave three tests to 51 veterans suffering from chronic fatigue and to 42 veterans who did not suffer from the syndrome. Two tests measured mental effort: completion of math problems and presentation of a videotaped speech. A third test was a physical test: researchers applied a plastic bag filled with crushed ice and water to participants' foreheads.
While all study participants had a normal physical response to the test involving the bag of ice, those with chronic fatigue had an abnormal physical response to the tests requiring mental effort, the researchers found.
The blood pressure of the veterans with chronic fatigue didn't rise during the mental tests as much as that of the healthy veterans -- even though both groups perceived the math and speech tests as stressful and challenging.
Also, the veterans with the most blunted blood pressure responses felt the most fatigue and were more disabled by their illness, the researchers found.
According to the researchers, high blood pressure is often emphasized as a bad thing, but blood pressure should rise to a certain degree as a normal and healthy response to stress. This response is needed to assure plentiful blood supply to the working brain and muscles.
The veterans with chronic fatigue appear to have a disconnect between cardiovascular stress responses (including blood pressure) and mental activities, suggested the researchers. This disconnect may result in the concentration difficulties and exhaustion experienced by some veterans.
The cause of the possible disconnect is not clear, but may involve an injury to brain areas involved in the regulation of cardiovascular activity, according to the researchers.
Peckerman and colleagues also pointed out another possible explanation for the blunted blood pressure responses of study participants with chronic fatigue. It is possible that these individuals were simply so fatigued that they were "disengaged" when they were completing the tests, and thus did not experience the same blood pressure increases as the others.
Since the tests were perceived as comparably stressful and challenging to all the study participants, this explanation is not entirely convincing, but it merits more study, according to the researchers.
As a next step in their research, Peckerman and colleagues are now conducting a new study that will determine the exact mechanism by which blunted cardiovascular stress responses may contribute to Gulf War-related chronic fatigue. "We hope that this new study will move us closer to understanding this illness and what can be done to effectively treat it," said Peckerman. According to Peckerman, these new experiments are just beginning, and Gulf War Veterans from the Northeast who are suffering from chronic fatigue and would like to participate can call a toll-free number 800-248-8005 for more information.
The results of the study were published in the July/August 2000 issue of Psychosomatic Medicine.
This research was supported by the U.S. Department of Veterans Affairs.
Psychosomatic Medicine is the official bimonthly peer-reviewed journal of the American Psychosomatic Society. For information about the journal, contact Joel E. Dimsdale, MD, at 619-543-5468.
Posted by the Center for the Advancement of Health http://www.cfah.org. For information about the Center, call Petrina Chong, pchong@cfah.org 202-387-2829.
Journal
Psychosomatic Medicine