Fatigue In Women Is Reduced In Stress-related Cortisol Study

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Fatigue In Women Is Reduced In Stress-related Cortisol Study

http://www.sciencedaily.com/releases/2006/11/061113173640.htm

A study of healthy women has harvested results involving fatigue and

vigor that eventually may help researchers fine tune efforts to

treat a multitude of illnesses and syndromes linked to low levels of

the stress hormone cortisol.

That low cortisol levels are found in such maladies as chronic

fatigue syndrome, post-traumatic stress disorder, fibromyalgia and

atypical depression is not new. However, the study, published in the

November issue of Psychophysiology, combined with other findings

emerging from a comprehensive project, appear to support the idea

that sex hormones tend to separate men from women in their reactions

to stress, said Mattie Tops, a postdoctoral research associate in

the NeuroInformatics Center at the University of Oregon.

The study is the first to demonstrate improvements in fatigue and

vigor in healthy female subjects, a finding that " is particularly

relevant because of the high prevalence of hypocortisolemic fatigue

syndromes in women and the association in healthy women between low

morning cortisol levels and complaints of fatigue and muscular

pain, " Tops and his colleagues wrote in their conclusion.

In the study, 27 healthy women between the ages of 30-55, who met

certain medical criteria and agreed to certain restrictions in diet,

were given either placebos or capsules containing 35 milligrams of

cortisol during morning sessions. After reading or resting for 70

minutes, blood was taken for sampling. Then participants performed

an hour of computer-based tasks involving working memory, free

recall, recognition memory and selective attention.

During this time, fatigue increased and vigor decreased, but those

women who had received the cortisol reported a lesser increase in

fatigue and higher vigor than did the women receiving placebos. The

impact on fatigue levels was the most significant. The morning

testing coincided with the time period in which naturally occurring

cortisol levels are at their highest.

" In this study, we used healthy subjects who you wouldn't expect to

have low cortisol levels, " Tops said. " But fatigue is highly

prevalent in women. It was kind of surprising that we found this at

all. It may be a temporary effect of energy mobilization in

conjunction with the cortisol administration, but the findings that

cortisol ingestion provided positive results draw attention to those

syndromes that are characterized by low cortisol levels. "

The study was done in the Netherlands and is just one part of a

larger project being done by Tops, a native of the Netherlands, and

researchers at the University of Groningen and University Medical

Center Groningen. A larger, not-yet-published study by the

collaborators has found an association between low levels of

cortisol and reports of high fatigue in women.

Tops is exploring a variety of interconnections involved in low

cortisol levels, but not necessarily for the development of

difficult-to-deliver cortisol-based treatments because of a long

list of negative side effects that occur when levels are not

accurately regulated. Cortisol supplementation has helped in some

cases of post-traumatic stress disorder and chronic fatigue syndrome.

One issue that Tops and colleagues are seeking to address in some of

their studies is the possibility that a sex difference in stress

response is involved in hypocortisolemic syndromes. Some findings,

Tops said, fit in nicely with a study led by UCLA's E.

and published in Psychological Review in 2000. 's study

proposed that women have evolved to respond differently than males

to stress, adopting a " tend-and-befriend " reaction. Most studies

call major responses to stress as a fight-or-flight mechanism in

which hormones activate the nervous system for fighting for

territory or fleeing for safety.

and colleagues argued that almost all such studies have

involved male animals and men, and that women instead have

selectively evolved a mechanism to assure the survival of self and

children. To do so, women went about befriending others and forming

social groups to reduce risk. Hormonal responses, they argued, thus

have developed differently for men and women.

A key to treatment of low cortisol levels, Tops said, likely will

involve the development of pharmaceuticals that target specific

components involved in the interaction of various hormones in

various medical conditions.

Coauthors of the study were Tops, ien M. Van Peer of the

University of Groningen, University Medical Center Groningen and the

University of Leiden, Albertus A. Wijers of the University of

Groningen and Jakob Korf of University Medical Center Groningen. The

research was supported in part by the Netherlands Research

Organization.