Study Points to Link between Pain and Fatigue

A new study performed at the University of Iowa examined the link between fatigue and pain. The two conditions seem to go hand in hand in conditions like chronic fatigue and fibromyalgia. Scientists have been looking for reasons why fatigue and pain are so interrelated, and this study offers a plausible explanation.

The researchers, who used mice in their study, discovered that a protein implicated in muscle pain acts together with testosterone (the male sex hormone) to provide some protection against muscle pain. This may be why so many more women than men are diagnosed with conditions that have both pain and fatigue at their core, such as fibromyalgia and chronic fatigue syndrome.

The researchers point to a protein known as ASIC3 as the culprit involved in muscle pain. In a study of mice, the researchers compared male and female mice; some had the ASIC3 protein and some did not. Levels of fatigue were measured after the mice underwent runs of an hour’s duration.

The result? Male mice that had the protein ASIC3 were less fatigued than the female mice that did not have the protein. Furthermore, male mice lacking the protein were found to be as fatigued as the female mice.
Female mice with the protein ASIC3 were provided with testosterone and were then found to be as resistant to fatigue as their male counterparts. Female mice lacking ASIC3 that were given testosterone showed no improvement in muscle strength.

What does this signify? Testosterone and ASIC3 protein channels work in conjunction to guard against muscle pain and fatigue. This helps to explain why more women than men suffer from pain and fatigue syndromes. The researchers believe that pain and fatigue share a common conduit that somehow becomes interrupted in conditions such as fibromyalgia and chronic fatigue. A greater understanding of this issue may lead to more effective treatments for both conditions in the future.

Source: University of Iowa (2008, April 9). Biological Link Between Pain And Fatigue Discovered. ScienceDaily. Retrieved July 3, 2010, from http://www.sciencedaily.com¬ /releases/2008/04/080407153037.htm