What makes your fibromyalgia body more wobbly some days than others? According to a study by Nuray Akkaya, M.D., and his research team in Turkey, your quality of sleep the night before plays a major role in how well you navigate movements the next day.* But sleep was not the only factor he found that was related to the potential for balance mishaps in people with fibro.

Akkaya compared the postural stability (e.g., balance) of 48 fibromyalgia patients and 32 healthy controls. The body mass index, which is a relative indicator of excess weight, was the same for both groups. The average age was also the same for each group (around 34 years old), so the participants were quite young. No one was on a sedating medication or a drug that might interfere with postural stability testing.

A balance testing system was used to produce a value for the relative fall risk for each person in the study. The fall risk computed for the fibromyalgia group was double that of the healthy control group.

Subjects stood on a platform that measured the relative pressure exerted by each foot when they were asked to modify their standing position, such as neck turned to the right or eyes closed. A person challenged by these simple changes will have more postural sway, meaning one foot presses down harder on the platform. It sounds easy, but many fibromyalgia patients found these tasks to be difficult.

Obviously, a person’s leg function can help keep a sturdy, upright posture when changing positions. Each participant’s lower-body muscle strength was measured along with their ability to stand on one leg. Questionnaires were used to assess various symptoms, such as pain, fatigue, and overall function.

“Postural performance was worse in the fibromyalgia patients compared to the control subjects and it was related to the severity of fatigue and sleep quality in the last 24 hours,” says Akkaya. “Fall risk was found to be related to lower-body strength and scores for the one-leg stance test.” However, the duration of fibro, rating of pain, overall function, and quality of sleep for the past week (not just the previous night) were NOT related to balance in the fibromyalgia patients.

Although all subjects with vestibular-related symptoms, such as ringing in the ears and dizziness, were excluded from the study, vestibular system abnormalities were still detected in the fibromyalgia group. In addition, the sensory signals from the feet (which inform the brain about your stance) and postural reflexes also might contribute to balance disturbances.

“There is no single mechanism that can account for postural instability in fibromyalgia patients,” says Akkaya. However, he points out that warm water therapy improves muscle strength and balance in fibro patients, which is consistent with his finding that reduced leg strength increased risk of falling. So improving lower body function (perhaps with a walking program) and the quality of sleep (using drug and nondrug approaches) should make you more steady on your feet.

* Akkaya N, et al. Assessment of the relationship between postural stability and sleep quality in patients with fibromyalgia. Clin Rheumatol [epub ahead of print] Nov. 21, 2012.

Milunovic points out there is a major problem with the definition of pain as “an unpleasant sensory and emotional experience.” Adding to this vague definition that is largely useless to the practicing physician is the 1990 fibromyalgia criteria put forth by the American College of Rheumatology (ACR). It says fibromyalgia is present in a person who has tenderness in at least 11 of the 18 defined tender point areas. That definition is all about pain and says nothing about the other baffling symptoms you have such as fatigue, sleep disorder, or trouble concentrating (e.g., fibro fog).

“The new 2010 ACR criteria somewhat reduce the importance of tender points while concentrating more on other features,” says Milunovic. “The primary aspects newly introduced are fatigue, cognitive problems and waking without feeling rested. Secondary aspects include symptoms varying from irritable bowel disease to dizziness and nervousness.”

On the surface, this new criteria may seem more likely to pick up the specific types of symptoms you have besides the pain, but it falls short as well because it just generates a number ranging from 0 to 12. “This approach attempts to collapse symptoms into a globally perceived measure of dysfunction,” says Milunovic. Condensing your symptoms and their severity to just a number may be useful for following your progress in a clinical trial, but doesn’t help your doctor pinpoint specific symptoms that deserve priority treatment.

“Being able to identify key symptom clusters may reflect significant individual variability,” says Milunovic. In other words, not all fibromyalgia patients are alike, nor should they be treated that way. He goes on to suggest, “Measurement of this variability may allow for more individualized therapeutic strategies.” After all, when you go to the doctor, don’t you want to be treated for your individual complaints, rather than a number or score obtained through tender point counts or a symptom tally?

“We may be missing or mixing subpopulations of fibromyalgia patients with distinct neurobiological or behavioral characteristics,” notes Milunovic. By ignoring the subgroups of fibromyalgia patients and applying cookbook treatment guidelines by various professional pain associations, he adds that “the use of personalized medicine in research and clinical practice remains only a remote possibility.”

While most researchers in the field of fibromyalgia acknowledge many subgroups or varieties of this disease, patients with highly variable characteristics are excluded from clinical trials. So the published trials your doctor may be relying upon for treatment guidance might not apply specifically to you. Milunovic suggests various scientifically sound yet cheaper assessment tools, such as multi-probe brain electroencephalograms, be used in place of the expensive functional MRI tests to better define the various subgroups of fibromyalgia patients.

Implementing a uniform set of objective test measures to all patients and entering the findings into a massive database used by multiple countries is how Milunovic believes subgroups of fibromyalgia may be identified. He adds that the end goal is to enhance the effectiveness of treatments by enabling physicians to offer more personalized care specific to your particular set of symptoms.

* Bras M, et al. Psychiatria Danubina 23:246-250, 2001.

Using 44 women with fibromyalgia and 122 healthy controls, the researchers snipped hairs from the tops of heads, very close to the roots, to perform their analysis. Like crime scene investigators, the research team led by Nam-Seok Joo, M.D., carefully selected patients and controls with similar characteristics related to age, body mass, and lifestyle habits. Women with other illnesses that could possibly influence their hair sample were excluded from the study. All the participants, averaging 44 years of age, had to refrain from using hair gels, or applying any type of chemical processing (such as coloring or perms) for at least two weeks before the snip.

The clean hair analysis showed fibromyalgia patients had significantly lower levels of calcium, magnesium, copper, iron, and manganese. Many other minerals, such as chromium, selenium, potassium, phosphorous, sodium, and zinc, did not differ between the patients and controls.

Previous reports looking at mineral status in fibromyalgia patients have been mixed and often conflicting. Joo points to the inherent problem of these prior studies, which sampled blood or urine. The body is made to adapt to changing demands, such that many minerals are robbed from the bones to maintain sufficient blood levels. And alterations in the urine may not say much about the level of mineral storage in the bones or other tissues. However, hair analysis should provide a more accurate picture of the body’s overall mineral status.

“Several studies have explored the relationship between fibromyalgia patients and oxidative stress. Still other studies investigated elemental composition of patients, but they surveyed only blood and urine samples,” reported Joo. “The latter studies, while potentially useful, overlooked the mineral content of hair. The hair mineral assay is a good method to explore the mineral status at the cellular level.”

So what exactly does it mean to be low in the five minerals identified by Joo? More studies are needed, but Joo points out that several reports have shown that fibromyalgia patients lack the necessary antioxidants to neutralize reactive chemicals that can interfere with cellular functions. This, in turn, leads to an oxidative stress environment and could account for symptoms involving muscles spasms and cramps, fatigue, neuromuscular weakness, and insomnia.

While it is not practical to start taking a whole barrage of expensive mineral supplements, fibromyalgia patients should consider taking a daily broad-spectrum multivitamin and mineral supplement that contains 100 percent of the essential nutrients including iron.

* Kim YS, et al. J Korean Med Sci 26(10):1253-7, 2011.

Sustained muscle contractions are known to trigger the release of pain-relievers into the spinal cord to reduce feelings of achiness in those muscles that are getting the workout. It’s a natural process that soothes pain, at least in healthy subjects. But this system that provides analgesia after exercise appears to be working the wrong way in fibromyalgia patients.

Study participants were asked to contract the large shoulder muscles in their upper back until their muscles gave away to fatigue. Twenty-two fibro patients were compared to the same number of healthy control subjects. Everyone in the study was middle-aged, so age was not a factor.

The upper shoulder muscles’ sensitivity to pressure pain was measured before and immediately after the contraction, as well as 20 minutes later. Pain sensitivity was also checked in a lower leg muscle that was relaxed the entire time. The research team predicted that the spinal cord was misinterpreting the messages from the contracting muscles and making pain worse throughout the body in people with fibromyalgia.

The brief muscle contraction in the healthy group produced less pain in the shoulder area right after the exercise and 20 minutes later. This is what should happen when taxing one’s muscles, so that waste products like lactic acid don’t leave people hurting. If this did not happen, people would learn to avoid exercise whenever possible and that wouldn’t be healthy. Pain sensitivity in the lower leg was unaffected. The results were quite the opposite for those with fibro.

Pain levels started out much higher in the group of fibromyalgia patients (as expected). In addition, the spinal cord did not kick in to relieve post-exercise soreness in the shoulders. Worse yet, pain sensitivity increased significantly in the leg muscles that were relaxed throughout the study.

What does this mean? The system in the spinal cord that people rely upon to ease post-exercise discomfort seems to be responding to workouts by increasing the pain in fibro. So, if you are a fibro patient on your feet all day long, your activity can cause sore leg muscles and also make other muscles hurt, such as those in your arms.

Exercise is an essential part of staying fit and healthy, but it is hard to do if it increases your pain, as this study demonstrates. The trick is to not overwork any of your muscles. This explains why fibromyalgia patients state that keeping their pain under control requires frequent rest breaks and changing positions to avoid straining any muscle group.

Increasing physical function has to be done extraordinarily slow in fibromyalgia patients just to keep the pain levels stable. As your muscles get bigger and stronger, your body will be able to sustain more activity before the spinal cord decides to amplify your pain. Improving fitness has to be done very carefully and gradually, or increased muscle aches will constantly trip you up (unlike those healthy folks who feel great after a heavy workout).

* Ge HY, et al. Descending pain modulation and its interaction with peripheral sensitization following sustained isometric muscle contraction in fibromyalgia. Eur J Pain 16(2):196-203, 2012. (Available online ahead of print June 28, 2011.)

]]> http://www.fmnetnews.com/latest-news/keeping-your-body-aches-under-control/feed 57 http://www.fmnetnews.com/latest-news/disease-severity-markers http://www.fmnetnews.com/latest-news/disease-severity-markers#comments Fri, 29 Jul 2011 21:20:16 +0000 joshua@fmnetnews http://newsite.fmnetnews.com/?p=1934 Wouldn’t it be wonderful if doctors could order a blood test to see how well a therapy is doing, or document that a drug is not working? Better yet, you could have objective proof of your pain severity instead of your lab work making you look perfectly fine. Several blood markers have been identified in fibromyalgia patients, and the results are being refined by Alan Light, Ph.D., of the University of Utah, in hopes that they will produce a diagnostic blood test. Light also suspects he will be able to identify many subgroups of fibromyalgia.

The work by Light is absolutely exciting, but a diagnostic blood test could take years. In the meantime, Dennis Ang, M.D., and his team at Indiana University, are looking at the potential for a quick, rather simple lab test for objectively measuring disease severity. In particular, his goal is to document the pain levels in people with fibromyalgia.*

Part of the difficulty with developing blood markers for fibro is that most of the action is occurring within the nervous system and the blood often does not reflect these changes. So Ang is looking for surrogate markers in the blood that might tell doctors how the central nervous system is working in people with fibromyalgia.

Plenty of research evidence shows that painful inputs from all over your body and multiple muscles place your central nervous system on high alert. This bombardment of inputs leads to a system where the concentration of pain transmitting chemicals builds up, such as substance P (SP) and corticotrophin-releasing hormone (CRH). In fact, both SP and CRH are elevated in the spinal fluid of people with fibromyalgia. As a result, the nervous system becomes sensitized to future painful inputs. Instead of toning down the pain signals, the nervous system magnifies them (e.g., making you feel worse, not better).

So why don’t researchers and treating physicians just order a blood test to measure your levels of SP and CRH? While these chemicals are at least double what they should be in the spinal fluid of people with fibromyalgia, their values in the blood are normal. This is the hurdle that researchers have been stumbling over because many factors are clearly abnormal in the nervous system in people with fibro. Yet, spinal fluid measurements are only done in research studies and such techniques are simply not available for treating physicians.

Ang’s team is testing a method to take a peak at what is happening inside the nervous system by testing two substances in the blood that may be caused by elevations in SP and CRH (both elevated in fibromyalgia). A simple diagram of how this new test might work is shown below. Basically, elevated SP and CRH causes an activation of mast cells that are located all over your body, leading to enhanced release into the blood of two immune system chemicals or chemokines: IL-8 and MCP-1.

Exactly what IL-8 and MCP-1 do in the body is not nearly as important as just knowing that previous research has shown them to be elevated in the blood of fibromyalgia patients. If these two substances correspond to how well you are doing, then their concentration should decrease with improvements in pain ratings. On the other hand, if pain scores get worse, then their levels ought to increase. At least, this is how markers for measuring your disease severity should work.

One way to check if these two markers are able to pick up changes in fibro pain is to measure them before and after a treatment trial (i.e., the longitudinal measurement of treatment effects over time). Ang put a small group of fibro patients through a six-week course in pain and stress management while not changing any medications used.

Improvements in fibro pain corresponded to reductions in both IL-8 and MCP-1. The results are only preliminary, but offer hope that objective disease severity markers can be developed for fibromyalgia.

“While our study does not implicate a cause-and-effect relationship, the longitudinal associations of fibromyalgia pain severity with blood concentration of IL-8 and MCP-1 raise the question that these two chemokines may be involved in the pathogenesis of fibromyalgia,” writes Ang. “If our findings are replicated in a larger group of patients, IL-8 and MCP-1 may facilitate the prediction of prognosis and monitoring of treatment response in the future.”

* Ang DC, et al. Pain Med [epub ahead of print] June 30, 2011.

Research during the past year shows that fibromyalgia patients have many muscles with tight, rope-like bands containing firm knots called myofascial trigger points.^2,3 These trigger point areas hurt even when a person with fibromyalgia is resting. And when pressed, they also radiate pain to other muscles.

Osteoarthritis or trauma to a joint is another source of discomfort, besides trigger points, that may occur in people with fibromyalgia. One population-based study in Sweden found that joint pain was seven times more common in fibromyalgia patients than the rest of the nearly 45,000 individuals who were screened for health conditions.⁴

Based on the high incidence of trigger points and joint pain, Maria A. Giamberardino, Ph.D., and her team at Chieti University in Italy, designed a study to find out if effectively treating one nagging trigger point or painful joint would effect the overall impact on the body-wide pain of fibromyalgia. Only one area, a trigger point in the shoulder or a bothersome joint, was relieved of pain using regional techniques applied to the selected area. 

A series of two to four injections with anesthetic was used to treat a trigger point in one group of fibromyalgia patients. For the group of patients whose focus was pain in one joint, a combination of two anti-inflammatory medications were applied topically to the area with the aid of a tiny electrical current to help the drugs penetrate the tissues. Treatment effects after 30 days were compared to fibromyalgia patients with similar local pains that received placebo therapies.

Treating either the trigger point or the joint in the two groups of fibromyalgia patients led to a substantial reduction in pain at the local area addressed. In addition, the patients who received treatment, compared to those in the placebo group, reaped a 20 to 30% reduction in body-wide discomfort. This was assessed by an examiner who was unaware of which group (trigger point, joint pain or placebo) the patients belonged to.

“Local treatment of the peripheral muscle/joint sources not only relieves local symptoms but also significantly improves the widespread fibromyalgia symptoms,” write Giamberardino and coworkers. More specifically, they state that diffuse pain and tenderness throughout the body was greatly improved by addressing just one area.

Giamberardino suggests that the first step in treating fibromyalgia might be to target trigger points, painful joints, and other similar conditions that hurt. She points out that this could lead to a lower dose of oral drugs, minimizing the side effects that they tend to cause for patients.

Alternatively, she notes the addition of local treatments plus orally-administered medications that work systemically “could lead to better symptom control at the same doses, with obvious advantages for the patients. This is particularly important for a syndrome like fibromyalgia where management options available so far are still of limited effectiveness in a large percentage of cases.”

Three medications are currently FDA-approved for treating fibromyalgia pain (Lyrica, Cymbalta and Savella), but they only provide mild pain relief for roughly one-third of patients.⁵ This study shows that treatment of regional areas that hurt (such as trigger points or joints) with a variety of topical and nondrug therapies may be well worth the effort to achieve better control over fibromyalgia symptoms. There are also many self-help approaches that you may find beneficial.

1. Affaitati G, et al. Eur J Pain [Epub ahead of print] Oct.1, 2010.
2. Ge HY, et al. PAIN 147(1-3):233-40, 2009.
3. Ge HY, et al. J Pain 11:644-51, 2010.
4. Kato K, et al. Arch Intern Med 166:1649-54, 2006.
5. Hauser W, et al. J Pain 11:505-21, 2010.

“The presence and severity of a particular symptom may not necessarily equate with patients’ preferences for its treatment,” write the authors Robert M. Bennett, M.D., of Oregon Health and Sciences University, and I. Jon Russell, M.D., Ph.D., of the University of Texas at San Antonio. So this new study took a different approach. More than 750 fibromyalgia patients enrolled in a multi-center treatment trial for Lyrica agreed to also rank the top five symptoms (from a list of 20) that they would like to have treated. The list of 20 symptoms was developed by a previous research study involving fibromyalgia patient focus groups who were asked to describe their most relevant clinical features or symptoms.

Due to the large number of patients involved in this study, researchers were able to apply statistical programs that mathematically determined which symptoms were most likely to cluster together. As a result, six cluster categories were identified: pain, fatigue, domestic, impairment, affective (mood-related), and social. Each individual cluster group and specific clinical features that tended to occur most related to one another (out of the 20) are shown in the table. As you will note, symptoms in the pain cluster were endorsed by the patients almost as frequently as those in the fatigue category (they differ by only 1%).

If you are wondering why disturbed sleep is in the pain (rather than fatigue) cluster, it is because the statistical analysis found pain and sleep to be more closely related. A patient who endorsed “disturbed sleep” was found to be 2.4 times more likely to also have endorsed “pain or discomfort” in their top five symptom treatment priorities.

“While pain and sleep have been suggested to have a reciprocal relationship in chronic pain conditions including fibromyalgia,” write the authors, “our results raise the question as to whether pain causes disturbed sleep or pain is a result of disturbed sleep.” Yet, difficulty thinking or fibro fog clustered with symptoms of fatigue when it came to patients ranking their treatment priorities. In other words, a person wanting their fatigue to be treated was also more likely to request that attention be given to their fibro fog.

Although the symptoms contained in the pain and fatigue clustered were virtually equal in terms of treatment priority for the group of 750 fibromyalgia patients, this was not the case for the other symptoms. “The psychosocial clusters were not considered to be as high a priority,” write Bennett and Russell, adding that greater than 70% of the patients did not even rank the symptoms listed for these categories in their top five treatment priorities.

The many symptoms of fibromyalgia can certainly complicate the treatment of people with this disease and it would be beneficial for doctors (and their patients) if they could subgroup each patient according to how they rank the treatment of symptoms. As illustrated by this study, patients who want their pain treated will also probably want their physician to help with improving sleep. Patients who rank fatigue as the top symptom that they want treated will probably also want their fibro fog addressed.

“Understanding the full complexity of the clinical features of fibromyalgia is becoming increasingly important with the availability of newer pharmacologic therapies that have significant effects on pain and other clinical features, such as sleep (Lyrica and Xyrem), affective symptoms (Cymbalta), and fatigue/fibro fog (Savella),” write Bennett and Russell. As more studies like this one become published, the next step will be apply multi-drug therapies to target specific symptom clusters to determine how well subgrouping patients can improve their overall care.

* Bennett RM, et al. BMC Musculoskeletal Disorders 11:134-143, 2010.

As estrogen levels start to decline in peri-menopause and hit rock bottom in menopause, this triggers symptoms that could go untreated and might make your fibromyalgia worse. For example, the sleep complaints are very bothersome for peri-menopausal women, yet sleep studies have failed to find evidence of disturbed sleep when comparing pre-, peri-, and post-menopausal women. But what about comparing peri-menopausal women who have significant symptoms to those with very minimal symptoms? This was the basis for a research study presented at the annual SLEEP conference in San Antonio, TX, June 6-9, 2010.¹

The study was very small, comparing only six women in the symptomatic group to six in the mild symptom group (i.e., controls), but here are a few of the trends that the University of Melbourne researchers identified:

• Women in the symptomatic group had higher daytime sleepiness compared to the controls. Two validated questionnaires were used and both showed that symptomatic women are very sleepy.
• Symptomatic women spent less time in bed than controls; the difference was almost an hour.
• Women with lots of symptoms received less deep-level (stage 3 and 4) sleep compared to the controls. This difference was not highly significant and may go unnoticed by most sleep labs because when the overall sleep efficiency was calculated for the two groups, the results were the same.
• The sleep in symptomatic women may not feel as refreshing or restorative as it used to be because this group of women has less parasympathetic nervous system activity during sleep. Remember, the parasympathetic system is responsible for “rest and digest” functions that should dominate during nighttime sleep. Unfortunately, this system’s activity is not normally measured during a standard sleep study (e.g., it is mostly used for research).

A much larger study involving 35 post-menopausal women who were estrogen deficient (i.e., not on hormone replacement) was presented at the same conference and the findings expand upon those in the previous study.² The average age of the women was 54 and their overnight polysomnographic measurements revealed:

• Average time to fall asleep was 25 minutes and the time spent awake after having fallen asleep was 52 minutes.
• The average number of arousals during the night was 50, which helps explain why much time is spent awake.
• The women obtained an average of only 10 minutes a night of deep-level (stage 3 and 4) sleep. This value should be closer to 45 minutes, so post-menopausal women without estrogen are truly missing out on the restorative phase of sleep. It’s also the stage of sleep that causes the release of growth hormone for repairing the tissues so this hormone may be significantly less as well.
• The calculated sleep efficiency for the group of women was 85%. This is the cut-off for being scored as “normal” by most sleep centers, and shows how deceiving this value can be.

If your sleep is unrefreshing, whether you are an estrogen-deficient women experiencing menopausal symptoms or you are a person with fibromyalgia, a sleep study could be helpful. However, make certain that the sleep center pays special attention to the time spent in deep-level sleep and the number of arousals. The sleep efficiency of fibromyalgia patients is often graded as normal, but the actual components of your sleep could be greatly disturbed.

1. Baker F, et al. SLEEP Volume 33, Abstract 074 A28 Supplement 2010.
2. Davis E, et al. SLEEP Volume 33, Abstract 619 A208 Supplement 2010.

In April of 2010, the ACR revealed their new diagnostic criteria.* Posted by the Fibromyalgia Network website on April 14, they caused quite a stir among patients and the general public.

The ACR hopes these new criteria will make it easier for doctors to diagnose the illness. Patients and others who responded to the survey offered mixed reviews. Doctors who developed the new criteria are hoping to standardize the process so all physicians can use the same procedures. They also did away with the tender point criteria, as it did a poor job of measuring symptom severity or charting the effectiveness of new treatments. These objectives are important since most fibro patients are being diagnosed and treated by rheumatologists and family practitioners or primary care physicians.

In the Fibromyalgia Network survey, almost all (97%) of the individuals responding were officially diagnosed with fibro or at least strongly suspected they have the illness. Of the 9,946 people responding, 51% (5,084) were diagnosed by a rheumatologist, and 17% (1,736) were diagnosed by their primary care physician/family doctor. Professionals who are at the forefront in providing ongoing treatment, however, are primary care physicians (37%) followed by rheumatologists (22%). The next closest type of doctor primarily in charge of your current fibromyalgia treatment are pain specialists at a mere 7%.

While nearly half of those responding to the survey felt the new criteria gave a fair and reasonable assessment of symptoms, patients gave us a whopping 3,400 comments debating the pros and cons.

One of the more popular critiques of the new diagnostic criteria told us that patients were confused when they were asked to answer questions based on “how they felt over the past week.” However, one of the three major criteria in scoring instructions state that “symptoms be present at a similar level for at least 3 months.”

“I think it is misleading that the Symptom Severity Score only is applicable to the ‛past week.’ If a person just had a good week, as I sort of did, then the score is lower than if they just came through a bad week, like I had the week before. The Symptom Severity Score should perhaps be the average of four (or more) weekly tabulations to be more accurate,” suggests one individual. Other patients commented that they experience more severe symptoms or flares through weeks or months, then followed by periods of less pain and symptoms, which could undermine a proper diagnosis.

More detailed information on the survey results including how many patients were actually diagnosed using the new tool will be printed in the July 2010 issue of the Fibromyalgia Network Journal. Read what the treatment experts have to say about the new criteria. Will they be using it, and do they think this checklist-type criteria will help the front-line physicians take on the challenge of diagnosing fibromyalgia? How helpful and accurate do they suspect the new criteria will be? Most importantly, how will these new guidelines affect your care and the image of fibromyalgia?

If you have not seen the new criteria, you are welcome to Take the Survey and offer your own comments.

* Wolfe F, et al. Arthritis Cares & Research 62:600-610, 2010.

Dane B. Cook, Ph.D., at the University of Wisconsin in Madison, says there is a “dearth of experimental research directed at pain” in GWI, but he suggests that “insight can be gained from research on civilians with fibromyalgia.” Cook says that there are some differences between the Gulf veterans with chronic pain and people with fibromyalgia. Most predominately, GWI tends to occur in men exposed to the chemically harsh environment of war, while those with fibromyalgia are mostly women whose symptom onset is highly variable but not war-related. What causes or triggers the onset of these two conditions may differ, but what sustains the pain in GWI and fibromyalgia may be very similar processes, according to a series of experiments by Cook.¹

Brief and vigorous exercise in healthy young individuals is known to lead to reduced pain sensitivity, often referred to as the “runner’s high.” However, the opposite occurred in people with fibromyalgia who were asked to ride 30 minutes on a stationary bicycle.² Cook proposed that veterans with GWI who also had widespread pain similar to fibromyalgia would rate a 30-minute bout of submaximal bicycling exercise as more intense, more painful, and would be more sensitive to pain stimuli when compared to healthy veterans who also served in the first Persian Gulf war. Both groups were physically fit when they were deployed, but upon their return, the GWI group had many unexplained symptoms, including widespread pain.

The recruitment of male research participants who served in the first Persian Gulf war was based on whether they had widespread pain that could not be explained by another illness (such as rheumatoid arthritis). Veterans with regional pain and injuries were also excluded from the study along with rheumatoid arthritis and similar diseases. Eleven participants were classified as having GWI with unexplained widespread pain and 16 met the criteria for the healthy controls.

“Despite exercising at a lower power output, Gulf veterans with chronic musculoskeletal pain still became more sensitive to experimental pain stimuli postexercise,” states Cook and colleagues. Leg muscle-pain intensity ratings increased throughout the exercise bout in both groups, but the GWI group with chronic widespread pain reported higher pain ratings that ramped up at a faster rate than the healthy group.

“A significant number of military personnel are no longer able to perform their duties due to multiple symptoms including pain, fatigue, and cognitive troubles,” writes Cook. He emphasizes that pain is just one of three factors describing GWI, but considering the lack of experimental data on this condition, Cook adds, “we modeled the design of the present study on similar research conducted in fibromyalgia.” The reasons for this are rather straightforward. Psychophysical testing of experimental pain in fibromyalgia has provided strong evidence of abnormal pain processing and now establishes a foundation for future studies that are likely to produce more evidence of abnormal functioning in GWI.

Based on findings in fibromyalgia, the present study suggests a failure of the pain regulatory system in the spinal cord. This would be expected to lead to increases in naturally occurring muscle pain during exercise and exaggerated central nervous system sensitivity following exercise. Repetitive stimulation of the painful sensory receptors in the peripheral muscles during physical exertion is likely the mechanism by which the chronic musculoskeletal pain is maintained in GWI. This is a similar phenomenon observed in a predominantly female population of fibromyalgia patients.

“Exercise research in chronic muscle-pain patients has brought an interesting paradox to light,” writes Cook. “Acute exercise appears to exacerbate pain while chronic exercise can reduce pain and improve other symptoms associated with chronic pain.”

Last year at the American Pain Society meeting, Cook demonstrated that mild bicycling at an easy level of resistance produced improvements in pain for people with fibromyalgia. More recently, Kevin Fontaine, M.D., of Johns Hopkins University, showed that a prescription for 30 minutes of “lifestyle physical activity,” or LPA, up to five days per week significantly reduced pain and improved overall function compared to a group of fibromyalgia patients who attended a series of educational sessions. Daytime fatigue scores and mood remained unchanged for both groups.³

The subjects in the LPA group were instructed to incorporate five to seven bouts of additional daily activities, such as walking, taking the stairs instead of the elevator, housework, gardening, or anything else that gets them moving for a few minutes. The level or intensity of the activity should increase breathing demands but not so much that a person cannot hold a conversation. Initially, the patients began at 15 minutes per day of LPA and worked to 30 minutes by the fifth week (i.e., increasing 5 minutes per week). All subjects wore a waist-mounted pedometer to record the number of steps they took each day and to determine if patients were following instructions.

Before the study, fibromyalgia patients averaged 3,800 steps per day. At the end of the 12-week study, the LPA group increased to an average of 5,800 steps per day, representing a 54% increase. Unlike most treatment interventions involving exercise, the dropout rate for the LPA group was small (13%) and it was the same as the education group used as a comparison.

“One thing seems clear from the fibromyalgia literature,” writes Fontaine, “people with fibromyalgia have difficulty adhering to exercise. Indeed, in fibromyalgia clinical exercise trials dropout rates often nearly exceed 30%, suggesting that developing exercise interventions that can be sustained is perhaps as important a goal as finding the particular interventions that produce optimal benefits.”

1. Cook DB, et al. J Pain March 23 [Epub ahead of print] 2010.
2. Vierck CJ, et al. J Pain 2:334-344, 2001.
3. Fontaine KR, et al. March 30 Arthritis Care Ther 12(2):R55 [Epub ahead of print] 2010.