You may feel more steady on your feet with fibromyalgia one day, while your movement can be way off-balance the next day. When clumsiness strikes, your legs start clipping  the edges of furniture and your shoulders knock against the walls. It’s like being in a pinball machine, except you don’t get any bonus points for the extra bruises!

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.