Spanish researchers have shown that obesity effects on fibromyalgia symptoms may be mediated by patients’ cardiorespiratory fitness. Their work, entitled “The association of total and central body fat with pain, fatigue and the impact of fibromyalgia in women; role of physical fitness,” was published in the European Journal of Pain.

Fibromyalgia affects skeletal muscles causing fatigue, and physical and emotional pain. Obesity contributes to disease severity and the worsening of disease symptoms and quality of life. At the same time, physical fitness is associated with improved clinical outcomes and decreased pain sensitivity.

The research team wanted to understand the link between total and central body fat in fibromyalgia pain, fatigue and overall disease impact, defining the contribution of physical fitness in these processes. The study included a total of 486 women diagnosed with fibromyalgia with a mean age of 52.2 years. Total and central body fat of each patient was measured using bioelectrical impendence and waist circumference. Patients’ fibromyalgia impact, pain, fatigue, and overall fitness were determined using self-reported measurements, questionnaires, algorithms, and physical and mental tests.

Results showed that patients with higher levels of total and central body fat had increased pain, higher general and physical-related fatigue levels, and more severe disease consequences. With the exception of physical-related fatigue, all these outcomes were partially mediated by the cardiorespiratory fitness of each patient. Fibromyalgia mental fatigue levels were shown to be independent of total or central body fat levels, and of the overall physical state of patients.

These findings suggest that maintaining normal body fat levels and a good physical fitness might help to minimize some fibromyalgia symptoms and their severity. Nonetheless, the team could not establish whether a higher fitness level is a cause or a consequence of lower body fat levels, or a consequence of lower pain levels in fibromyalgia female patients. These issues should be addressed in future studies, which should also include men, to fully understand the implications of obesity and overall fitness in fibromyalgia maintenance.