Abstract
Fibromyalgia (FM) is a common chronic disorder with chronic pain. FM generally affects all ages and occurs more commonly in women. The cause of FM remains undefined, but a number of factors suggest the cardiovascular system and the blood in particular as contributors to its occurrence and maintenance. Hemograms and other blood indexes often show high percentages of values at the 'normal', low, or high limits and several values outside of the 'normal' ranges. On the other hand, vessels regulate blood arrival to tissues depending on many internal and external factors. Both aspects can interfere with tissue oxygenation and then with the numerous consequences induced by hypoxia. In this narrative review, efforts were made to highlight factors that are potentially able to affect oxygen arrival in cells, as well as other factors related to blood elements that can play a role in the chronic pain experienced by FM patients. Data strongly indicate that most of the symptoms commonly present in FM patients can find their physio-pathological basis in the blood, suggesting blood-related interventions in these patients.