Researchers are trying to bring an end to pain from fibromyalgia (FM). As yet, clear answers have not been easy to come by. Neither rest nor exercise seem to bring relief from pain from fibromyalgia. However it seems that a combination of the two may ease things somewhat.
Exercise will generally cause an increase in pain both during and after the exercise session. Adding a rest period after the exercise though, resulted not only in noticeable relief from pain for some subjects with FM, but also in improved ability to move and range of motion.
"To further clarify these effects, we examined the effects of alternating exercise with rest on clinical pain and thermal/mechanical hyperalgesia of 34 FM patients and 36 age-matched healthy controls (NC)."
During the study, the subjects with FM experienced pain while exercising, but they had relief from pain when they rested afterward. The results might best be summed up by the old expression, "It feels so good when I stop."
None of the subjects with FM ended up in worse condition after exercise alternating with rest.
http://www.prohealth.com/fibromyalgia/library/showArticle.cfm?libid=15346&B1