Muscle Pain and Aging

SUMMARY

Objectives: Pain complaints at the musculoskeletal level, especially in their chronic manifestations, increase with age. The objectives of this review article are to discuss the physiologic and pathologic factors that may contribute to changes in sensitivity towards muscle pain with aging.

Findings: Very few psychophysical studies have explored the physiologic changes in muscle sensitivity with age. The largest population study so far conducted would indicate a decrease in pain threshold [pressure and electrical stimuli], particularly in elderly men. The profile of this hypersensitivity runs parallel to that of an increased oxidative damage to muscle fibers documented with the aging process. The global prevalence of pathologic events potentially painful for the muscle increases with age. The increase, however, mostly regards primary muscle pain, e.g., myofascial pain due to trigger points from microtraumatic events, or muscle pain secondary to deep somatic structure involvement, e.g., referred muscle pain/hyperalgesia from osteoarthritic joints. In contrast, the same phenomenon is not observed for muscle pain secondary to visceral pathology–especially in its acute form–which, instead decreases with age. The extent of the pain symptom due to pathologic conditions does not increase proportionally to that of the underlying pathologic process, probably due to reduced reactivity of the elderly tissues towards inflammatory events [lesser capacity of producing algogenic substances].

Conclusions: The increased complaints of musculoskeletal pain with aging appear the result of a complex interaction between the physiologic process of aging, which seems to promote muscle damage and muscle hypersensitivity especially in the male sex, and the increased prevalence with age of most potentially painful pathologic conditions of the muscle itself or of other deep somatic structures. Future clinical and research efforts should aim at better understanding the pathophysiology of the increased pain in muscles in the elderly to help prevent not only the suffering to the patient but also the disabling consequences of the pain symptom at this level.

KEYWORDS:

• Muscle pain threshold
• oxidative damage
• elderly
• primary and secondary muscle pain/hyperalgesia