Age-related differences in the endogenous analgesic response to repeated cold water immersion in human volunteers.

Abstract

Recent animal studies using stress-induced analgesia have suggested a general age-related decline in endogenous pain inhibitory systems. The aim of the current study was to examine age-related differences in the magnitude of endogenous analgesia in human volunteers, using psychophysical measures of neuroselective electrical, and thermal CO(2) laser induced pain thresholds, before, immediately after and 1 h after repeated cold water immersion of the hand. Sensory detection thresholds did not differ between age groups indicating that the functional integrity of primary afferent sensory fibres appears to be intact in older people. Consistent with many previous studies, older adults required a h..