Abstract
Many reports have shown that there are sex differences in pain sensitivity, and that hormonal condition also modulates pain sensitivity. In the last year we reported that pressure pain threshold (PPT) was higher in males (n=10) than females (n=20, 10 in follicular and 10 in luteal phase), that females in follicular phase had a higher PPT than those in luteal phase, and that there was no difference in the time course of PPT changes (delayed onset muscle soreness) after lengthening contraction (LC). To make the results more solid, we recruited 10 more males and 25 females with clear basal temperature cycle, and we repeated measurements in some of the females who participated in the previous experiment and had clear cyclic change in the basal body temperature, but in the different phase of their menstrual cycle from the previous experiment. We confirmed that PPT was significantly higher in males than in females as previously reported, and that female PPT was higher in the follicular phase than in the luteal phase. PPT decreased 1 day after LC in all three groups and returned to the pre-exercise value 3 days after LC in luteal phase females, and 4 days after LC in follicular phase females and males. Present results showed clear sex and menstrual cycle differences in muscle pain threshold. [J Physiol Sci. 2007;57 Suppl:S98]
