At baseline , hot flashes contributed most strongly to poor sleep ( correlation coefficient r = -0.525 , P < 0.0001 ) , somatic symptoms such as muscle pains ( r = -0.348 , P < 0.0001 ) , menstrual cycle-resembling complaints ( r = -0.304 , P < 0.0001 ) , anxiety and fears ( r = -0.283 , P < 0.0001 ) , decreased memory and concentration ( r = -0.279 , P = 0.001 ) , and sexual behavior ( r = -0.174 , P = 0.035 ) .