One of the hard things about treating athletes and improving performance is attempting to assess their hydration status on a daily basis. This research shows that using osmolarity and conductivity of first urine could provide a simple and reliable way to assess hydration. Although this study used a relatively small sample size it appears promising for those of us in the performance field.
Reference: Med Sci Sports Exerc. 1998 Nov; 30(11):1598-602
