Fig. 2

A Mean osmolality of the morning urine during the four days of normal intake of water (Days 1–4) and increased intake of water (Days 8–11) versus the mean values of the spot samples during the subsequent three days (Days 5–7 and 12–14, respectively). Each point represents one volunteer. B Same plot but for urine creatinine. C Relationship between the measured intake of water and the mean value of the spot urine osmolality samples obtained during the same 24 h. D Same plot but for urine creatinine