Fig. 2. Changes of body mass, plasma and urinary indices of hydration status during a 41-hour dehydration and rehydration protocol involving highly trained cyclists. Abbreviations: B, baseline state before testing; D, dehydration to –4% body mass; E, after cycling exercise to exhaustion; 4H, after 4 h of ad libitum rehydration; 21H, after 21 h of ad libitum rehydration. Reprinted from reference 20.