3 (2.0)* –2.0 (2.2) Plasma sodium (mmol/l) –0.6 (3.9) –0.9 (2.8) –1.3 (2.6) –2.6 (2.4)** Plasma potassium (mmol/l) –0.4 (1.7) –0.1 (1.0) –1.6 (1.1)** –0.0 (0.5) Plasma osmolality (mosmol/kg H 2 O) 2.8 (4.2) 2.4 (6.2) 1.8 (5.8) 1.4 (5.5) Urine specific gravity (g/ml) 0.006 (0.004)** 0.006 (0.006)** 0.006 (0.011) 0.010 (0.009)** Urine osmolality (mosmol/kg H 2 O) 279.3 (195.1)** 200.8 (342.4)* 114.2 (355.8)** 319.0 (326.9)** Urine potassium (mmol/l) 49.5 (39.0)** 11.5 (22.9) 15.9 (35.9) 39.3 (40.6)** Urine sodium
(mmol/l) –15.6 (37.5) –37.8 (46.0)** –30.1 (38.4)* –13.8 (70.3) K/Na ratio in urine 1.7 (0.7)** 1.7 (2.4)* 0.56 (0.7)* 1.7 (3.1) Transtubular potassium gradient 28.7 (14.1)** 14.6 (46.4) 13.5 (20.0)* 27.3 (23.7)** Glomerular filtration rate (ml/min) –17.2 (14.7)** –11.7 (9.8)** –6.8 (6.1)** –14.6 (14.2)** D Change LY2109761 (%) Parameter R1 R2 R3 R4 Haematocrit (%) 2.8 (8.0) –2.4 (6.1) –3.1 (4.8)* –4.8 (5.1) Plasma sodium (mmol/l) –0.4 (2.8) –0.6 (2.0) –0.9 (1.9) Selleckchem PD0325901 –1.8 (1.7)** Plasma potassium (mmol/l) –6.3 (27.8) –0.6 (22.9) –24.6 (14.1)** –1.0 (9.2) Plasma osmolality (mosmol/kg H 2 O) 0.9 (1.5) 0.8 (2.1) 0.6 (2.0) 0.5 (1.9) Urine specific gravity (g/ml) 0.7 (0.4)** 0.5 (0.6)** 0.6 (1.1) 1.0 (0.9)** Urine osmolality (mosmol/kg H 2 O) 57.6 (85.3)** 37.9
(161.2)* 38.4 (195.6)** 71.8 (185.1)** Urine potassium (mmol/l) 174.8 (458.2)** 22.9 (22.0) 56.3 (191.8) 106.2 (422.9)** Urine sodium (mmol/l) –26.5 (81.6) –46.0 (118.1)** –37.0 (36.1)* –14.6 (105.2) K/Na ratio in urine 359.9 (187.2)** 281.7 (327.6)* 148.7 (222.3)* 366.6 (347.9) Transtubular potassium gradient 417.7 (575.1)** 56.9 (1185.7) 192.7 (2133.5)* 176.6 (1196.2)** Glomerular filtration
almost rate (ml/min) –19.8 (14.7)** –14.1 (11.7)** –7.3 (6.7)** –16.8 (13.9)** Results are presented as mean (SD), *= p ≤ 0.05, **= p < 0.01. In four (26.7%) ultra-MTBers, body mass increased between 0.2 kg and 2.0 kg. In the remaining 11 ultra-MTBers, body mass decreased between 0.7 kg and 5.0 kg, indicating that five (33.3%) were dehydrated. Δ body mass was negatively and significantly related to race performance (r = -0.69, p < 0.001). Neither Δ body mass nor% Δ body mass were related to post-race plasma [Na+] or Δ plasma [Na+].