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. 2019 Aug 19;59(5):2171–2181. doi: 10.1007/s00394-019-02065-7

Table 2.

Water intake and corresponding markers of hydration

Baseline Water restriction
Day 1
Water restriction
Day 2
Water restriction
Day 3
Post-graded rehydration intervention
Total water intakea (mL day−1)
 CON 3382 ± 1286 1750 ± 277 1743 ± 260 1779 ± 335 1726 ± 297*
 G+0.50 3248 ± 941 1700 ± 345 1681 ± 300 1820 ± 419 2205 ± 342*
 G+1.00 3376 ± 1183 1721 ± 331 1784 ± 416 1758 ± 248 2676 ± 336*
 G+1.50 3684 ± 1621 1734 ± 465 1661 ± 315 1794 ± 490 3118 ± 291*
 G+2.25 2930 ± 989 1667 ± 250 1692 ± 260 1666 ± 188 3807 ± 184*
 Main effect of group 0.426 < 0.001
 Main effect of time < 0.001 < 0.001
 Interaction group × time 0.443 < 0.001
Body massb (kg)
 CON 75.8 ± 18.1 75.8 ± 18.5 75.8 ± 18.2
 G+0.50 71.7 ± 15.0 71.1 ± 14.5 71.3 ± 14.6
 G+1.00 79.8 ± 14.6 79.4 ± 14.3 79.3 ± 14.6
 G+1.50 70.8 ± 11.7 70.4 ± 11.7 70.4 ± 11.8
 G+2.25 68.4 ± 14.3 67.8 ± 14.0 68.3 ± 14.3
 Main effect of group 0.086 0.089
 Main effect of time < 0.001 0.063
 Interaction group × time 0.584 0.232
Urine osmolality (mOsm kg−1)
 CON 525 ± 291 810 ± 198 834 ± 223 873 ± 2263,4,5
 G+0.50 474 ± 218 729 ± 247 839 ± 222 704 ± 2544,5
 G+1.00 457 ± 205 700 ± 211 766 ± 255 613 ± 3151
 G+1.50 416 ± 226 783 ± 207 793 ± 240 502 ± 2501
 G+2.25 446 ± 219 769 ± 222 791 ± 268 452 ± 2841,2
 Main effect of group 0.681 0.004
 Main effect of time < 0.001 < 0.001
 Interaction group × time 0.881 < 0.001
Urine color
 CON 4 ± 1 5 ± 1 5 ± 1 6 ± 13,4,5
 G+0.50 3 ± 1 5 ± 1 5 ± 1 5 ± 15
 G+1.00 3 ± 1 5 ± 1 5 ± 1 4 ± 21,5
 G+1.50 4 ± 1 5 ± 1 6 ± 1 4 ± 21
 G+2.25 3 ± 1 5 ± 1 5 ± 1 3 ± 21,2,3
 Main effect of group 0.495 0.001
 Main effect of time < 0.001 < 0.001
 Interaction group × time 0.836 < 0.001
Urine-specific gravity
 CON 1.014 ± 0.007 1.021 ± 0.005 1.022 ± 0.006 1.023 ± 0.0064,5
 G+0.50 1.012 ± 0.005 1.019 ± 0.006 1.022 ± 0.006 1.019 ± 0.0065
 G+1.00 1.012 ± 0.005 1.019 ± 0.005 1.020 ± 0.006 1.016 ± 0.0071
 G+1.50 1.011 ± 0.006 1.021 ± 0.005 1.021 ± 0.006 1.014 ± 0.0071
 G+2.25 1.012 ± 0.006 1.020 ± 0.006 1.021 ± 0.005 1.011 ± 0.0081,2
 Main effect of group 0.648 0.003
 Main effect of time < 0.001 < 0.001
 Interaction group × time 0.411 < 0.001

All urinary measurements are from 24 h samples

1,2,3,4,5Wilcoxon rank sum post hoc test significantly different than CON, G+0.50, G+1.00, G+1.50, G+2.25, respectively

*Post hoc independent samples t test significantly different than all other groups at time point

aBaseline total water intake is average daily water intake over the 7 days of initial observation

bBody mass measurements occurred during the day. The body mass taken on the day of the graded rehydration intervention was only partially through the day; therefore, the body mass of the day after the graded rehydration intervention is reported here