An elite athlete underwent physiological testing in an environmental control chamber to monitor water balance. In three separate trials, the athlete performed identical cardiovascular workouts of equal duration and intensity but under different environmental conditions and fluid replacement protocols.
Table 1 displays the environmental conditions, the volume of water consumed during each trial, and the relative urine output.
Table 1
| Protocol | Chamber temperature (∘C^\circ\text{C}∘C) | Fluid volume consumed (cm3\text{cm}^3cm3) | Relative volume of urine produced |
|---|---|---|---|
| X | 38 | 800 | (i) |
| Y | 18 | 800 | (ii) |
| Z | 5 | 3000 | (iii) |
Complete Table 1 by classifying the relative volume of urine produced under each protocol as lowest, intermediate, or highest.
Using your knowledge of homeostasis, explain why the athlete's kidneys produce a different volume of urine under Protocol X compared to Protocol Y.