Changes in 24-hour urine output (L/day) across the three study periods. Changes are shown relative to the very first collection (i.e., urine measurement 1, or M1). Individual values were calculated as a difference between the measured value at each of the 12 measurements and the measured value at M1. Values marked with an asterisk (*) differed significantly from the M1 reference value of zero liters (P < 0.05). Short dashed lines represent one-side SE bars.