Reichert ar200

For 24 h hydration status, each 24 h urine sample was assessed for urine volume (U_VOL) to the nearest 0.0001 kg using a digital scale (Ranger 2000, OHAUS Corporation, Parsippany, NY, USA), urine osmolality (U_OSMO) measured in duplicate using the freezing point depression method (Model 3320, Advanced Instruments Inc., Norwood, MA, USA), and urine specific gravity (U_SG) using a digital refractometer (Reichert AR200, Reichert Technologies, Buffalo, NY, USA).

From each 24-h urine sample, urine volume (U_VOL), and urine specific gravity (U_SG), U_VOL was measured on an electronic scale (Ranger 3000; OHAUS Corporation, Parsippany, NY, USA) to the nearest 0.0001 g, where 1 g was assumed to be equal to 1 mL of fluid. U_SG was measured using a digital refractometer (Reichert AR200; Reichert Technologies, Buffalo, NY, USA). Throughout the course of the experimental trial, U_VOL was measured immediately after fluid consumption (0 min) and every 60 min over the course of 240 min (60 min, 120 min, 180 min, and 240 min). Fluid retention was calculated by measuring the beverage hydration index (BHI) and based on prior work [11 (link)]; BHI was calculated by dividing the cumulative urine output of DW by the cumulative urine output of IB.

Hydration Status. For assessment of hydration status, each 24 h urine sample was measured for urine volume (U_VOL) using a digital scale to the nearest 0.0001 kg (Ranger 3000, OHAUS Corporation, Parsippany, NY), urine osmolality (U_OSM) performed in duplicate using freezing point depression (Model 3320, Advanced Instruments, Inc., Norwood, MA), urine specific gravity (U_SG) (Reichert AR200, Reichert Technologies, Buffalo, NY), and urine color (U_COL) [29 (link)]. For the purposes of this manuscript, euhydration was defined as a U_OSM < 500 mOsm∙kg⁻¹ [23 (link)], U_SG ≤ 1.012, and U_COL ≤ 4 [30 (link)].
Body Composition. Nude body mass was measured to the nearest 0.1 kg using a digital scale (WB-800S Plus, Tanita Corporation, Tokyo, Japan) and height was measured to the nearest 0.1 cm using a wall-mounted stadiometer (Model 216, Seca, Chino, CA, USA). Body density was measured using the methods established by Jackson and Pollock [28 (link),29 (link)]. The average of two skinfold measures (Lange Skinfold Calipers, Beta Technologies, Santa Cruz, CA) taken across three sites on the right side of the body were used; measures were taken at the chest, abdomen and thigh for men [31 (link)] and suprailiac, triceps, and thigh for women [32 (link)]. Body fat percentage was estimated using the method established by Siri [33 ].