Urc ne

The first urine sample in the morning and the first urine sample after SC were taken from all the subjects. They were collected in polyethylene tubes previously washed with diluted nitric acid and frozen at −80 °C until analyzed, and once the container was handed over, it was measured and codified. Prior to analyses, samples were thawed and homogenized by shaking.
A 10 mL quantity was used to obtain the different evaluated parameters. Specific gravity was analyzed in situ with a precalibrated refractometer (URC-Ne, Atago, Japan), as previously described [32 (link)]. Biochemical variables (pH, microalbuminuria (MA), erythrocytes) were measured by placing a reagent strip (Combur Test, Roche, Spain) in a small portion of urine samples. Next, the strip was placed inside an automatic reflection photometer (Urisys 1100, Roche, Spain) to measure the parameters after a 1 min incubation time.

Core temperature was recorded via an ingestible radio-telemetric thermistor using a CorTemp Data Recorder 262 K device (CorTemp HQ Inc., Palmetto, United States; accuracy±0.1°C). Heart rate was measured continuously via a chest based polar monitor throughout the work-shift (Polar H7, Finland). Participants wore accelerometers (Actigraph GT3X, Pensacola, United States) on their hip. Data recorded continuously (epoch 30 Hz) during the shift and was downloaded using ActiLife (Actilife, version 6.13.4, Pensacola, United States). A hand-held refractometer (ATAGO Model URC-N_E, Japan) measured USG. Values for USG were defined as “well hydrated” <1.010, “minimal dehydration” 1.010–1.020, “significant dehydration” 1.021–1.030 and “serious dehydrated” >1.030 (Casa et al., 2000 (link)).