Measuring Urine Specific for dehydration
Urine specific gravity measures
Each player provided a urine sample prior to each match for analysis. Specific Gravity is measured from a 2 mL urine sample using a calibrated handheld refractometer as in pic below. Staff members responsible for fluid distribution are notified of any player with Usg >1.020 mg/L. ( Usg=Specific Gravity)
Staff are then required to offer the identified player(s) the opportunity to drink more both prior to, and during the match
Other ways to evaluate Hydration Status
The simple way to assess hydration status is to look for the common signs of dehydration – increased thirst, dry mouth and concentrated or dark yellow urine. When a person is well-hydrated their urine is generally clear and light yellow in colour.
More sophisticated techniques that provide a numerical value include measurement of urine specific gravity, urine colour charts, and urine osmolality
Another reliable way of evaluating dehydration resulting from vigorous or prolonged exercise is by measuring change in body mass (refer below).
Body mass measures
All players record their BM approximately 15 min prior to and immediately following each match or session
Best to take BM with players in football clothing (and boots). To account for the trapped sweat, the mass of this attire should be measured pre- and post-match and then subtracted from the BM measures. No measures of fluid intake were taken.
The ∆BM during each match was calculated according to the following equation: ∆BM = (corrected BMpost – corrected BMpre)