REHYDRATION AFTER EXERCISE WITH FRESH YOUNG COCONUT WATER, CARBOHYDRATE-ELECTROLYTE BEVERAGE AND WATER
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Date
2001-05
Authors
MOHAMED SAAT, ISMAIL
Journal Title
Journal ISSN
Volume Title
Publisher
Pusat Pengajian Sains Perubatan Universiti Sains Malaysia
Abstract
This is cross-over randomized study that assessed the effectiveness of fresh
young coconut water (CW), carbohydrate-electrolyte beverage (CEB) and plain water
(PW) for whole body rehydration and blood volume (BV) restoration during a 2 h
rehydration period following exercise-induced dehydration. Eight healthy male
volunteers between the ages of 20 to 30 years (22.4±3 years), with an average V02max
of 45.79±1.52 mL. kg.-1.min:1 exercised at 60°10 of V02max at an environmental
temperature of 31.1±0.03°C and relative humidity (rh) of 51.4±0.1 % for 90 minutes
until 2.78±0.06°10 (1.56±0.05 kg) of their body weight (BW) was lost. After exercise, the
subjects sat for 2 h in a thermoneutral environment (22.5±0.1°C; 67.0±1.0010 rh) and
drank a volume of either CW, CEB or PW representing 120°/0 of the fluid lost. Fluids
were consumed in three boluses, representing 50°10 (781±47 mL), 40°10 (625±33 mL)
and 30% (469±28 mL) of the fluid lost, at 0, 30 and 60 min respectively of the 2 h
rehydration period. Subjects remained fasted throughout the rehydration period. The
drinks given were randomized and the exercise-induced dehydration were done at
one-week intervals. The percent of body weight loss that was regained (used as index
of percent rehydration) during CW, PW, and CEB trials was 75±5°10, 73±5°10, and 80±4
% respectively, but was not statistically different between trials. At the end of all the
trials the subjects were somewhat hypohydrated (range 0.08-0.20 kg BW below
euhydrated BW; p> 0.05) after the 2 h rehydration period since additional water and
BW were lost as a result of urine formation, respiration, sweat and metabolism. The
rehydration index, which provided an indication of how much of what was ingested
actually was used for body weight restoration, was again not different statistically
x
between trials (1.56±O.14, 1.36±O.13 and 1.71±O.21 for CW, CEB and PW
respectively). Although BV restoration was better with CW, it was not statistically
different from CEB and PW. Cumulative urine output was similar in all trials: CW
(394±75 mL), PW (351±47 mL) and CEB (325±69 mL). There were no differences at
any time between the three trials in hemoglobin concentration, serum Na+ and cr,
serum osmolality, urine output and net fluid balance. Urine osmolality decreased after
1 h during the rehydration period and it was lowest in PW trial. Plasma glucose
concentrations were significantly higher when CW and CEB were ingested when
compared with PW ingestion during the rehydration period. In conclusion, ingestion of
fresh young coconut water, a natural refreshing beverage, could be used for whole
body rehydration after exercise.
Description
Keywords
Sports Science