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The effects of low-fat skim chocolate milk on urinary hydration indices in a sample of Division 1-AA cross country runners during off-season training sessions
Journal of the International Society of Sports Nutrition
Poster presentation The effects of low-fat skim chocolate milk on urinary hydration indices in a sample of Division 1-AA cross country runners during off-season training sessions
Jamie Ghigiarelli 0
Katie Sell 0
Michelle Blum 0
Nicholas Dagastino 0
Peter Alfano 0
0 Address: Department of Physical Education and Sports Sciences, Human Performance Lab, Hofstra University , Hempstead, NY 11549 , USA
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Background
A randomized cross over design study was performed to
examine the effects of three different hydration drinks
(water, W; gatorade, CHO-E; and low-fat skim chocolate
milk, CHC) post exercise in a sample of Division 1-AA
cross country runners during off season practice sessions.
Methods
Urine samples were collected from nine cross country
runners twice a week (on the intense interval training days
each week) for six weeks pre and post practice sessions.
Each week participants consumed one of the three
rehydration drinks. Participants served as their own control
and drink choice was randomized in a cross over design
across the three drinks. Urine was tested at four different
times on each of the experimental days; (1) before
practice (PRE), (2) immediately after practice (IPE), (3) 60
minutes after practice (RECV), (4) and a midnight sample
(PST). Four urine indexes were examined on each of the
experimental days to assess the difference in hydration
status using the three experimental drinks: 1) Urine
osmolality1 (Uosm), 2) specific gravity2 (Usg), 3) volume of
urine output3 (Uo), and 4) urine color4 (Ucol).
Results
Rehydration of low-fat skim chocolate milk post exercise
exhibited a non-significant decrease (p = .08) of
approximately 35% in urine volume output throughout the
evening in the CHC group (346 ± 95 ml) when compared
to CHO-E (476 ± 188 ml) and W (549 ± 240 ml) groups.
Urine osmolality, specific gravity, and color scores
gradually decreased across all drinks from 60 minute recovery to
nightly urine samples with a more significant drop
observed in the control (W) group (p = .03osmo, .01color)
This indicates rehydration occurred after exercise using all
the drinks however, it appears a slower rate of hydration
occurred in the chocolate milk and CHO-E groups. A
secondary finding was a significant correlation did exist
between urine osmolality and urine specific gravity (r =
0.83*), while weak non-significant correlations occurred
between urine osmolality and color (r = .557) as well as
urine specific gravity and color (r = .367).
Conclusion
The results of this study suggest that implementation of a
nutrient dense drink (chocolate milk) post exercise will
show a non-significant trend to reduce urine output. Due
to its high macronutrient and electrolyte content
chocolate milk may be a viable way to reduce urine output and
increase water retention which may allow one to maintain
a more euhydrated state post exercise. It is also concluded
the indices of urine osmolality and urine specific gravity
indicate a strong relationship as markers of hydration
status as opposed to urine color. This information could be
Acknowledgements
The authors would like to thank the American Dairy Association and Dairy
Council, Inc (ADADC) for the grant funding of this research project. In
addition, we would also like to thank Matt Pikosky, Director of Research
Transfer of Dairy Management Inc (Rosemont, IL) for his assistance in the
experimental design of the manuscript. (...truncated)