|
IMMEDIATE RE-HYDRATION POST-EXERCISE IS NOT COINCIDENT WITH RAISED
MEAN ARTERIAL PRESSURE OVER A 30-MINUTE OBSERVATION PERIOD
|
Bartholomew
Kay1
, Brendan J. O'Brien2 and Nicholas D. Gill3 |
1Massey University, Institute of Food, Nutrition, and Human Health,
Palmerston North, New Zealand
2University of Ballarat, School of Human Movement and Sport Sciences,
Ballarat, Australia
3Waikato Institute of Technology, School of Sport and Exercise
Science, Hamilton, New Zealand
| Received |
|
02 May 2005 |
| Accepted |
|
29
August 2005 |
| Published |
|
01
December 2005 |
©
Journal of Sports Science and Medicine (2005) 4, 422
- 429
Search
Google Scholar for Citing Articles
| ABSTRACT |
| This
investigation assessed the effects of immediate or delayed re-hydration
post-exercise, on mean arterial blood pressure (MAP) and on blood
plasma volume (PV) expansion post-exercise. It was hypothesised that
fluid ingestion would raise MAP and attenuate PV expansion. On two
occasions separated by seven days, eight males (age 20.4 ± 1.7 years,
mass 79 ± 5 kg [means ± SD]; VO2max 48 ± 11 mL·kg-1·minute-1,
[mean ± SE]) cycled in the heat (35oC, 50% relative humidity)
at a power output associated with 50% VO2max, until 1.0kg
body mass was lost. 1L water was given either immediately thereafter,
or two hours post-exercise by random assignment. On both occasions,
MAP was calculated every five minutes for a period of 30-minutes post-exercise,
and change in PV was calculated 24-hours post-exercise. Repeated measures
ANOVA for MAP results suggested a low probability of a treatment effect
(p = 0.655), a high probability of a time effect (p = 0.006), and
a moderately high probability of a time x treatment interaction (p
= 0.076); MAP tended to be lower when fluid had been consumed. PV
expansions 24-hours post-exercise were not significant changes with
respect to zero, and were not significantly different by treatment
condition. In conclusion: (a) The exercise was not sufficient to elicit
significant PV expansions; thus, we were unable to determine the effects
of the timing of post-exercise re-hydration on PV expansion. (b) The
hypothesis regarding MAP in response to drinking was not supported,
rather there was a 92% probability that the inverse affect occurs.
KEY
WORDS: Dehydration, re-hydration, blood pressure, plasma volume.
|
|
|
