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EFFECTS OF PALM VITAMIN E SUPPLEMENTATION ON EXERCISE-INDUCED OXIDATIVE
STRESS AND ENDURANCE PERFORMANCE IN THE HEAT
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Chen
Chee Keong1 ,
Harbindar Jeet Singh2 and Rabindarjeet Singh1 |
1Sports Science Unit and 2Department of Physiology, School of
Medical Sciences, Health Campus, Universiti Sains Malaysia, 16150 Kubang
Kerian, Kelantan, Malaysia.
| Received |
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11 March 2006 |
| Accepted |
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03
October 2006 |
| Published |
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15
December 2006 |
©
Journal of Sports Science and Medicine (2006) 5, 629 - 639
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| ABSTRACT |
| This
study investigates the effects of tocotrienol-rich palm vitamin E
supplementation on exercise-induced lipid peroxidation and endurance
performance in the heat. In a double blind, cross-over study, eighteen
healthy, male recreational athletes completed two endurance running
trials, until exhaustion, on a motorized treadmill at 70% VO2max
on two separate occasions following a 6-week supplementation regimen
of either tocotrienol-rich palm vitamin E (E) or placebo (P). Both
trials were conducted in the heat (31oC, 70% relative humidity). During
the trials, rectal temperature (Trec), ratings of perceived exertion
(RPE) and oxygen uptake (VO2) were recorded. Blood samples
were collected for the determination of plasma volume changes (PVC),
malondialdehyde (MDA), creatine kinase (CK), total antioxidant status
(TAS) and vitamin E. After the supplementation regimen, serum alpha-tocopherol
increased ~33% but serum concentrations of tocotrienols were negligible.
No significant differences were evident in mean Trec, RPE, VO2
or in the time to exhaustion between the E-supplemented and the placebo-
supplemented groups. Similarly, mean PVC, CK and TAS were also not
different between the two groups. Resting plasma mean MDA concentration
in the E-supplemented group was significantly lower than that in the
placebo-supplemented group. At exhaustion, plasma mean MDA was higher
than the resting values in both groups. Although tocotrienol-rich
palm vitamin E supplementation decreased lipid peroxidation at rest
and, to some extent, during exercise in the heat, as evident from
the lower MDA levels, it however did not enhance endurance running
performance or prevent exercise-induced muscle damage or influenced
body core temperature or plasma volume changes during exercise in
the heat.
KEY
WORDS: Oxidative stress, endurance, heat, malondialdehyde, palm
vitamin E.
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