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2.5. Effects of Dehydration on Physical Performances and Health
About 12-15 of the population has kidneys stones with several inducing factors such as the drinking water habitual. The prevalence of kidneys stones resemble in the
population which has low urine excretion so there are elevating concentrations that ease the formation of the stone. The risk will increase if the urine volume less that 1 liter per
day. If the drinking behavior is increased until the urine excretion reaches 2-2.5 liters per day the formation of the kidney stones can be prevent even without the support of diet
changing behavior and other medication. Several studies show that there are a correlation between water consumption and
the trend of cancer bile, prostate, kidney, testicle, urethra, large intestines, and breast. Study in Seattle shown that women who drank more than 5 glass of water per day, had a
decreased risk of having large intestines cancer of 45 compare to the ones who drank less than 2 glass of water per day.
It has been proven that in child and adult population, there is a correlation between the consumption of water with obesity reduction because consuming a lot of water can
reduce hunger sensation. Besides that, mild dehydration in adult can cause salivary gland disorientation. Acute diarrhea can trigger mild to medium dehydration which is shown by
dry mucous membrane of the mouth, dry skin, thirst, dizziness, and sunken eyes. Kleiner 1999 review the correlation of dehydration with health status usually in kidney stones
patients. Study review show that dehydration 1 of body weight loss decreased physical
and physiological performance that related to the sports ability. The reduction through 2.2 can lower the pulse rate and the increasing the incidence of stroke during light and
excessive sports. The effects of dehydration towards physical performance are being studied through
two different sides of view which is voluntary and involuntary Williams 2005. Voluntary dehydration often happen in athletes through perspiration by sports, the use of sauna,
diuretics, or consuming less food or beverage. Involuntary dehydration usually happens through excessive perspiration during sports in a high temperature environment.
Commonly explained that dehydration can cause dehydration which affect several physiologic metabolism and finally decreasing physical performances. Sawka
et al. 2000 reports that dehydration can decrease the intracellular and extra cellular liquid and also
cardiac output. Body temperature will increase because the decreasing process of perspiration. Dehydration is also impaired the balance of electrolyte in the muscle.
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Studies on the effect of voluntary dehydration toward physical performances still inconsistence and needs further study Williams 2005. It is explained that dehydration of
4-8 body weights did not interrupt the physical performances such as intense muscular effort, isomeric muscle strength or endurance. In the other side, it is reported that 4
dehydration has a significant effect towards anaerobic muscular endurance slower to 20- 30 seconds and decreasing 15 knee extension endurance. The dysfunction mechanism
analysis was related to the lost of cilium and the increasing of muscle temperature during sports. It is being stated that no study has shown that dehydration could increase
physical performance. Study on involuntary dehydration show that dehydration less than 2 of body
weight has disturbed physical performances Williams 2005. It is reported that it was related to the cardiovascular function and body temperature adjustment. Dehydration
significantly decrease 4-8 maximal aerobic ability when the total body weight decrease into 3 in the athletes that doing sport in normal temperatures area and the disturbance
getting severe in a high temperatures area. Dehydration also decreases plasma volume which affects the cardiac output and the stream flow of blood through skin and muscles.
The reduction of blood flow through the skin is shown by the decreasing of perspiration and elevation of body temperature. The increasing status of dehydration will increase
body temperature and heart beat and even decrease the amount of the blood that pumped by the heart per beat stroke volume.
2.6 Effects of Dehydration on Mental and Cognitive Performance
The study of Gopinathan et al reflects the effect of dehydration caused by affected
by the differences of weather towards mental performances. Two percents of liquid deficiency can decrease the arithmetic ability, short terms memory and visual focus.
The research about dehydration effects on memories is relatively new Grandjean Grandjean, 2007. The study of Gopinathan
et al. 1988 and Cian et al. 2001 indicate that dehydration which contribute to more than 2 of body weight loss could reduce
cognitive performance. The dehydration occurs because of less water consumption, excessive physical activity, or having high temperature sports. Gopinathan
et al. 1988 study involved 11 healthy adult which having different level of dehydration resulted by the
treatment combination using water intake restriction and high temperature sport activity showed the positive correlation between cognitive disorientation and the severe status of
