As you become dehydrated, your bodys core temperature increases. This adversely effects your cardiovascular function and reduces the capacity for physical work.
Even a small decrease in your body's hydration level can decrease your performance. Studies have shown that even mild dehydration of 3% of body weight can decrease muscular strength by 10%.
When 4% - 5% or more of total weight is lost in water, muscular and aerobic endurance can decrease by 20% - 30%. If more than 10% - 12% of the body's weight as water is lost you could die.
How much water should you drink?
Themost common guideline for water intake is to drink eight to ten 8-oz glasses of water per day (64-80 oz per day). The 8 to 10 glasses guideline is okay as a ballpark, but takingtaking into account activity levels and caloric expenditure will give you an even more accurate and individualized estimate of your water needs.
Your level of thirst is not a good indicator of your level of hydration. By the time your body registers the sensationof thirst, you're already somewhat dehydrated. Therefore, you should continue to drink water throughout the day, even when you are not thirsty.
Another suggestion, is to err on the side of too much water rather than too little. You should make it a habit to drink water all day long, but because water is so important, you should make it a habit to drink heavily before, during and after your workout.
To Your Success,
Carlo Alvarez
Train Smart. Train Hard.