Just using a LOT of water is a bad idea (unless you eat a good amount, with salt and other nutrients around that time). Because as we all know, this can lead to hyponatremia (at the risk of stating the obvious: you sweat out a lot of salt with the water you lose. Only replacing the water dilutes your blood (serum).
As altitude  increases, the air becomes less dense because of the smaller amount  of air above that altitude. There is a corresponding decrease in  pressure with an increase in altitude. Eventually you reach a point  without air, and the pressure decreases to zero. That is space. + 91 others found this useful.
Since more than half of the atmosphere's molecules are located below an altitude of 5.5 km, atmospheric pressure decreases roughly 50% (to around 500 mb) within the lowest 5.5 km.Above 5.5 km, the pressure continues to decrease but at an increasingly slower rate. Terms for using data resources.CD-ROM available.ressure with Height pressure decreases with increasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.