Note: caffeine and alcohol are dehydrating in the body, so try to avoid them. If you do drink them during this re-hydration program, you would need to drink an extra glass or two of water just to gain back what you will lose. 2. Drink enough water daily. In order to rehydrate a dehydrated body, you need to drink at least one-half ounce per pound of body weight daily. So, for example, if you weigh 180 pounds, you would drink 90 ounces (about 3 quarts) of water. During exercise or hot weather, you should increase your water intake significantly, depending on how much you sweat, how long you exercise, or how hot the temperature is.
How pressure decreases with altitude. As you go higher in the air, the atmospheric pressure decreases. The exact pressure at a particular altitude depends of weather conditions, but a couple of approximations and a formula can give you a general idea of how pressure decreases with altitude.
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. For example, there are fewer molecules above the 50 km surface than are found above the 12 km surface, which is why the pressure is less at 50 km. What this implies is that atmospheric pressure decreases with increasing height. Since most of the atmosphere's molecules are held close to the earth's surface by the force of gravity, air pressure decreases rapidly at first, then more slowly at higher levels.