We read of desert runners drinking ten litres of water in a twelve hour period. I did it once and the next day I was vomiting and feeling very poorly. If you suddenly start imbibing massive amounts of liquid you will feel disoriented and ill and not up for much exploring. Also, when you read of massive water intake it is during the summer. Which we never visit the Sahara during. In the winter you need much less water.
More importantly you must drink it at the optimum time for absorption. This is known intuitively by the Bedouin. They don’t sip sip sip all day long. They drink in the early morning and in the evening and that’s that. The rest of the time they down countless cups of tea. Tea is the secret rocket fuel of the desert. Made with lots of sugar it resets the body’s dehydration meter. In simple terms, if you drink unadulterated water it passes rapidly through the system. If you also drink tea the water you also drink gets processed into deep rehydration rather than for mere cooling activity. Sipping a bit as you walk is fine - but just to keep your mouth and lips from drying out. Swilling the water around before swallowing it works well. The water you drink you want to count. You don’t want it to be burnt off instantly as sweat. So you must remain cool, do not over exert yourself. Watch how the Bedouin cover up and avoid too much sun. I’ve never seen a desert dweller in shorts and a T-shirt. The only time a Bedouin would ever strip off is maybe when they’re digging out a well in summer.
In the winter we allow 3 litres a day for drinking in the first few days as you adjust to a dry atmosphere. The temperatures at night can be as low as 5 degrees C. During the day it may reach 25-27 degrees. Often there is a cooling breeze. As long as you not over exerting yourself you will not dehydrate. In fact I’ve seen people arrive who are already dehydrated (by lifestyle and alcohol intake) who actually rehydrate in the desert on 3 litres a day. This does not include cooking and tea for which we allow another 2 litres per person. The 8th Army, who fought in the Sahara throughout the summer during WW2 allowed 3 litres per man for cooking, drinking and tea. ...
Remember - if you’re sweating in the desert in winter you are doing something wrong. If you’re not sweating you don’t need much more water than you usually drink at home during a moderate summer.