Question: how long can a human suvive in the sahara without food and water

Emma Ross answered on 17 Jun 2013:

It’s dehydration-or the lack of water- which will be most dangerous. We can survive without food for a lot longer than we can without water. Because the Sahara is really hot, it makes the situation worse,because one of the ways we keep ourselves cool is to redirect a lot of our blood flow to the skin, so the blood, which carries our body heat, can be near to the cooler outside of the body. So we cool down by sending our blood to just below the skins surface, and the heat can dissipate into the cooler atmosphere around us.

It’s really important that we get rid of heat from our body when we are hot, because if we get too hot, the cells in our bodies stop functioning very well, and this can be very dangerous.

But, because blood is half water, if we become dehydrated then we reduce the amount of blood we have in our circulation, and this means there is less blood to take heat to the skins surface to cool us down, and so we overheat more easily. Not having water in a hot situation is even more dangerous that not having water in normal conditions.