Many people have seen him drinking his own urine in the acute water crisis on Bear Grylls' Man Versus Wild. But in reality in any survival situation drinking one's own urine may be the biggest mistake. Because,
First, a person is dehydrated due to thirst for water. Then if you drink urine, your body will become more dehydrated because urine contains high levels of sodium salt like sea water. In addition, urine contains a variety of bacteria that can cause gastrointestinal problems and infections.
Second, urine contains formaldehyde, ammonia and solids in dissolved state. Drinking urine will re-enter the body with these harmful substances, which will put pressure on the kidneys. In a dehydrated state, the kidneys may not be able to properly purify these contaminants. This can lead to permanent kidney damage.
Again, many say that urine is sterile so it is safe to drink. But according to modern research, urine is not sterile. Drinking urine in a dehydrated state can cause vomiting and even diarrhea. So you cannot drink urine directly. Urine can be purified and drunk for survival.
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