A famous American baseball star died in 2002. His body was quickly frozen in liquid nitrogen at MINUS 196 degrees Celsius. It is expected that in a few years, mankind will have mature technology to thaw it and bring it back to life. This seemingly naive idea is faced with a difficult problem in reality-when the human body is frozen, the water in the blood will freeze, and tiny ice crystals will destroy capillaries and cells. This thorny problem has not been solved by human beings.
But there are creatures in nature who can handle this problem perfectly. Scientists have found that Alaskan forest frogs can freeze themselves into an ice block when they hibernate, but they will be alive and kicking after melting in spring. Why are they not destroyed by ice crystals in the blood?
It turns out that when the wood frog feels that it is going to freeze around, it will expel water from the body, and the liver will release a lot of glucose into the blood, which will increase its blood sugar concentration by hundreds of times! At this time, high concentration of blood sugar becomes a natural antifreeze. The vital organs of Rana chensinensis in China have been completely dehydrated and withered. You know, ordinary water freezes at zero, and salt-rich seawater freezes at MINUS 6.7 degrees. Sugar, like salt, can prevent liquid from freezing to some extent.
Scientists discovered "fairy wood" pollen in Sweden 12000 years ago. Because this plant lives in such a cold and hungry area as the Arctic, scientists speculate that the temperature in northern Europe such as Sweden was extremely low before 12000. Moreover, this temperature change process is very rapid, only around 1000 years, which is a very short moment in the long history. In other words, it is difficult for human beings to adapt to this sudden drop in temperature.
Sure enough, scientists found that thousands of people who were still hunting and gathering died of the cold, but a few people survived. We cannot help asking, how did they survive? Scientists firmly believe that human beings, like the Alaskan forest frog, have mobilized the biological instinct of the human body, and they "chose" the way to raise blood sugar to fight against freezing.
In cold conditions, such as cold water bath, people will feel "want to urinate". In other words, low temperature will stimulate people to urinate, or that urination is a self-defense measure to deal with low temperature. For a long time, scientists did not know the cause of this stress reaction. From the perspective of blood sugar and antifreeze: the human body will urinate, thus raising blood sugar and reducing the risk of frostbite.
In cold Europe more than 10,000 years ago, a small group of people had a certain gene. In the face of years of cold, their insulin supply became slow and their blood sugar increased. Moreover, they will urinate more frequently, reduce water in the body, and increase blood sugar concentration in disguise. Like the Alaskan forest frog, this small group of people lowers the freezing point of blood by raising the blood sugar concentration, thus reducing the risk of frostbite. They are more likely to survive in a cold environment.
You may have thought, are these not symptoms of diabetes? Yes, it may be that the gene of regular diabetes allowed our ancestors to survive the sudden drop of temperature in 10 thousand years. Of course, these genes will also be passed on to us. A study on diabetic patients further verified this conjecture. The researchers tracked and measured the relationship between blood sugar and body temperature in diabetic patients. The blood sugar level of diabetic patients is the highest in winter and the lowest in summer.
Therefore, the diabetes gene helps helpless ancestors to survive the severe winter to some extent, and wait until the climate gets warmer again. Of course, this function of regulating one's blood sugar due to external temperature is useless in modern society. Unless you live in extreme cold for weeks on end.