Why is it impossible for humans to hibernate during space travel?

Contrary to what is seen in the movies, this could be an obstacle forever beyond humanity's reach.

In movies, or science fiction, it is easy to see that an important solution to time travel is to simply put the astronauts to "sleep".

Lowering the metabolism of astronauts can lead to unpredictable consequences.

In this hibernation-like sleep state, metabolism is reduced to a minimum, and it is important that the astronauts' minds are no longer bored with waiting for weeks, or even even for months.

In fact, the premise of putting astronauts into "hibernation" feels like a complete grasp, so that even the European Space Agency is seriously considering the science behind it. after this concept.

However, the heart of a recent study by 3 researchers from Chile, revealed a mathematical barrier in making human "hibernation" a reality, through unraveling Relationship between body mass and energy expenditure in hibernating mammals. This impediment even keeps the idea forever out of our reach.

Specifically, the researchers found that the minimum metabolic rate that allows cells to survive in conditions of low temperature and low oxygen is not enough to guarantee. In other words, for relatively heavy animals like us, the potential energy savings we might expect when entering hibernation, or deep sleep, won't really be significant.

That is not to mention the harmful effects of reducing the metabolism of astronauts, which can lead to unpredictable consequences. In some small animals, even in hibernation, they can still lose more than a quarter of their body weight by burning off stored energy. For humans, this number is even larger.

From this fact, Roberto F. Nesporo - the lead author of the study, suggests that we are better off sleeping in the usual way.

Bears can hibernate, but this is a feat that very few mammals can do.

The concept of hibernation often conjures up images of a bear locking itself in a den to sleep, waiting for time to pass after a long winter. However, despite the fact that bears are mostly inactive for several long months, their hibernation is still not as effective as the true hibernation of smaller creatures such as ground squirrels or bats.

In these animals, their body temperature drops sharply, metabolism is almost zero, heart rate and breathing rate both slow down. This process can reduce energy consumption by up to 98% in some cases, thereby eliminating the need to hunt or forage.

As stated above, however, it's a different story for mammals. The researchers suggest that expanding the relationship between active metabolism and mass produced has come to the point where hibernation doesn't really save much energy for larger animals, which has many negative effects.

Bears are rare mammals that can hibernate at an efficient rate. When they sleep, the bear's breathing rate falls to about 50 beats per minute. In the coldest part of winter, the breathing rate drops to a very deep level, only 4-5 times / minute. The bear's whole body activity stops, but when spring comes, they wake up and their bodies are still intact. Scientists think that if humans slept in the same conditions, we would lose both bone and muscle very quickly.

Before the bears go into hibernation, they have accomplished another biological feat, which is that they need to gain dangerously high fat. For humans, if fat is that much, the body will be irreparably damaged.

In addition, during hibernation, cooling the body, reducing heart rate and breathing rate as well as forcing a decrease in metabolism may also not bring about the results we expect.