Contrary to what is depicted in movies, this could be a forever unattainable obstacle for humanity.
In films, especially in science fiction, a common solution for time travel is simply putting astronauts into a “sleep.”
The reduction of astronauts’ metabolism could lead to unpredictable consequences.
In this hibernation-like state, metabolism drops to a minimum, and importantly, the astronauts’ minds are not burdened with boredom while waiting for weeks or even months.
In reality, the premise of putting astronauts into a state of “hibernation” seems well within reach, as even the European Space Agency is seriously considering the scientific aspects behind this concept.
However, a crucial point in a recent study by three researchers from Chile revealed a mathematical barrier to making human “hibernation” a reality, by clarifying the relationship between body mass and energy expenditure in mammals during hibernation. This obstacle may render the idea forever beyond our grasp.
Specifically, the researchers found that the minimum metabolic rate necessary for cells to survive in low-temperature, low-oxygen conditions is insufficient. In other words, for relatively heavy animals like us, the potential energy savings we could expect when entering a state of hibernation or deep sleep would not be significant.
Moreover, the detrimental effects of reducing astronauts’ metabolism could lead to unpredictable consequences. In some small animal species, even in hibernation, they can lose over a quarter of their body weight due to burning stored energy. For humans, this number could be even higher.
From this reality, Roberto F. Nespolo – the lead author of the study, suggests that we are better off sleeping in a conventional way.
Bears can hibernate, but this is a feat that very few mammal species can achieve.
The concept of hibernation often evokes the image of a bear locking itself in a cave to sleep, waiting for time to pass after a long winter. However, in reality, despite bears almost ceasing activity for several months, their level of hibernation is still not as effective as that of smaller creatures like ground squirrels or bats.
In these animals, their body temperature drops significantly, metabolism is nearly zero, and heart and breathing rates slow down. This process can reduce energy consumption by up to 98% in some cases, thereby eliminating the need to hunt or forage.
However, as mentioned earlier, this is a different story for mammals. The researchers argue that the expanded relationship between active metabolism and body mass has led to the conclusion that hibernation does not actually save much energy for larger animals, but rather has many negative impacts.
Bears are one of the rare mammal species that can hibernate effectively. When they sleep, a bear’s breathing rate is about 50 breaths per minute. During the coldest part of winter, the breathing rate drops dramatically to only 4-5 times per minute. All bodily functions of the bear come to a halt, yet when spring arrives, they wake up and their body remains intact. Scientists believe that if humans were to sleep under similar conditions, we would quickly lose both bone and muscle mass.
Before bears hibernate, they also accomplish another biological feat, which is that they need to gain weight to an extremely dangerous extent. For humans, reaching such a level of obesity would cause irreparable harm to the body.
Additionally, during hibernation, the cooling of the body, reduction of heart and breathing rates, and forced reduction of metabolism may not yield the results we expect.
