In contrast to most mammals, hibernating bears demonstrate limited loss of muscle mass and protein content over the prolonged periods of immobility and fasting during winter These changes likely contribute to maintenance of muscle protein content and preservation of muscle mass during prolonged inactivity, fasting, and metabolic suppression in hibernating bears. This suggests that bears have natural adaptive mechanisms preserving muscle mass and functionality.
Physical inactivity generates muscle atrophy in most mammalian species In this study, we examined the alterations in the regulatory systems of protein and energy metabolism in the skeletal muscles of asiatic black bears during hibernation. In contrast, hibernating mammals demonstrate limited muscle loss over the prolonged intervals of immobility during winter, which suggests that they have adaptive mechanisms to reduce disuse muscle atrophy.
The maintenance of protein biosynthesis and decrease in protein catabolism through the mtorc1 signaling as response to bcaa availability likely contribute to the preservation of muscle protein through prolonged periods of immobility and fasting during hibernation.
