Microbial Provision of Essential Amino Acids: Protein Conservation in Hibernation

Adaptations of sleep and cardiac rhythms in the hypometabolic state of a human-sized hibernator

PI: Øivind Tøien, PhD

Bear being imaged in the UAF HaMR Core MRI.

Regulation of the parasympathetic nervous system (PSNS) and sleep may play a role in the metabolic down-state of black bears, a human-sized hibernator. By activating the PSNS, bears lower their heart and respiration rates, blood pressure, and overall tissue oxygen demand to achieve a hibernation state. Being closer in size to humans and hibernating at a temperature compatible with human physiology, the bear model has potential biomedical applications for the treatment of cardiac arrest and stroke, offering a possible shorter path to clinical use to improve patient outcomes.

Dr. Tøien was recently awarded a NIH grant from the Office of Research Infrastructure Programs (award number 1R24OD035499-01). This funding will allow UAF to modernize summer housing for American black bears to support hibernation research using black bears as a biomedical research model. 

A black bear reduces its metabolic rate by 75% during hibernation, lowers its body temperature to 32°-34° C, and decreases its normal resting heart rate from 55 to 14 beats per minute. A hibernating bear takes about 1 breath/45 seconds compared to 15 to 20 breaths/minute for an active bear.

(All photos © Øivind Tøien)