The Tøien research project was completed with COBRE funding in August 2024 and continues with new support from Alaska INBRE, funded by an Institutional Development Award (IDeA) from the National Institutes of Health, P20GM103395.
Øivind Tøien, PhD, Research Associate Professor, IAB UAF
Tøien’s research analyzes more than 3,500 days of unpublished polysomnographic recordings from long-term hibernation studies in American black bears tracking rates for heart, respiration, and blood pressure. This data aims to enhance understanding of how sleep and parasympathetic autonomic control may influence and support the metabolic down-state of black bears, which are human-sized hibernators. During hibernation, a black bear decreases its metabolic rate by 75% with only a moderate 5.5 °C decrease in body temperature. While bears do not rely on dramatic drops in body temperature to sustain suppression of their metabolic rates during hibernation as deeper hibernators, such as the Arctic ground squirrels do, they can reduce their heart rates from a normal resting level of 55 beats per minute down to 14 beats per minute during mid-hibernation. This process is modulated by extreme cardiac sinus arrhythmia that occurs without adverse effects on the heart. Bears, unlike typical hibernators, possess the ability to maintain environmental awareness during hibernation and can respond if disturbed. This study aims to provide critical information that will advance the understanding of mechanisms by which a hypometabolic state in a human-sized hibernator can be induced which may lead to the development of new treatment strategies for patients suffering from stroke,
cardiac arrest, and trauma or are undergoing critical medical procedures.
