Her dream is deeper, much more than thought. The heart just beats. His cold body seems to stop, like a half-death. The hibernation process seems a mystery of nature, but bears have been even more amazing than I could expect. Researchers at the Institute of Arctic Biology University of Alaska Fairbanks in the U.S. have discovered that American black bears show large decreases in metabolism during hibernation, levels of "break" in their bodies never before been detected . To make matters worse, this "quiet" is not biological suddenly interrupted when spring arrives, but the animal still "low bottom" for an extended period after leaving its burrow. The work, published in the journal Science, advances in the characteristics of a physical process that could be key in the treatment of cardiovascular disorders.
Oivind Toien explains, director of the study, "in general, an animal's metabolism slows down about half for every 10 degrees centigrade decrease in body temperature. However, metabolism black bears are slow to 75 percent, though his body temperature dropped only five to six degrees. " The amount of metabolic suppression was a surprise. Toien team was also surprised when the metabolism Bears remained suppressed for several weeks after the animals leave their dens.
This is the first study to continuously measuring metabolic rates and body temperatures when black bears hibernate during the winter and then return to their burrows in the spring. The researchers implanted in five black bears captured in central and interior Alaska radio transmitters to record body temperature, heart rate and muscle activity. The bears were kept in structures that mimic their lairs, far from human disturbance, and controlled by infrared cameras.
bears into hibernation only breathe once or twice a minute and your heart will slow down between breaths, sometimes beat every 20 seconds. "Each time the bear take in air in breathing, heart racing for a short period of time in a similar way as you would in summer during the break. When the bears expire, the heart slows down and will go from 30 to 60 seconds until the next breath, "said Toien.
Asleep in summer
The researchers hoped to discover that the metabolism of animals returned to normal levels immediately after the animals return to the activity and leave their dens in spring, as do small animals like hibernating Arctic ground squirrel. But it was not. Their metabolic rates were half of normal in vernano, although her body temperature will return to almost normal 37 degrees Celsius. Tarn bears two to three weeks to stabilize metabolic rates in summer. "Bears that can be found free in the woods in early spring may be in a transitional phase," adds Toien.
The interest in the physiology of animals hibernating black bears and beyond comparative biology, since the implementation of the mechanisms of metabolic suppression to people in emergencies could save lives. "Quickly reduce the metabolic demands of the victims of stroke, heart attack or trauma stabilize and protect them until you get more time to control the situation medically and extend the optimal treatment times," said Brian Barnes, an author's work .
