Heart beating slow down, the body temperature drops and anything else in the Organism is on stand-by. During hibernation the body of an animal is switched to another state.
Small animals that hibernate have a longer lifespan than similar-sized rodents which do not hibernate.
The Telomere Length in young edible dormouse decreases dramatically in the summer during the active phase, while the only marginally changed in the winter during the hibernation period. However in adult rodents there was a low rate of decrease in Telomere Length in the Winter, while the Telomeres in the Summer time even gained length. Growth plays probably a big role an important role as it results in more cell divisions and higher rate of metabolism which both contribute to the drastic shortening of Telomeres. In the adults however, the activity of Telomerase appears to be predominant.
As more weight an edible dormouse loses during the Winter, as higher was the rate of Telomere shortening. The loss of weight is a measure for activity of the rodent: As more often it awakes from the deep sleep as higher has to be the metabolic rate and more body fat is exhausted. The Telomere shortening and therefore likely also the Aging process was much slower in the animals that had the deepest and undisturbed hibernation sleep as compared to the disturbed litter-mates.
Hibernation seems to be a special body state which functions in bad environmental conditions to preserve all resources and the keep the body fit for the next activity phase [http://www.wissenschaft.de/wissenschaft/news/316740.html; http://rsbl.royalsocietypublishing.org/content/9/2/20121095].