Fern Glen Essays
To Sleep, Perchance to Dream
by Judy Sullivan

To answer the question "Why hibernate?" isn't difficult. Poking your proboscis out of doors on any winter day and feeling your mucus membranes shrink in sheer horror should provide at least one reason. A simple survey of your stomach should provide another. There's not much that looks appetizing in a frozen landscape, while the dreaded deer decimate any herb or shrub that offers any gustatory possibilities. So why not fall into the arms of Morpheus and slumber until spring?

By now, we've recovered from the National Enquirer expose of the bear facts. They don't really hibernate. Neither do many of our summer garden friends, including chipmunks, opossum, squirrels and skunks. The "true" hibernators in our area include Punxsutawney Phil and his woodchuck siblings, as well as our resident insect annihilators, the little brown bats. Again, the difference between "true" or "deep" hibernation and "regular" hibernation, or winter torpor (which is what the rest really do), is a matter of metabolic rate and respiration, with both dropping dramatically for a period of days or weeks in "true" hibernators.

In the enviable position of actually needing to gain excess weight in order that they might survive the winter, hibernators spend the summer and fall gorging themselves. Mmmmmmmmmm. Oops. Sorry. I was envisioning pumpkin cheesecake.

As I was saying, those ripe for a long winter's nap spend the summer accumulating fat reserves. Shortening days, colder temperatures and a dearth of desserts trigger a blood chemical similar to morphine. (As my etymologically inclined spouse isn't here with me I'll remind myself that the word morphine, as I'm sure you already know, has its origins in the Greek "morph," meaning "form." Mythical Morpheus could assume any in the dreams of sleepers.) This chemical, given the imaginative handle of "Hibernation Inducement Trigger," (HIT for short) knocks 'em dead. Virtually.

Interestingly enough, this torpor-inducing substance holds great promise as a preservative for hearts, lungs and livers awaiting new bodies, significantly increasing the length of time that they can remain viable. Astrobiologists, having read several science fiction scripts in which Earthling colonists relocate to distant planets in a state of torpor, want to know how HIT might make long space flights bearable (no pun intended). Some fans of cryogenics would like to use it to wait out stock market fluctuations and currently incurable diseases. Parents are closely following this research in hopes of putting it to good use when their children turn 16 years of age.

Now that our subjects (but, hopefully, not you) are asleep, we can think about how they're going to wake up. We know that mammals rouse every so often during hibernation. Why bother? Can't they simply spend the winter in blissful oblivion?

The answer - R.E.M. Rapid Eye Movement. Torpor doesn't produce it. Sleep does. We know that it's an essential component of body, especially brain, repair, although no one is really sure why. Dreaming is commonly associated with REM, although not all animals that experience REM have been proven to dream. Nevertheless, we find the intriguing result to be that hibernating mammals must wake up in order to sleep. Once awakened, they descend again through sleep stages into hibernation. At least in artic ground squirrels, it's been shown that one hour of REM sleep stabilizes the brain for four hours.

The waking process itself is equally astonishing, especially since it happens with such relative frequency. Blood flow to the brain can be reduced by 90% in those hibernating artic ground squirrels. Reduced blood flow means reduced oxygen and sugars, the primary sources of energy. This explains why we become comatose in a stuffy room without chocolate.

Remember "brown fat" from last week? It's converted into quick heat that sends the Sand Man packing. This increases blood flow, which puts oxygen and sugar back in circulation. Literally. The problem is that while the brain gobbles up the oxygen and sugar, it throws off toxic waste in the form of "free radicals." (Don't worry. I'll spare you all of the tired political puns.) In people, free radicals are known carcinogens. So, here we have a great design in which a brain wakes itself up only to commit suicide. What a nightmare!

Who will save us from an unhappy end? The suspense is killing you, isn't it? Our superhero? Ascorbic acid - also known as vitamin C. The blood and brain of hibernators can contain four times the amount of vitamin C as is found in the human body and their spinal fluid twice the amount found in our own. As soon as the evil toxins are unleashed, arsenals of vitamin C are deployed to effectively neutralize the enemy.

Although humans, unlike hibernators, can't manufacture vitamin C in their livers, this particular phenomenon of the battle between brain cells and free radicals is proving to be a stroke of luck to those that research ischemia in people. It's speculated that the administration of vitamin C to victims of stroke may help prevent some of the cell death that occurs as the brain begins to resume blood flow. This same cooperation between wildlife biologist and human physician exists in the hopes of unraveling the molecular process that enables the brains of those same artic ground squirrels to reduce their need for oxygen during hibernation. (Useful little creatures, aren't they? The ground squirrels, that is.)

This has been a lot of information to digest. Why not take a page from nature? Kick off your shoes and settle in with a nice hot cup of Celestial Seasoning's Hibernation Inducement Trigger tea. I'll wake you in time for next week.

Questions, comments, or other feedback to Judy Sullivan.