Bear in hibernation. Illustration by Angela Rizza

Laura Dean Bennett
Staff Writer

“Perhaps I am a bear, or some hibernating animal, underneath, for the instinct to be half asleep all winter is so strong in me.”~ Anne Morrow Lindberg

During what I called the “polar vortex of January 2018,” I found myself envying the animals who dig into dens and snooze through winter.

The temperature was 15 below zero and the wind was whistling a threatening tune – for days and days with no relief in sight.

I just wanted to crawl under the covers, turn the mattress pad heater up to “scorch” and read.

But Mother Nature had other plans for me. She blew winter into invisible cracks and crevices under the roof and into my house. 

She froze pipes, caused floods and played havoc with my cozy den, my peace of mind, my free time and my budget.

I felt more than justified in throwing my New Year’s resolutions out the door ­– you know, the usual – eat better and get more exercise. 

They didn’t even last a week.

Let’s just say, if New Year’s resolutions were chickens, they definitely flew the coop.

Instead of my usual over-indulgence with comfort food, I’m pretty sure I now have a full-fledged, anxiety-based eating disorder which might actually kill me.

For my own physical and mental health, I really should be hibernating in a hole in the ground.

Maybe what I’ve got is what doctors call seasonal affective disorder (SAD).

And maybe that’s the reason I’m jealous of animals who hibernate. 

Or maybe I’m not the only one, and the siren song of hibernation comes naturally to all of us.

The theory that seasonal depression is a distant relation of hibernation was dismissed by most scientists until the last several years when professionals began thinking that there might be something to it.

Seasonal affective disorder is different from other forms of depression. 

Studies have shown that clinically depressed people usually lose interest in food, finding it tasteless or even distasteful.

Many lose weight and have trouble sleeping. 

But those who have SAD are just the opposite – they eat and sleep a lot. 

Although SAD affects just a tiny percentage of the population, many researchers believe that most people who live in northern climes are affected to varying degrees by the winter blues. And that we may be experiencing a form of hibernation of sorts.

Like hibernating animals who sleep away the coldest months in their dens with lowered rates of metabolism, we also experience a physical slow-down. 

We want to overeat and oversleep, have much less energy, and some people report a drop in their romantic urges.

Theories vary as to why this happens.

Many researchers are studying SAD-related changes in the autonomic nervous system. 

Our autonomic nervous system regulates functions such as breathing and heart rate – the same non-voluntary bodily functions which affect, and are affected by, hibernation. 

Studies are indicating that these same genes could also cause seasonal depression.

There are two parts to the autonomic nervous system which work in opposition to control bodily functions. 

The sympathetic system boosts metabolism, while the parasympathetic system tamps down bodily functions.

As animals get ready to hibernate, they experience a spike in parasympathetic nervous system activity.

This causes their heart rate to slow down and decreases body temperature and metabolic rate. 

Recent research shows a similar parasympathetic response in humans who experience SAD.

While animals prepare for winter by fattening up and then sleeping though it, that’s not practical for humans, so we have adapted in different ways.

Some scientists theorize that our parasympathetic response causes us to deal with winter by eating more and thus, gaining weight through the winter, which in turn, causes a lack of energy and a desire for more sleep.

A study in Russia found that hibernation-like activity in people with severe cases of SAD (binge eating and excessive sleeping) indicated this to be an adaptive mechanism aimed at conserving energy.

A dwindling interest in romance is possibly another naturally intuitive adaptation to winter, according to Thomas Wehr of the National Institute of Mental Health.

Matthew Andrews, at the University of Minnesota, discovered that animals carry genes which automatically kick-start hibernation by changing the way their bodies convert fat reserves.

Similar genes have also been found in humans.

While Andrews says that the existence of these genes isn’t proof that humans did once hibernate, he does say, “If there were any vestige of hibernation in humans, it makes sense that it would be something like SAD.

“I suspect what we call winter depression has its origins in evolutionary biology,” he adds.

Some researchers say that SAD is a natural response to the shorter daylight hours of winter. 

Day length is a key factor for hibernating animals. 

The shortening period of light tells animals’ internal clocks that winter is approaching just as it triggers SAD in humans.

Treatment of SAD usually involves daily sessions basking in a strong light source that mimics sunlight.

This phototherapy works by tricking the circadian timekeeper in our brains, improving our mood and reducing lethargy.

Scientists believe that all humans have the potential to succumb to seasonal alterations, but most of us can pretty much ignore changes in day length because we live in a world of artificial lights.

Common sense would lead me to believe that people’s response to seasonal changes may have been more pronounced before electric lighting was common. 

If we struggle with winter depression, just imagine how bad it was when all people had to cheer them were candles, lanterns and fireplaces – and there really were wolves howling outside in the storm.

Luckily, we’ve got electricity, and we can brighten up our homes and our lives in a myriad of ways.

Or, we can crawl under the covers and grab the remote control. 

Of course, if things get really bad – well, desperate times do require desperate measures.

Many moredays of 15 below and I may have to find a comfy hole in the ground big enough to serve as my hibernation den. 

All I’ll need to survive is a bed, an electric blanket, a space heater, a small refrigerator, a hot plate and a microwave, a TV, my iPad, a huge pile of books, and my trusty sidekicks – my dog and cat.

Oh, and a bunch of really long extension cords.

It’s going to have to be a really big den.