Phun Physiology: Celebrating the Winter Solstice, or Biking to Beat the Blues

As you can see, a winter sun has its moments.

But there are always two sides to every story. . .

A winter sun is lazy; and if you’re not careful, it will try to drag you down, too.

Sol is a real slacker this time of year. He’s developed a bad habit of rising late, retiring early, and barely getting off the ground. His uninspired arc—47 degrees lower than his summer high—invites derision, even from those not normally given to name-calling.

Indeed, solar scholars have a fancy and very unflattering word for Sol’s wintry disposition: “solstitium,” which means “sun standing still.”

Think about it. How would it make you feel if a bunch of cyclists were to call you “velostitium” as they overtake you from behind?


The winter solstitium is a three-day period when the sun’s daily high is at its yearly low. The middle day of the three marks the official Winter Solstice, the shortest and darkest day of the year—December 21st, this year.

I pay attention to the date. Not because I’m given to mysticism, or because it marks the official beginning of winter. On long rides, I usually run out of daylight, playing right into the Dark Monster’s hand.

Sure the Solstice affects me in other ways, too. A little weight gain, a tendency to back off a bit on training, a tendency to eat a little more this time of year . . .

I really can’t complain though, since some have it much worse. In fact, there’s a term for those who suffer depression due to the shortened daylight hours of winter. It’s called seasonal affective disorder, whose acronym (SAD) actually makes sense.

This article isn’t directly about SAD, though. I don’t make diagnoses or give medical advice. Rather, it’s about a much milder and more common non-medical situation often referred to as “cabin fever,” “winter blahs,” and “winter blues.” It just so happens that the literature regarding the treatment of SAD is useful here.


There are a couple of tricks that cyclists can pull from their long-sleeve wool cycling jerseys that may help them beat the winter blues!

Winter training is important, since that January brevet is just around the corner. But training isn’t just about brawn. It’s also about brain, or, brain chemistry. The combination of a little sunlight and exercise fine tunes the release of a handful of brain chemicals that make us feel, well, like summer. The secret ingredients of this special concoction, which I’ve somehow managed to write down, include melatonin, serotonin, norepinephrine, dopamine, and endorphins.

The first ingredient on the list, melatonin, is a hormone produced by the pineal gland. The remaining substances listed are neurotransmitters—special chemicals manufactured by brain cells for communicating with one another. The levels of these neurotransmitters often drop in winter. The trick, then, is maintaining their levels, if possible.

I’ll explain how cyclists might accomplish this, if readers can bear with me for a minute.


Did you ever wonder why bears go on an eating binge, gain weight, and then hibernate until spring? Because they can?

According to biologists, melatonin is the answer. Bears hibernate because they produce more melatonin as a result of decreased daylight with the onset of fall. Melatonin alters circadian rhythms, or sleep cycles. It happens to humans as well. Altered sleep cycles leave many people feeling less energetic. However, a few are greatly affected to the point of depression. Experts estimate that as much as 10% of the US population suffers from winter depression, or SAD.

The melatonin theory for SAD is bolstered by the fact that many of its sufferers respond positively to light therapy. Sunlight resets circadian clocks and the timing of melatonin release, getting sleep cycles back on track, and reestablishing energy levels. Of great interest is the fact that sunlight can also be an effective antidote for those with a simple case of winter blahs.

There’s more good news. Both sunlight and exercise boost the production of a couple of anti-depressant neurotransmitters, which are commonly in short supply during winter and hypothesized to be linked with SAD: dopamine and serotonin. Additionally, exercise may also boost levels of another, antidepressant neurotransmitter, norepinephrine.

Indirect evidence that low levels of serotonin, dopamine, and norepinephrine play a role in SAD comes from the pharmaceutical industry. There are a number of commercial antidepressants whose success is based on the fact that they increase the levels of each of the three aforementioned neurotransmitters.

Lastly, endorphins are central nervous system neurotransmitters, which are produced as a direct result of exercise. Called “natural painkillers,” they cause the euphoric “runner’s high.” As natural opiates, their effects not only mimic morphine and heroine, they are more powerful. Their effects however are short lived.

In summary, a great percentage of the population could possibly benefit from a combination of sunlight and exercise this time of year. Spinning on a stationary bike would be a step, err, rotation in the right direction. Even better if it were located by a large window with a southern exposure. Best of all, would be to get outdoors on a sunny day for a spin.

Let the pieces come together. Celebrate the Winter Solstice!