The shortest days of the year are upon us. Are you finding it tough to have the motivation to get outdoors and actually do something like exercise?

The die-hard snowmobilers, skiers and hockey enthusiasts are out. But what about the rest of us? It turns out we may have a good excuse. Cold and dark actually have physiological effects on our bodies that are tough to overcome.

All animals deal with the cold in different ways. Many birds migrate to warmer climes. A number of Alaskans head for Hawaii. Birds store fat. So do Alaskans.

The bar-tailed godwit shrinks its internal organs we should be so lucky to have that ability; it would save trying to shed those Christmas pounds. Wood frogs convert glycogen stored in their liver to glucose which lowers the freezing point of liquids in their bodies, thus preventing ice crystals that cause cells to rupture. They also bury themselves in the mud, which would play havoc with those people who work for a living.

All animals store some body fat for the winter months. However, it isnt just the cold that affects us. Theres also the radically changing daylight. Consider that the mid-December day is a brief five hours compared to the summer days that are nearly 24 hours long.

All organisms respond to and anticipate that change. Our circadian rhythm allows us and other animals to know the time of day no matter whether light or dark. Humans, with our light bulbs and ticking clocks, are a little more out of tune than most animals, but we still have the ability in our systems. Our circadian rhythm regulates our body temperature and our wake-sleep cycles.

Circadian rhythm also is responsible for our physiological, emotional and behavioral functions.

During summer months, you might take a walk after work or run to the lake to fish for an hour before bed. Mid-December? That rarely happens. More than likely it is home to the couch, a beer and whats on TV.

This is not about being lazy. It is about chemicals.

And, it it not something new. Alexander the Great figured this out way back in 350 B.C. He noticed that plants leaves drooped at night and perked up in the mornings. Soldiers also. More recently, scientists have been able to put a better understanding on what we have known for several thousand years attack just before dawn.

The internal clock in mammals is run by a part of the brain known as the supracinsmatic nucleus. This portion of the brain instructs the pineal gland to secrete melatonin. Melatonin triggers the changes needed to adapt to winter, plus aids sleep control.

Light halts melatonin production. This is one of the reasons you can go fishing after work in July without feeling exhausted.

Rising early in the winter, or staying up well after dark, has our bodies producing sleep-inducing melatonin while we are still up. We are sleepy. Our rhythms naturally shift a bit to compensate and disrupt our sleep cycle with our circadian rhythm. How can overcome this cycle?

Adjusting your diet can help. Stay away from simple sugars like Christmas cookies. Complex carbohydrates are better because they can work on the pleasure sensors in our brains that release dopamine.

Those carbs you are ingesting are going to require some sort of exercise program. Pick something you like to do or odds are you wont stick with it. Get out for a walk. Park your car at the far end of the lot at the grocery store of at work and walk the extra few hundred feet. Look up at the sky and count stars. Find the Big Dipper and Orion. Walk your dog in the morning and evening.

If you cant force yourself to get outside, there is one other solution for the couch potatoes. Spend a few bucks and buy a light box. They are readily available and emit a full-spectrum natural light. Research shows that a half-hour spent in front of a light box, best done in the morning, will reap great benefits in your mental state in overcoming the downside of excess melatonin production.

Get up early, buy the newspaper and read my column in front of the light box. It isnt outdoors, but it is closer than eating corn chips by candlelight.

John Schandelmeier is a lifelong Alaskan who lives near Paxson with his family. He is a Bristol Bay commercial fisherman and a two-time winner of the Yukon Quest.

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Chemistry, not laziness, is why your couch beckons to you during the dark days of December - Anchorage Daily News