Column: Your internal clock

It always annoys me when wintertime comes around, slashing our daylight hours to the point where by the time six o'clock rolls around, and it's pitch black outside. By then, the dark makes me think I'm sleepy and I want to just lay right down and go to bed even though I got a full eight hours of sleep the night before.

After looking into this a little more, I found it had to do with your internal clock, or circadian rhythm.

According to WiseGeek, your internal clock is a term used to describe the approximately 24-hour cycle that is inherent in most living entities. Humans aren't the only ones with this fascinating feature - plants and other mammals do as well.

A person's rhythm is more or less constant, with different internal and external factors affecting your particular rhythm.

An example of how circadian rhythm affects people is taking the red-eye flight home and discovering the annoying effects of jet-lag. Also, many times new employees on the night shift have a hard time adjusting to the different sleep cycles their job has forced them to embrace.

Frank A.J.L. Scheer, an Assistant Professor of Medicine at Harvard Medical School, found that in humans, the internal clock is located in the hypothalamus in the brain.

Your internal clock can be adjusted to the environment by outside factors called zeitgebers, the most significant of which is daylight.

Without daylight, the biological clock will eventually start running on its own natural cycle...but as soon as morning light hits the eyes, the clock will reset to match the Earth's 24-hour day.

A normal day usually consists of higher body temperature, blood pressure and cortisol horomones (involved in response to stress and anxiety), and vice versa for a normal night.

Our human circadian rhythm is not exactly 24 hours – in fact, it's 10 – 20 minutes longer. Other species have rhythms ranging from 22-28 hours.

Here's some great news: according to "The Prevalence of Daytime Napping at its relationship to Nighttime Sleep," by June Pilcher, a number of studies have concluded that a short period of sleep during the day, like our beloved power naps, do not have any effect on normal circadian rhythm - on the contrary, it helps decrease stress level and improve productivity.

Finally, here's another reason not to do drugs – genetic manipulations of clock genese profoundly affect cocaine's actions.

So the next time you want to sleep during the day, I would recommend draping your snuggie over the windows for complete darkness – for the full effect. Or, if you're studying late at night, turn on plenty of lights so your eyelids don't start getting droopy.

Oh, and p.s. -

For the past four years it has become increasingly evident that my college career has greatly been impacted by my utilization and fondness of Polar Pops from Circle K. I'm not sure what I did before Polar Pops – they have the same impact that cell phones have on me...and now I'm not sure what I'd do without them. I know I speak for more than just myself when I say I wish they still had those cherry shots behind the counter.