By Allison Ford, DivineCaroline
During this time of year, itís hard to not be jealous of the various squirrels, hedgehogs, possums, chipmunks, bats, skunks, lemurs, and other small mammals that lower their body temperatures and their metabolisms for the winter, napping in their burrows until the snow goes away. Bears donít exactly hibernate, but they do spend winters in their dens, napping and caring for newborn cubs. Even some species of reptiles and amphibians hibernate, remaining in a sluggish torpor throughout the winter when thereís not enough heat to raise their body temperatures.
Humans, of course, do not hibernate, but it can feel much more difficult to get out of bed on a chilly winter morning than it does in the height of summer. Some people take this as a welcome sign that being awake during the winter is an affront to nature. Or at the very least, they assume that humans need more sleep during winter. Is that true?
The Straight Talk
We donít exactly need more sleep during the wintertime, but due to factors beyond our control, we definitely want it.
Humansí sleep and wake cycles are regulated by light. Light suppresses the production of melatonin by the brainís pineal gland. As daylight fades, the pineal gland produces more melatonin, which causes us to feel sleepy. In the morning, the gland is instructed to stop producing the hormone, which aids in waking up. We feel sleepier in the winter because thereís less daylight, hence more melatonin. We wake up when itís still dark outside, before the pineal gland has been instructed to shut down, and it starts up again long before weíre actually ready to go to bed. That adds up to many lethargic mornings and evenings.
Another dirty trick that makes us want more sleep is that wintertime affords us with prime sleeping conditions. Itís dark outside and the house is cool and stillóa perfect recipe for a good nightís sleep. No wonder so many people have trouble leaving bed on a January morning.
Although many people end up waking later and retiring earlier during the cold, dark months, thereís no real biological need for getting extra sleep during the winter. Thereís more variation in sleep needs among individuals than there is in a single individual between seasons. That is, some people naturally need more sleep than others need in order to function optimally, and that number doesnít change with the seasons.
Even though our body clock is triggered by light and dark, our sleep needs donít correspond exactly with the length of the days. Think about it: in Scandinavian countries where there may be only a few hours of light per day in the winter, people donít suddenly need eighteen or twenty hours of sleep per night. Likewise, in the summer when there are only a few hours of darkness, people arenít suddenly able to get by on only two or three hours.
The imbalance of light and dark is a prime culprit in the development of seasonal affective disorder (SAD), a wintertime malaise characterized by fatigue, depression, and weight gain. Sound familiar? Itís no coincidence that treatment for SAD commonly includes light therapy to reset and regulate the bodyís circadian rhythms.
If youíre already getting your optimum amount of sleep, you donít need extra just because itís winter. But if you regularly donít get enough, feel free to fight the freeze by staying snug in your bed as long as possible.