So You Want to Hibernate…

If you have to wake up before 7 am in Winter, when the sun may or may not be up and your room is cold, you’ve probably contemplated hibernation. Sweet, sweet hibernation. However, before you take the plunge into temporal heterothermy, there are some things you should know.

First and foremost, temporal heterothermy is the internal maintenance of a high body temperature only for certain time periods. For most hibernators, these time periods are Spring, Summer and Fall (for the most part, but I’ll get to that). If you’re serious about hibernating, you need to spend Fall bulking up on unsaturated fats. This is to prepare for food scarcity in Winter/when you’re asleep and is not for the faint of heart. If you can’t pack on the pounds and increase your weight by at least a third, then hibernation is not for you. Because even with a lowered metabolism, that is about how much weight you’ll lose just while sleeping. Without those extra pounds, your body weight could drop dangerously and when/if you wake up in Spring, you would NEED to find food the minute you woke up. Not exactly an ideal scenario, so if you can’t pack it on, pack up and migrate South for the Winter.

If you think you can prepare for hibernating, then you need to know what it will actually entail. Yeah, it’s a lot of sleeping, but your body is pretty busy the whole time. The hypothalamus, which controls various bodily set-points like thirst and hunger, also controls your temperature set-point and will greatly lower this during hibernation. Right down to 0˚ C/32˚ F. Sound a little familiar? Perhaps you’re thinking of torpor in bats (Batter Up). Torpor is very similar, but a body in torpor is basically ectothermic and will drop to ambient temperatures. A hibernating body still regulates temperature, even if that set-point is very low. Furthermore, hibernators will have warming periods during their sleep, likely to prevent freezing but also possibly to briefly wake up for a mid-Winter snack. To accomplish these warming periods, hibernators utilize special proteins in brown and white adipose tissue (Remember brown fat? Bite of Fat) called uncoupling proteins (UCPs) to turn energy from ion flow in adipocyte mitochondria (fat cell mitochondria) into heat.

True hibernators include small mammals lie the Arctic ground squirrel but, contrary to popular belief, not bears. Bears can’t cool off and heat up like that, they’re just too damn big for that to be practical. They literally sleep through the Winter, with their bodies only cooling off a little the whole time. So consider that an option if true hibernation does not sound right for you.

And as always, talk to your doctor before making any drastic decisions regarding your thermoregulation.

What are you doing polar bear, you do not hibernate at all

Sources

Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.

Be My Night Owl

I am not a morning person. Not now, not ever. I have punched a man for waking me too early (not intentionally, but still). You can imagine my sparkling demeanor when I awaken at 5 am each morning for work. But why is this? Why does my sense of humor disappear and leave a cranky, swearing, unkempt woman in a retainer behind? Circadian rhythm. No, that’s not something you should have studied for music theory, it’s the technical term for your “body clock”. And how does that work? Sit still and I’ll tell you.

First, let’s talk genetics. New research suggests that genes determine whether you’re a morning person or, like my father and I, are inclined to strangle overenthusiastic roosters and alarm clocks. These genes are likely related to clock protein and melatonin production (not to be confused with melanin, which is in your skin). Clock proteins are synthesized during the day and accumulate around the nucleus (site of DNA storage) of the cells in the superchiasmatic nucleus (region of the brain, just call it the SCN and don’t worry about it), at the end of the day the nucleus takes up the proteins and by the next day clock protein synthesis begins anew. Conversely, melatonin is secreted by your pineal gland (gland in the middle of your brain) at night. Secretion will vary depend on the season, but the general rule is that at night secretion is around 10 times that during the day. When you wake up in the morning, photoreceptors your eyes pick up the signal and transmit it to the SCN. These photoreceptors possess light sensitive proteins and are different from the rods and cones processing the light cues from those kitten pictures you have open in the other tab. Their light sensitive proteins do not aid vision, but instead receive light and use it to signal the SCN. The SCN will then alert the pineal gland and melatonin production will drop off. However, if you wake up before the sun (like me) it gets a lot harder to wake up fully, quickly. On a good day I’d say it takes an hour or so before I feel truly awake and alert. Thank God for long commutes. As I’ve gathered from my reading, research has not specifically outlined the biological difference between early and late risers. After a certain point, everyone is getting the light cues to wake up, so why the lag? Likely (and this is where I’m making my own inferences) late risers need stronger light to halt melatonin secretion, while early risers need only a little.

So I am fated to be forever a cranky. Of course, proper attitude (not focusing on sleep or resenting consciousness) helps IMMENSELY. As does getting some exercise so I’m tired at night. And yet…

Doom to all who disturb my slumber.

 

Source

Sherwood, Lauralee, Hillar Klandorf and Paul Yancey. 2005. Animal Physiology: From Genes to Organisms. Thomson Brookes/Cole, Belmont, CA.