Today's #Sleeptember FACT --- The Sun and Moon may not be our circadian systems' only dynamic duo

#SLEEPTEMBER

We've long understood that the rhythms we live by (sleep, wake, hunger, even our digestive system rhythms) are finely tuned to the circadian cycles of the planet which revolve around the daily light-dark cycle and, in the longer view, the seasons.

Now scientists have found a couple of neurological companions in the brain which may also be responsible for turning these cycles off and on via biochemical activity noticed in membranes referred to as ion channels.

Image courtesy www.columbia.edu

As reported in MD, sodium and potassium channels worked in opposition to shift the circadian cycles in both fruit flies and mice. This potentially suggests that circadian rhythms are not only influenced by external forces like light and darkness, but internal processes built into our systems which are entrained to those external forces.

Up to 16 percent of the population struggles with some form of circadian rhythm disorder, according to statistics published by the American Academy of Sleep Medicine. 

That's a lot of people who might have faulty biochemistry when it comes to switching from sleep to wakefulness or mitigating other processes that are information by circadian rhythms.

Ultimately, "[a] better understanding of this mechanism could lead to new drug targets to address disturbances of the sleep-wake cycle, such as jet lag, shift work, and circadian disorders," writes Melissa Glim for MD. "It may become possible to reset a person’s internal clock to match his or her situation." Read more here

Earth Day Tip for Good Sleep...

Happy Earth Day!

Image from the Non-Breaking Space travel blog

If you want an easy way to reset your circadian rhythms, go camping. Sleep under the stars, use a campfire for light at night and keep a flashlight only for emergencies. The fresh air, peace and quiet, and natural shifts between light and dark will do a lot to reset your sleep-wake rhythms to the earth's schedule. Which is what all living things are technically supposed to do... connect to the earth. Get reconnected... pitch a tent!

SHED SOME LIGHT || Insomnia Central: Are insomnia and winter depression linked?

"Sunset Winter" (2007) by Jonathan Hendrick

Insomnia can be its own primary sleep disorder, but sometimes it can also be a symptom of another health condition.

Seasonal Affective Disorder (SAD) is a kind of depression that ebbs and flows based on the changing of seasons. One of SAD's key symptoms is insomnia, which starts out mildly during the transition between fall and winter and which gradually worsens with the further darkening of the days.

(Interestingly, there are some people who suffer SAD only during the brighter spring and summer months.)

The changes in light that come with darker days and longer nights can negatively affect both mood and sleep patterns thanks to impacts on circadian rhythms, which align with the Earth's light and dark cycles.

The reduction in light can also alter emotional chemistry; lower light levels can lead to reduced levels of serotonin, a neurotransmitter which affects mood, resulting in depression. Another neurotransmitter, melatonin, is manufactured by the brain and this process may kick in well before one's typical bedtime as the nights grow longer, which can lead to adjustments in sleep habits that can be disruptive until the transition is complete.

Other symptoms typical to SAD include:

• Agitation
• Appetite changes
• Irritability
• Low energy
• Problems focusing
• Relationship problems
• Sleeping too much
• Suicidal thoughts
• Weight changes

If you have sudden insomnia during the transition between the fall and winter, and you have any of these other symptoms, you are best advised to see a doctor to determine if you actually have SAD instead of insomnia. Your doctor will likely ask a lot of questions and run some tests to make sure your symptoms are actually related to SAD. You could also have chronic insomnia, defined as sleepless nights that recur at least 3 times a week and over a span of 3 or more months.

Keep in mind that insomnia can also be a sign of other problems, including drug interactions or other health conditions you may not be aware you have. Don't presume that because you have some of the symptoms above that you have SAD; let your doctor help you figure that out so you can treat your issues appropriately.

Science on the Subject: 

• Depression and Sleep (National Sleep Foundation)
• The role of beliefs and attitudes about sleep in seasonal and nonseasonal mood disorder, and nondepressed controls (Journal of Affective Disorders) [ABSTRACT]
• Seasonal Affective Disorder: A Review of the Syndrome and Its Public Health Implications (Biology Online) [ABSTRACT]
• Sleep and Depression. (Journal of Clinical Psychology) [ABSTRACT]
• Sleep in fall/winter seasonal affective disorder: effects of light and changing seasons (Journal of Psychosomatic Research) [ABSTRACT]

Insomnia Central || The "walrus"* in space

You'd think it's plenty quiet and dark in space... so how does it happen that astronauts struggle with insomnia?

All living things (including humans, plants and animals) have photoreceptors which recognize the difference between light and dark cycles. These light cues (known in the sleep world as zeitgebers), help us to stay awake during the day and to fall asleep at night. Melatonin production in the brain increases as the sky darkens in the afternoon, then drops off dramatically with the first peek of daylight in the morning.

Astronauts, however, have a different relationship with sunrises and sunsets while working on the International Space Station, where the sun rises and sets every 90 minutes. This rapidly shifting rhythm of light to dark can seriously impose itself on the human circadian system, which is entrained to 24-hour days. Over time, this can lead to hormonal confusion in the brain and, ultimately, insomnia for these space walkers.

Insomniac astronauts are not a good idea. What this could mean is that, during their waking hours, these sleep-deprived astronauts may share a common risk-taking behavior with long-haul truckers, bus drivers and airline pilots: drowsy driving. Lack of quality sleep can result in poor judgment, inability to achieve an appropriate level of alertness in emergency situations, even the opportunity to "sleep drive" (like sleepwalking, but while driving).

Most astronauts end up taking Ambien (aka zolpidem as a generic) to regulate their sleep cycles and comply with their daily requirement of 8.5 hours of sleep, but Ambien can leave them with a foggy morning-after hangover that can impair their performance nearly as much as sleep deprivation. It can also be to blame for some unusual behaviors that can occur while asleep which are typically hallucinatory in nature and may resemble sleep walking.

So which is better... sleep deprived astronauts or hallucinating ones?

Dr Charles Czeisler, a Harvard Medical School sleep expert who co-authored a recent article for Lancet about the problem of sleep for astronauts, said: "Future exploration spaceflight missions to the moon, Mars, or beyond will require more effective countermeasures to optimize human performance by promoting sleep during spaceflight... These may include modifications to schedules, strategically timed exposure to specific wavelengths of light, and behavioral strategies to ensure adequate sleep, which is essential for maintaining health, performance and safety."

So really, the answer is neither. Humans need sleep, even and, perhaps, especially, those who don't have their feet solidly planted on the terra firma.

Read more:

• Sleeping pills in space: Astronauts are regular users || USA Today
• What it's like for astronauts to sleep in space || The Atlantic
• Sleep, the final frontier: Astronauts suffer serious insomnia while in space - and it could be putting their lives in danger || The Daily Mail (UK)

*Ambien is popularly referred to as "the walrus" after a comic strip artist began to write about Ambien experiences in which a "walrus" told him things while he was under its influence.