ABCs of SLEEP || E is for Entrainment

Entrainment is the word scientists use to explain how we all, as human beings, "set our clocks." Our human body clocks, to be specific. Our bodies have multiple "clocks" in specific organs as well as inside each and every blood cell, and like clockwork they help us to manage our daily rhythms, which inform the behaviors that make us functioning human beings.

Think about hunger, sleep, sex, digestion. These are all physiological processes that require some precise timing on the part of our personal clocks. This is what our circadian rhythms are all about. When our rhythms fall out of synchronicity, that is when we can experience disease, general malaise or other kinds of biological confusion. We really can't live healthy lives without adhering to circadian rhythms.

The most obvious way that we entrain ourselves to life's rhythms is through our perception of light. Light is what marks the day/night cycles; the sun rises, the sun sets. Sunlight, and its absence, also helps the body to detect seasonal shifts. These are primal communications we share with the earth. All living things require the light-dark cycles, as established by the rotations of our planet, to manage these critical life rhythms. 

Light is perceived by the eyes, of course, but also through the skin via melanopsin. Signals collected by these organs are sent to the body's main pacemaker, the suprachiasmatic nucleus (SCN), which issues orders to all others parts of the body to function according to a preset pattern of rhythms that, by and large, most human beings are commonly entrained to using light.

For the vast majority of human beings, light is the key influence over when we sleep and when we wake up. For those with circadian rhythm disorders like Non-24 Sleep -Wake Disorder (also known as free-running disorder) or shift work disorder or even a temporary case of jet lag, light doesn't deliver the same influence over sleep-wake cycles. 

The person who suffers from these kinds of disorders struggles to maintain a normal life on an abnormal schedule. They have fallen out of entrainment and need to find a way to "reset" or else they are forced to adjust their schedule in ways that are not typical, even unorthodox, in order to simply get by. 

Imagine the person who can only feel awake and alert in the later afternoon; maybe they have a job working at the toll both during the morning commute. Or imagine the nurse who can only work night shifts but who has children to watch during the day at home. Or the musician who cannot stay awake long enough to attend the gigs he is scheduled to perform at nightclubs. 

Having pattern disruptions in one's rhythms can absolutely devastate the efforts of many to live normally (in this case, meaning "by society's schedule"), and that includes having the ability to earn a living, care for family or function at their maximum potential while on the job. Circadian rhythm disorders also seriously disrupt relationships and social lives.

Non-visual cues

Believe it or not, there are other cues besides light--in science, they call them zeitgebers, which translates as time markers, external or environmental cues that synchronize our biological rhythms--which have a powerful impact on our lives, including our time while sleeping. These are also ways we are entrained to healthy--or unhealthy--rhythms. 

Eating and digesting do not require light or even sight to take place. They require that the gastrointestinal system follow specific cues that dictate that you eat and digest while you are awake. While you sleep, the digestive system goes into sleep mode as well. This is why, generally speaking, most people do not get up in the middle of the night to have a bowel movement. The digestive system does not expect food to enter the alimentary canal at this time. Instead, the act of moving food through the system slows dramatically.

Large meals eaten right before bed, however, can create problems with sleep disruption; the digestive system is suddenly working overtime when it had fully expected to be in bed like the rest of you. Poor sleep can result, as can reflux disease and other health problems related to metabolism. There are lots of studies to suggest that eating out of synch with one's normal body rhythms (meaning, late at night) can lead to imbalanced secretions of certain hormones like melatonin, orexin, leptin and ghrelin, which can impact metabolism in negative ways. 

Finally, there is a circadian shift in metabolism that occurs in the morning as part of your biological rhythms. This is normal; it prompts hunger and stimulates the body to recommence digestion. Now you know why we almost always need to use the restroom first thing in the morning: wakefulness stimulates digestion and the elimination of wastes that have been in your "holding tanks" (meaning, the bladder and the bowel) overnight.

This illustration from the University of Zurich shows how the brain and digestive organs carry their own "pacemakers." The main pacemaker in the body is the suprachiasmatic nucleus (SCN), which is located
deep inside the brain. Its companion pacemakers exist in the digestive system and are driven
by information related to internal cues relayed to them via messages sent by the SCN. 

Activity levels are other non-light time markers that can inform sleep-wake cycles and metabolism. If you exercise too late at night, this could mess with your ability to fall asleep. Physical activity (it could be running a mile or doing laundry) amps up adrenaline and other hormones which encourage wakefulness. 

Similarly, body temperature, which is influenced by how physically active you are, impacts your ability to entrain to patterns that allow for consistent sleep-wake patterns. If you do not get enough physical activity during the day, you may find it hard to fall asleep, as well--with no normal rise and fall in daytime body temperature, the body may not be able to read your activity markers clearly enough to signal sleep to occur. 

Also, the act of sleeping itself is marked by specific patterns of body temperature shifting that prepare the brain and body systems for specific kinds of sleep. If your body temperature is out of whack as you are heading off to bed, you might be missing out on sleep stages that are critical to your body and brain to function at maximum potential.

Temperature-related breaks in entrainment are experienced by people with major stress disorders like PTSD or severe depression: they may generate higher body temperatures at night while in stress response even as they are hoping to fall asleep. Women, because of their monthly cycles, can also experience temporary periods of sleep disruption due to normal alterations in body temperature caused by menstruation or other major changes in hormone balance like pregnancy or menopause.

SHED SOME LIGHT: Sleep Hygiene Tip of the Week: Managing jet lag while traveling over the holiday

"Over the river and through the woods to Grandmother's house we go..."

NOT... Grandmother lives in Miami and you live in Denver. Your siblings and their families live in Fargo; Trenton, New Jersey; and Memphis.

"Nightly Rotation Above San Jose International
Airport" (2005) by Wing-Chi Poon. CC:ASA-2.5 Generic.

These days, airlines have replaced the old-timey sleighs that carted families from one town to the next for special occasions like Thanksgiving.

If you are someone who lives far away from family and must rely on flights to be reunited, then you likely admire those who only have to make the quick drive across town or even the few hours on the highway.

Traveling in the winter, especially, takes extra time and extra energy to sort through all the delays that might arise due to weather and overbookings.

What makes things worse is that every time you hop a time zone (forward or backward), you confuse your body clocks. The more time zones you cross during a continental flight, the more confused your body clocks will be.

Your main clock, located in the suprachiasmatic nucleus in the brain, will find changes in light exposure (too little when the brain expects there to be light, or too much light when the brain expects there to be little) overwhelming.

It's not a force of habit that leads to the symptoms of exhaustion that we have come to term jet lag, but actually a reshuffling of chemical balances in the brain, which has been confused by these external queues and suddenly cannot reset itself accordingly. It is essentially out of rhythm with the rest of the body.

Circadian rhythms are informed by the light and dark cycles of the earth. They also take their cues from our activity levels (the body naturally is more energetic in the morning and less energetic in the evening, for example) and our eating habits. Our digestive system does not expect to be processing a main meal several hours before or after it normally does this task; meals eaten much later than normal are especially troublesome because that is when key organs in the body, which operate on their own clocks--which are synchronized to the main clock--are trying to rest.

What this all amounts to is a sense of disorientation, however temporary, plus feeling less than 100 percent. Fatigue, gasiness and bloating, dehydration and insomnia can all be side effects from hopping time zones.

Technically speaking, jet lag has been taken off the list of circadian rhythm disorders because of its temporary nature... everyone eventually recovers from these shifts in the body's rhythms when they return home. That doesn't make it easier to manage during stressful times like the holidays, however.

There are ways to help yourself so that these feelings of travel-related malaise aren't quite so extreme.

• Drinking water before, during and after the plane ride (and not coffee, alcohol or soda) will help keep your body in balance through changes in temperature, climate and cabin pressurization. In fact, most of your discomfort from jet lag will come because of dehydration.
• How many hours are you traveling east? Three? Then start shifting your schedule by going to bed a half hour earlier on Saturday, then an hour earlier on Sunday, then an hour and a half earlier on Monday, two hours earlier on Tuesday, two and a half hours earlier on Wednesday. Reverse this plan if you are traveling west across three time zones. It may seem extreme but if you really need all your energy for the holidays themselves, you will thank yourself later for planning ahead so you won't need to endure the fatigue/insomnia showdown that can come with jet lag later.
• On your travel days, curb your eating. Don't eat a big meal before getting on the plane. Try not to eat a full meal on the plane, as well (a snack would be okay if you really are hungry), then wait until you are off the plane. Once you are at your destination, eat only during the local meal time. This will make it easier to adjust for the holidays when you really want to enjoy those family meals together.
• Use earplugs, eye masks, blankets and neck pillows to sleep comfortably on the plane, should you be traveling during a time you would normally sleep. However, try not to oversleep on the plane; only sleep when your body needs it or you might rob yourself of your sleep drive prematurely.

Sleep Hygiene Tip of the Week || Melatonin is tricky

"Walgreens Melatonin" (2010) by Jed Carroll,
UK. CCA:2.0 Generic. Publication of this
image does not imply endorsement of this
or any products by SleepyHeadCENTRAL.

The seemingly kneejerk practice of automatically turning to medications to treat health disorders, even over-the-counter supplements (which are essentially unprescribed drugs), is a discussion for another time.

Over-the-counter sleep aids that are touted for their sleep-promoting properties (namely diphenhydramine, valerian and melatonin) have their fans and detractors, as well.

For this week's tip on sleep hygiene, melatonin is going to nab a little of that spotlight.

Some people LOVE using melatonin and swear by it for their problems with falling asleep or maintaining sleep. Others find it useless.

Sleep science is not conclusive on the benefits of melatonin, either. Melatonin dosages currently available from the drugstore may or may not be adequate. Also, melatonin requires a very careful schedule of dosing for it to work, and that schedule will depend entirely on the individual using it.

SHC maintains the policy of asking your doctor for advice before using melatonin, and if you should decide to go this route, to seek exact advice regarding timing and dosage from a medical professional. With any medication or supplement, there can be side effects as well, so please look at this aspect of melatonin use before taking this popular sleep aid.

Below are some articles that help explain how and why melatonin works (or can work) and why it may or may not be for you.


YourSleep || AASM.net
Over the Counter: Will Melatonin Cure Your Sleep Problems?

Natural Practitioner
Monograph: Melatonin

Drugs.com
Melatonin

Wellness || Cleveland Clinic
Melatonin Supplement Review

Drugs and Supplements || Mayo Clinic
Melatonin (N-acetyl-5-methoxytryptamine)

SHED SOME LIGHT on CIRCADIAN DISORDERS

In order to understand what a circadian rhythm disorder is, you need to know what circadian rhythms are.

Circadian rhythms are also referred to collectively as "the body clock," as they mark the way in which the human body processes time cues from the environment. These time cues include sunlight and seasons and temperature changes.

Our bodies are influenced strongly by these exterior cues, as they help to inform many internal processes in the human body as well, including sleep drive and digestion, among other things.

Hence, our bodies cycle in tandem with these rhythms, which occur following the same 24-hour pattern that represents one Earth day.

Think about it: The typical human being rises with the sun and goes to bed after the sun has set. When this very basic programming of the human body is diverted, many basic biological functions can be changed, thwarted or otherwise negatively impacted.

Research into sleep health and circadian rhythm dysfunction continues to show consistently how these kinds of disruptions to our rhythms can lead to cardiovascular problems, slower metabolism (leading to obesity), higher risk for cancer, and connections with mental health problems.

Some common circadian rhythm disorders can come as the result of lifestyle choices: jet lag occurs because of air travel across time zones, and those who work the graveyard shift can have a hard time achieving "recovery" sleep after working long overnight hours.

But some circadian rhythm problems are the result of internal disruptions.

Teenagers often has delayed sleep phase disorder, in which their drive to sleep launches later in the evening than their younger or older peers; these changes in "sleep phase" are brought about by chemical responses inside the bodies of teens that relate to their rapidly changing brain and body biology.

Keep in mind, delayed sleep phase problems are not just reserved for teenagers, but for anyone who can't fall asleep at a "typical" hour. Extreme night owls of all ages can find this problematic for keeping morning appointments or getting to work on time if it means they must cut short their nightly sleep due to delayed sleep phasing.

Elderly people often have advanced sleep phases, the opposite of what adolescents experience, which can explain why they are in bed by 6pm at night.

But again, people of any age can also suffer advanced sleep phasing, which can get in the way of work and family life as it often means these people cannot stay awake to participate in social time or work shifts that are scheduled in the early evening.

In addition, there are people whose rhythms do not match the 24-hour cycle... their days are typically longer than 24 hours, and this makes it difficult for them to live normal lives. They suffer because their sleep-wake cycles can become extremely desynchronized with the rest of the world.

Finally, the person who suffers from irregular sleep-wake phase suffers from the interruption of at least 3 sleeping periods during their waking day.

You can see how having intrusive periods of sleep or wakefulness at the wrong times of the day can make life hard for some. Employers and educators function on fairly regular working periods, so jobs can be hard to keep. Falling asleep at inappropriate times can be embarrassing, can lead to relationship stress, and can keep circadian rhythm disorder sufferers from leading full lives; they might even be dangerous.

Employers are starting to honor flex hours to respond to the needs of those who have dysfunctional circadian rhythms. Scheduling in hospitals and other workplaces where 24-hour shift work is the norm can help to give these employees a fair chance to recover from their overnight schedules so they can be better, safer workers. It's not unheard of for corporations to now have a nap room available to those who may need to catch a few midday winks.

Later school start times are one attempt to help teenagers to endure their naturally later sleep phases so they can be more productive and alert in class and so that they can avoid the sleep deprivation that delayed sleep phase can cause, which can lead to automobile accidents from drowsy driving and poor decision making in social situations.

Still, families can struggle when one or more members has a circadian rhythm disorder. Circadian dysfunction can lead to misunderstandings, unfounded assumptions about laziness, concerns that the sufferer has mental health problems, and mistakes that can make a home unsafe (kitchen fires, bad falls, and harm to unsupervised children are all potential risks).

To learn more about circadian rhythms, please visit the Circadian Sleep Disorders Network for in-depth information on each of these conditions and for resources for treating these conditions and raising awareness.

Sleep Disorders 101 || What is Jet Lag Disorder?

Dry, bloodshot eyes can also
be a symptom of jet lag

Anyone who has traveled by air across time zones can relate to the some or all of the symptoms of Jet Lag Disorder, which can include:

• Disturbed sleep patterns (you can't sleep, you wake up too early, you experience excessive sleepiness during nonsleep periods of the day)
• Fatigue
• Trouble with focusing, attention, concentration on typical tasks
• Digestive issues (constipation or diarrhea)
• Heavy menstrual cycles
• General malaise
• Tired muscles

Jet lag is a temporary circadian rhythm disorder in which your body fails to acclimate immediately to a new time zone, leading to these potential symptoms. Generally it occurs after you cross more than two time zones. When you move forward or backward "in time," you are also moving forward or backward through cycles of sunlight, which is really where the problem comes in. Jet lag is about both time (your "body clock") and light. All living things entrain their sleep-wake (or active-inactive) rhythms to the rise and fall of the sun. Changing time zones means you are experiencing different blocks of both time and light than your body and brain are accustomed to. Another part of the brain, the pineal gland, requires exposure to light in order to produce melatonin, the hormone that helps you to fall asleep. If your travel times are at odds with your sleep patterns, it could be due to an imbalance in melatonin production caused by traveling across time (and light) zones.

Your body has a main biological "clock" in the brain--the Suprachiasmatic Nucleus or SCN--which notifies many other systems about what "time" it is. Indeed, each and every cell in your body is theorized to have its own body clock, which synchronizes with the SCN.

The digestive system is also thought to operate by its own clock, using both food consumption and light to set body rhythms in such a way as to conveniently limit digestive processes while you sleep. This is why you might, in fact, have digestive problems as a result of jet lag, as the digestive system clock is not in sync with SCN.

Having jet lag can be problematic because the times you are accustomed to eating or sleeping may not fit comfortably inside your new schedule. You may be excessively tired in the day just as everyone else is going outside to enjoy the day, or you may want to eat an overlarge meal in the middle of the night.

Jet lag symptoms typically set in within 24 hours of arrival at your destination. The farther you travel, the more severe or long-lasting your symptoms can be. Easterly travel usually results in more severe symptoms when compared to westerly travel, as well.

Researchers indicate that it takes about a day to recover for each time zone crossed. If you crossed five time zones, for instance, it will take you five days to recover from jet lag, either because you have acclimated to the new time zone or as a result of returning to your home time zone. Don't worry too much; for most people, jet lag is temporary and repairs itself. In their case, it's not a disorder at all, but a problem that fixes itself.

However, if you're a pilot or business traveler who flies frequently, Jet Lag Disorder can become an ongoing problem for you. Elderly people can also require more time to recover from jet lag as well.

If you want to avoid the symptoms of jet lag, you can try the following:

1. Carefully time your light exposure in the new time zone to "reset" your rhythms. Wear sunglasses in the morning on eastern time and in the afternoon on western time to trick your brain into resetting its rhythms.
2. Drink plenty of water; air travel can lead to dehydration which can then exacerbate many other kinds of problems, including jet lag.
3. Avoid caffeine, alcohol, stimulants and sedatives while in the air. For sedative or stimulant prescriptions, it might be better to start take them on local time when you arrive at your destination. Taking them while traveling in flight can aggravate jet lag as well.
4. Be prepared to adjust immediately to the local light and time zone you arrive at and expect to take a day to feel out of sorts.
5. If you are traveling for an important event or meeting where you need to be alert, you might wish to travel two days ahead in order to have time to adjust prior to your appointment.
6. Pharmaceutical treatments for Jet Lag Disorder including pharmaceutical options (sedatives such as benzodiazepines--so-called "Z" class drugs such as zolpidem [Ambien]-- and nonbenzodiazepines--triazolam [Halcion]). Remember, drugs can have side effects.
7. Light therapy, which involves timing your exposure to specific kinds of light using special lamps at certain times of day, can be a great non-drug alternative. There are travel lightboxes specifically used for this. 
8. Alternative treatments for Jet Lag Disorder include melatonin (you only need .5mg for it to be effective, despite over-the-counter doses of 2mg or more) and certain proprietary herbal blends (often including valerian, GABA or skullcap). The key to using melatonin is to time it with the dimming of daylight so your pineal gland can operate more efficiently. As for herbal blends, please check drug interactions and side effects before you take them as they can be dangerous if mixed with certain prescriptions.
9. It is always more important to wake up at the same time of day than to go to bed at the same time of day. This is because your exposure to morning sunlight helps set your wakefulness drive for the rest of the day. While traveling, you might try to artificially "reset" your rise time while in another time zone to match the one you have at home in order to help lessen the impact of jet lag.
10. While there is no official "jet lag" diet, it's good to practice eating more carbs before periods of sleep and protein rich foods during the times of day when you want to be most awake.
11. It's never a bad idea to sleep a little extra prior to traveling to lighten your sleep debt before you head out.
12. You can try to stay up later gradually, prior to your trip, for westerly travel, or go to bed earlier, prior to your trip, for easterly travel, to make the transition easier once you arrive.
13. Sleep on the plane if you expect to arrive at night anyway. This can help reset your sleep drive.