Category Archives: Uncategorized

Understanding Circadian Rhythms at the Molecular Level

We’ve talked in the past about circadian rhythms, how there is a daily rhythm of hormone fluctuations that make us more alert during the day, and more sleepy during the night. There are also changes in organ function by time of day. Shiftworkers’ health suffers for being up and active at a time their body is programmed to sleep.

What we haven’t discussed is how these rhythms are established in the first place. Just this week, there was an article published in Science by Lazar and Feng about the circadian rhythm of fat metabolism in the liver.

During the day, molecules modify the liver DNA to reduce fat production. Those molecules leave during the night (so there are 100 at 5am, as opposed to 15000 at 5pm). With those molecules absent, more fat is produced and stored in the liver. The authors conclude “This leads to a circadian rhythm of metabolism that is important, because disruption of this rhythm leads to fatty liver. This may explain in part why altered circadian rhythms in people who do shift work is associated with metabolic disorders.”

There are molecular changes like this happening in many organ systems, multiplying the effect of being out of sync with the natural light-dark cycle.  As our understanding of circadian physiology develops, we’ll be better able to improve the health of shiftworkers.

Teens Bedtimes Influence Depression

So, we’ve known for a long time that there’s a connection between sleep disturbance and mental health, particularly depression.

There’s been some research published this year looking at the connection between teens’ bedtime and mental health. Because depression may affect a student’s chosen bedtime, this study looked at parentally set bedtimes. Students’ were divided into two groups – bedtime 10pm or before, and bedtime midnight or later.

The teens with the later set bedtime of midnight or after were 24% more likely to be depressed and 20% more likely to have suicidal thoughts. The students with depression and suicidal thoughts had a sleep duration of 7 hr 23 mins compared to the other adolescents with an average of 7 hr 55 mins sleep nightly. Note for all groups this is at least an hour less than the recommended sleep for teens – 9 hours of more.

The authors conclude that an earlier parentally set bedtime may be protective against depression and suicidal thoughts in teens since it provides a longer sleep duration. Something to think about for all parents and people working with kids.

Skills for Falling Asleep

There are many ways a person could experience insomnia. It could be difficulty falling asleep at the beginning of the night, or being awake for an extended time in the middle of the night, or waking too early.
Whatever time it is, being awake in bed can often lead people to feel frustrated, angry or hopeless about their sleep. As you can imagine, these feelings do nothing to help a person fall asleep. Let’s talk about some strategies to use to help yourself fall asleep.

An ‘Over-active’ Mind
Frequently people tell me that their mind is going a mile a minute once they are awake in bed, that they have ‘buzz brain.’ In this situation, you want to establish boundaries with yourself that bedtime (from lights out to wake time) is not a time to think things through.
So first of all, schedule time 2-3 hours before bed to jot down the thoughts that arise at night, and put them to rest. Spend just 10 minutes on this, so you don’t get further entrenched in those thoughts. You can use any format that works for you – a To Do list, journal, problem and solution brainstorming list, calendar system, or any other format.
Second, if thoughts arise in the night, tell yourself that you already thought about it, and will have time tomorrow, now is time to rest. Putting your thoughts aside like this is a skill, and like all skills, you will get better the more you practice.
Follow this up with purposefully substituting thoughts that help put you to sleep. Some strategies are: a sleep promoting visualization (think dozing on the warm sand at the beach), or slow deep breaths, or repeating a prayer or mantra. For people who are also physically restless, doing progressive muscle relaxation starting with the feet can help still both the body and mind.

Concluding Thoughts
Almost everyone has difficulty sleeping occasionally, and these strategies can help quiet the mind and promote sleep. Establish with yourself that during your sleep time you are “off duty” from all types of thinking or planning. You will feel better for having a good nights sleep, and be better able to think things through well during the day.

Women’s Sleep Health

It’s when reproductive years begin that women begin having more sleep problems. Here are some common sleep disturbances by hormonal status.

During the premenstrual week, women report having more difficulty falling asleep, sleeping through the night and waking in the morning. It’s common in the office for women to say “The week before my period I need more sleep.”

During pregnancy sleep changes each trimester. During the first trimester women typically need more sleep, and find themselves sleepier during the day. Sleep improves during the second trimester, generally speaking. Symptoms of reflux, leg cramps, frequent urination, and simply being uncomfortable lying down disturb sleep in the third trimester.

During menopause, women’s sleep can be disturbed by hot flashes and night sweats. Also, as part of the aging process, sleep is lighter with more awakenings. It is also important to know that sleep disordered breathing (such as snoring and apnea) becomes more common in women after menopause.

What can I do to improve my sleep?
If you are experiencing sleep problems common to women, here are some tips to help yourself sleep well all month:
– If you need to, allow yourself extra sleep time during the week before your period, so you can feel more energetic and less sleepy.
– If you are having night sweats and getting too hot at night, take steps to keep cool. (Remember, people tend to sleep better when they are cool). So turn the thermostat down, layer blankets so you can easily adjust them, and wear fabrics that wick heat and moisture away from your body. Be creative with your bedpartner in finding a solution to keep both of you at a comfortable temperature. Several patients have recommended specialty products, including those from Wild Bleu and Opposheets.
– If you are having hormonal problems, see a naturopathic physician who can develop a treatment plan for you to better moderate your hormone levels.
– If your sleep continues to be disturbed, you may have another sleep disorder, or need specialized treatment from a sleep center.

Are you an Owl or Lark?

An ‘Owl’ is someone whose body clock is set to sleep later than average, and a ‘Lark’ is someone whose set to sleep earlier than average. It is your inherent melatonin rhythm and temperature rhythm that determine when you sleep.

Being an Owl or Lark can impact how well you do with different schedules. Generally speaking, Owls do better with later schedules and shift work like graveyard. Larks are the ones you’d want to open the shop in the morning. It’s important to know that alertness fluctuates over the 24 hours in almost the same curve as temperature. As your temperature drops you are less alert and more sleepy.   If you get into bed and try to sleep before your body is ready, you may experience this as insomnia.  About 10% of chronic insomniacs actually are Owls, and if they go to bed later have no problem sleeping.

To determine if you are an Owl or Lark you can do the Horne-Ostberg Morningness-Eveningness questionnaire, which was developed in 1976. You can find a modified version of it online at http://web.ukonline.co.uk/bjlogie/test.htm.

This information can help you develop a lifestyle that best suits your circadian rhythm.  If you are not able to shift the time of your commitments, a sleep specialist may be able to help shift your circadian rhythm.

Sleep Tests during the Day?

Sometimes people also need to have their daytime sleep tested. There are two main tests, the Multiple Sleep Latency Test (MSLT) or the Maintenance of Wakefulness Test (MWT). In sleep centers the MSLT used primarily, so that’s the one we will discuss here.

The MSLT is conducted the day following an overnight study, and begins 2 hours after waking. Patients should sleep on their regular schedule the night before, and get dressed for the day. The patient lies down in bed, and allows himself to fall asleep. After 20 minutes the nap test is over. The test is repeated every two hours for a total of 4 or 5 naps. The data from all tests is averaged.

The sleep specialist is measuring how long it takes the patient to fall asleep, and whether the patient had REM sleep. This helps assess how sleepy the person is. It is considered normal to fall asleep in 15 minutes, sleepy if sleep occurs in less than 10 minutes. Narcolepsy is characterized by a sleep onset of less than 8 minutes, with 2 sleep onset REM periods. We’ll talk more about narcolepsy in the next post.

How to Have a Good Night at the Sleep Center

First of all, know that almost all people sleep just fine in the sleep lab. Before and during medical school I worked as a PSG tech, so I know this is true from seeing hundreds of people sleep well.
You’ll be asked to arrive at the lab about 7pm. You will work with one staff called a PSG Tech throughout your stay. He or she will show you the bedroom, and hook the testing equipment to you. They will monitor you throughout the night and unhook the testng equipment in the morning. If you need to use the restroom in the night, no problem, simply call out to let the Tech know.
Most sleep labs have bedrooms that look like hotel rooms with a double or queen-sized bed. You are welcome to bring your most comfortable pillow, and a favorite book or movie to enjoy before bed.

Keep in mind the information gathered during the overnight sleep study is so valuable in diagnosing and treating sleep problems that it is well worth it.

Sleep Study Data

What data is collected during the sleep study?
There are thin electrodes placed on your scalp with paste, at the outer corner of each eye, and on your chin. These are used to determine whether you are awake or asleep, and what stage of sleep you are in.
Additional testing equipment includes elastic bands around your chest to measure your breathing effort, EKG pads on your chest to monitor your heart, and electrodes on your legs to monitor leg movements. You will also have a sensor on one finger to measure your blood oxygen level.

From this monitoring equipment physicians can see how your sleep cycles looked, and percentage of each sleep stage. Also can see if you had any sleep breathing or movement disorder, or other more rare sleep disorder.

Next blogpost we’ll talk about ways to be most comfortable during the overnight sleep test.

When Do I Need a Sleep Study?

Sometimes people who are sleeping poorly don’t know whether they need an overnight sleep study or not. The sleep study is also called polysomnography, or PSG for short. There are about 80 sleep disorders. Some of these sleep disorders require an overnight sleep study, though many do not. Here is a list:
Sleep study is NOT required for:
• Insomnia
• Circadian Rhythm Disorders such as Delayed Sleep Phase Syndrome
• Most Parasomnias
• Some Hypersomnias such as
• Some movement disorders such as Restless Legs Syndrome

Overnight sleep study IS required for:
• Sleep disordered breathing, including Sleep Apnea
• Periodic Limb Movement Disorder
• Some Parasomnias, including REM Behavior Disorder
• Narcolepsy

Next blog post we’ll continue this discussion by describing exactly what data is collected in the sleep study.

Children’s Sleep and School Success

Children’s Sleep and School Success – How they are related
School start is on the horizon. For those with children this can be a busy time, doing those last minute summer activities, getting school supplies, and preparing children for a successful year. Let’s take the time to get children on a good sleep schedule that will help them in school.

Children’s Sleep
Why is it important to think about children’s sleep? To start, many children simply don’t get enough hours of sleep. Here’s how much sleep kids need:
• children 3 to 5 years old need more than 11 hours
• children 6 to 12 years old need 10 to 11 hours
• teenagers need 9 to 9.5 hours
Looking at the school start times here in Seattle, and allowing just one hour from wake-up to being at school, grade school children should be sleeping by 9pm, middle schoolers by 9:30p, and high school students by 9:30-10pm. (If your child needs more than 1 hour from wake-up to school start time then move bedtime earlier accordingly). Are your children getting to sleep at that time? If not, your child is probably feeling the effects of insufficient sleep.
Impacts of Insufficient Sleep
Going to school can be demanding, children are asked to concentrate, learn physical skills, and develop socially with their peers. Here are some highlights:
• Only 20% of children grades 6-12 get the necessary amount of sleep (>9 hrs)! Can you believe it?! In younger children, only 47% get the sleep they need.
• Increased playground injuries in children who sleep <10 hours.
• Children with insufficient sleep are more likely to be angry, depressed, or overly emotional. Kids who sleep less take more risks, and this is especially true in teens.
• Cognitive effects include impaired memory, creative problem solving, and decreased verbal fluency, all skills that your child needs in school

What you can do to improve your child’s sleep:
• Establish bedtimes for your children, so everyone in the household knows the standard. You may want to have a time when everyone finishes their activities and starts to “wind down.”
• Start a trend in your social group of starting activities early enough that they usually end an hour before bedtime. This gives you time to travel home safely, and wind down a little before going to sleep.
• Remove electronic media from your child’s bedroom so they are not tempted to continue with homework, TV, or texting after bedtime
• Kids (and parents) can get excited about activities. Emphasize quality wake hours rather than quantity. Is it really fun to stay up late if you are so tired that you can’t think or are teary the next day?
• Allow your children to catch up on sleep on the weekends or vacations if necessary. The golden standard is to wake up on their own, feeling refreshed and energetic throughout the day. If your child sleeps a lot more on weekends, consider moving their school night bedtime earlier in 15 minute increments until it evens out.