Archive for the ‘body clock’ category

Light Impacts Sleep

November 7, 2014

Now that the nights are longer, it’s time to think about the impact light has on our sleep. And oh, does it have impact! This last month it’s been a pleasure to read two books on light, and human’s historical experience of night – The End of Night by Paul Bogard, and At Day’s Close Night in Times Past by A. Roger Ekirch. Let’s dive into some of the details, and then how you can design light exposure to help your sleep.

The negative effect of light at night
Roger Ekirch talks about the human experience of night over the centuries. Streets until the 1600s had only the light spilling from homes to light them. To be out at night was dangerous, and many towns would close their doors at night and enforce a curfew. For safety, fires and candles would be put out before bed. Their use would be conserved to save money, so some poor people would go to bed soon after dark.

Compare that history to the “sky glow” that many of us are now living in, where we can hardly see the stars at night. In The End of Night author Paul Bogard outlines what is lost when we no longer have dark nights. Not only is human physiology influenced, but migrations of birds and the life-cycle of trees is altered.

Melatonin is a hormone secreted by the pineal gland of the brain. Melatonin is nicknamed “the hormone of darkness,” and helps us feel sleepy at bedtime. Unfortunately melatonin is very sensitive to light, particularly blue light, which suppresses it’s release. And what are 90% of us exposed to during the evening? The blue light of electronics which suppresses melatonin!

The positive effect of light during the dayA recent study compared the sleep of office workers who get natural sunlight to those who work on the interior of the building and don’t. Those who got more light during the work day had better sleep quality, slept longer, and had more physical activity. They also reported a higher quality of life – something we’d all like!

Using light exposure to improve sleep
The basic principle is to get historical light levels during both day and night. In other words, bright full-spectrum light it the morning and during the day, then full darkness at night. How can you do that? Here are some ideas:
– in the morning get some bright outdoor light as soon as possible. Maybe go stand on the porch and look out while having your morning tea.
– continue to get bright light in bursts throughout the day
– in the evening, have lights low, and use the yellow-red spectrum if possible (rather than blue or full-spectrum lights). Avoid electronics for the hour before bed.
– if you are up in the middle of the night, again have low lighting. Particularly troublesome in many homes are the bright bathroom lights, instead put a small night-light in the bathroom to use if need be.
– watch out for your neighbors too by turning off outside lights that aren’t truly needed, and if you need outdoor lights, aim them downward so you are not committing ‘light trespass.’ (Interestingly, Bogard cites studies showing that increased lighting does not decrease crime, that criminals like to work in a well-lit area just like everyone else!)

Be purposeful about making all of these lifestyle changes at the same time. Then notice after a week or two how your sleep has changed!

Reducing Night Nurse Fatigue

March 30, 2014

Lately it’s been a pleasure to provide an intervention program for night-shift nurses to help them sleep well during the day, and thereby improve their alertness at night. For many nurses working nights a typical shift is 12 hours, often from 7pm to 7:30am. This requires them to function well during the hours that human beings are designed for sleep. Many of these employees like to sleep during the night on a similar schedule to their loved ones when not working, which keeps them in a perpetual state of circadian misalignment, making it even more difficult to function well at night.

In December 2011 the Joint Commission issued Sentinel Event Alert #48 on the effect of extended work hours and cumulative work hours on patient safety and nurse health. They summarize the extensive research on the performance effects of working at night. Some of the results of fatigue include:
– impaired information processing and judgement
– inability to focus attention
– reduced motivation
– loss of empathy
Fatigue among healthcare workers increases the risk of adverse events, decreases patient safety, and negatively impacts the health of the night shift workers.

The Commission report goes on to suggest steps organizations take to improve employee alertness and thereby improve patient safety. Fatigue management typically includes steps for both individual employees and the administration. Sleep training for employees so they can sleep well during the day, and entrain their circadian rhythm to the schedule, is one step. Another is fatigue reducing strategies such as precisely-timed caffeine and light to increase alertness on the job. Administrations can optimize their scheduling practices, and provide an alerting work environment. You can see the full Sentinel Event Report of the Joint Commission here: http://www.jointcommission.org/sea_issue_48/

Over the next 6 months I hope to continue this work for Seattle-area hospitals, and expand to help other public safety organizations that are providing 24/7 service, including the police and fire departments. Around the clock service is a must for public safety, and helping these night-shift staff to sleep well during the day, so they can be alert and healthy during the night is extremely rewarding!

Top 10 Online Influencers Helping America Sleep Better

January 27, 2012

It was a good morning to open my inbox and see that I’ve been named one of ‘The Top 10 Online Influencers Helping America Sleep Better’ by SharecareNow.  See their announcement here  http://www.sharecare.com/static/sharecare-now-shift-work-sleep-disorder

There are some great resources among this list for people wanting healthy sleep and it’s many benefits. Here’s a run-down of the Top 10, with the links to their sites. Enjoy!

Meet Us at the Bus Stop

January 24, 2012

So . . . how many of you are driving to work at 6:30ish? Ever see a kid suddenly caught in your headlights as they are waiting for the bus?

Over the last months the Start School Later movement has been gathering steam as almost 3,000 people across the nation have signed the petition, and the media has discussed the research showing that students do better when school starts later.

This week, on Thursday January 26th, the Meet us at the Bus Stop event is happening across the country to highlight how early children have to get up for school, so early that they are often waiting in the dark, on cold winter mornings, to catch the bus. Please join in by posting photos or video interviews of your children as they are waiting for the bus on Thursday morming. You can post them on Facebook at https://www.facebook.com/events/279393105455960/

See video from the previous Winter Solstice 2011 event at http://www.youtube.com/watch?v=rl0zvs43wjQ&feature=youtu.be

Sign the Start School Later petition at http://signon.org/sign/promote-legislation-to.fb1?source=s.fb&r_by=1521139

Better School Start Times

December 31, 2011

Over the last several months national efforts to start school later have been growing, and it’s about time! For over 2 decades it’s been well established by medical research that there is a shift of the internal body clock during puberty. This causes teens to become sleepy later than younger children, and wake up later. This is a physiologic change, and not simply a preference for later socializing or “laziness” in the morning as was sometimes described.

Terra Snider, PhD, has created a national petition calling for legislation to prevent high schools from starting before 8am. When students go to school at times when they are most alert their performance improves, including improved test scores, decreased absenteeism, and increased graduation rates.

This issue is very close to my heart, and of utmost importance. Right out of college, in the early 1990’s, I worked in the research lab of Dr. Mary Carskadon, the leading researcher on children’s sleep/alertness patterns. After a couple years my impression was that a lot was known about this among researchers, but wasn’t being used to make children’s lives better. So although I’m interested in research, I decided to become a physician and help people with sleep problems. Now in my private practice it is striking how many adults say their sleep problems started as teens. For this reason I love to help children with sleep problems in hopes of improving their sleep before they’ve had problems for 20+ years.

Please sign this important petition, then ask your circle of friends to sign it too. http://signon.org/sign/promote-legislation-to.fb1?source=s.fb&r_by=1521139.   As of this writing there are 1466 signators across the nation, and growing each day.

There is a wonderful website by Dennis Nolan, JD, summarizing the impact of school start time on student’s well-being at http://schoolstarttime.org/.

If you are inspired to lend your talents to improving student’s lives in this way please let me know, or contact organizers directly.

Timing Light Therapy and Melatonin Supplements

October 28, 2010

It’s been fun to talk with people suffering from Delayed Sleep Phase over the last couple days.  There’s been some questions about shifting sleep phase using light therapy and melatonin supplements.  The timing of these therapies depends on whether you want to delay sleep, ie. make it begin later, or advance sleep, making it occur earlier.  Once you know that, then you use the Phase Response Curve to see when to use these therapies.

A word of warning:  The correct timing is crucial, so it is best to work with a sleep professional if you want to shift your sleep phase.  If you use light or melatonin therapy at the wrong time you can cause problems by shifting your circadian rhythm the wrong direction.

Follow this link to the Phase Response Curve on Wikipedia: http://en.wikipedia.org/wiki/File:PRC-Light%2BMel.png

On the horizontal axis you see time, and the sleep period written in.  On the vertical axis you see hours of phase advance on the top, and hours of phase delay on the bottom.  Bright light is represented by dark purple, melatonin by green.  Note that the light curve goes both higher and lower than the melatonin, that is because a much larger phase shift can be achieved with light.

Let’s look at an example.  Say an adult is unable to sleep until 2am, but must get up for work at 7am.  Getting 5 hours of sleep each night is not enought for her.  She would like to sleep from 11pm to 7am, but is just not sleepy.  Using the Phase Response Curve, she begins using light therapy each morning when she gets up for the day.  She also takes some melatonin 6 hours before bed.   These combined therapies allow her to feel sleepy at 11pm, and fall to sleep easily.  Now she can get a full night’s sleep, and all the benefits of sufficient sleep.

Are you an Owl or Lark?

October 25, 2010

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.


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