Circadian Rhythms Part II— When Your Internal Rhythms Are Out-of-Sync

At the end of the first blog about circadian rhythms we concluded that in order to be healthy it was necessary:

  • To get a good night’s sleep
  • Sleep in the dark
  • Be up during the day
  • Be on a regular eating schedule—no later than 8:00 PM

Now let’s look more in depth at what can occur as a result of a daily schedule that does not fit the above description.  John Hogenesch, a geneticist at the University of Pennsylvania said, “Disconnecting from daily rhythm strikes the body at the most basic level: the cell.”¹ He made an amazing discovery, “Nearly half of all gene activity is timing-related.”²  “This means the circadian clock could be influencing most, if not all, of our physiology and many of our behaviors,”³ Hogenesch said.  His team found that the organs in our body do not work at a steady pace.  They have certain tasks during the day and some at night.  They also have a type of “rush hour” at dawn and dusk.

For most people to have normal rhythms it would mean a change of habit patterns and this is not easy.  “But if more people understood the potential long-term benefits to their mood, sleep quality, cardiovascular health, weight loss goals and mental sharpness they might make the effort.”⁴, said neuroscientist Christopher S. Colwell of the University of California, Los Angeles.

Here are some of the actual conditions that have been proven by research to be caused in part by disrupted circadian rhythms:


  • For years psychiatrists have made the connection that people with mood disorders, and especially depression, tend to have difficulty sleeping and other problems with their circadian rhythms.
  • “A recent analysis of 19 studies found that treating sleep apnea with CPAP devices significantly reduces symptoms of depression.” ⁵
  • Given all the research it is clear that lack of sleep, as well as interrupted sleep, is a significant cause of depression and other mood disorders.

Decreased alertness and difficulty with short-term memory:

  • The number of industrial accidents is highest between 2-4 AM.  At these hours of the morning experts say, “…people should not be doing anything that requires vigilance.”⁶
  • Studies show that emergency room doctors working the night shift have difficulty with short-term memory.
  • Research has shown that, “…the hippocampus, the part of the brain central to learning and memory, is highly sensitive to circadian disruption.”⁷
  • This information lends much credence to the old fashioned concept of going to bed at a reasonable hour, getting a good night’s sleep and having three balanced meals during the day.

The Heart:

  • Blood pressure decreases at night when we sleep in order to give the heart a rest.  This is a great reason to get to bed at a reasonable hour—how about 11 PM or earlier—and sleep 7 – 8 hours!

Alzheimer’s Disease:

  • According to research at the University of Rochester Medic al Center, in 2013, it was discovered that when a person has a good night’s sleep the space between brain cells increases.  This allows for a good flow of cerebrospinal fluid between the brain and the spine.  As a result waste products can be removed from the brain decreasing a person’s chances of developing Alzheimer’s disease.


  • In April of 2015 scientists at the University of Warwick in England tested 70 women who had all suffered multiple miscarriages.  All these women also had disrupted circadian rhythms.  This work suggested, “…that a misalignment of daily rhythms in the womb hampers the ability of the fertilized egg to implant.”⁸

Weight Gain/Increased Appetite/Diabetes

  • Multiple studies at various universities  have shown that when people get only about 4 hours of sleep, or have interrupted sleep and have lights on:
  1. Body temperature, hormone production and blood pressure no longer followed regular patterns.
  2. The hormone leptin, that tells us when we have eaten enough, decreased.
  3. The hormone ghrelin, an appetite stimulating hormone, increased.
  4. The ability to clear glucose from the blood decreased.

In consideration of this information, we can see that reduced amounts of sleep and imbalanced circadian rhythms, even for short periods of time, can lead to weight gain—possibly obesity in the long run.  Also blood sugar problems, including diabetes, can occur.  These conclusions are supported by more than 50 studies.

After reading these two blogs you may be relating to some of the symptoms and wondering if your own circadian rhythms (body clock) are “out-of- sync”.  If so, I encourage you to consider putting some of the recommendations I’ve made into place in your life.   I’ll also be giving more ideas for improved circadian rhythms in “Tips for Circadian Health”, Part III of this series.  As always, I’d be happy to answer your specific questions and help you get started on the road to better health.  Feel free to call me at 773/262-7611.



¹Out of Sync, by Emily Laber-Warren, “Scientific American Mind”, Sept/Oct 2015, p. 34

²Ibid, p. 34

³Ibid, p. 34

⁴Ibid, p. 39

Sleep on It, by Robert Stickgold, “Scientific American”, Oct 2015, p. 56

Out of Sync, p. 37

⁷Ibid, p. 37

⁸Ibid, p. 37