Are You A Lark or an Owl? How Genetics Influence Sleep.

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What would you trade for a good night’s sleep?

If the answer is your first-born child, you might have a problem.

Although I joke, there isn’t anything funny about sleep deprivation. It is linked to heart disease, obesity, dementia, diabetes, Alzheimer’s, metabolic syndrome, and cancer.  It is inflammatory, compromises the immune system, damages DNA, and leads to premature aging and a shorter life. 

It is a modern problem that contributes to just about every chronic disease and it isn’t taken seriously enough.  Even within the culture of the broken healthcare system, the importance of sleep is dismissed.

A resident intern’s 24-hour plus shifts are looked upon as a right of passage, a test of endurance, despite the damage it may be doing to their health, let alone the precarious place it puts patients in their care. 


Lack of judgment when sleep deprived is a matter of physiology, not a matter of intelligence or dedication.


Practitioners who join my Nutritional Endocrinology Practitioner Training (NEPT) program are sometimes surprised at how seriously I take sleep and self-care, but to me, it’s truly a choice between optimal health or lifelong illness. Proper sleep is the foundation upon which a healthy life is built.

It’s nearly impossible for a healthcare practitioner to provide outstanding care when their own health is suffering.  This is one reason why everyone in NEPT has access to my Empowered Self-Care Lab. Self-care must come first and sleep needs to be seen as a priority, not a weakness.

Lifestyle plays an important role when it comes to getting adequate sleep, but what about genetics? Can a person be predisposed to sleep disorders or genetically able to get away with less sleep?

It turns out the amount of rest a person needs to sustain optimal physical and mental performance may be up to 80% genetic.

Science is just starting to unravel the genetics of sleep.


The Master Clock and Circadian Rhythms

Circadian rhythms are physical, mental, and behavioral changes that follow a 24-hour cycle.  Although the sleep/wake cycle is what most people associate with circadian rhythm, nearly every cell, tissue, and organ in the body contains a biological clock. 

The ability for body systems to function at their best is dependent on this cellular activity being synchronized. This job is left to the body’s master clock, a group of about 20,000 nerve cells that form a structure called the suprachiasmatic nucleus (SCN).

Located in the hypothalamus, it is up to the SCN to coordinate all internal clocks which regulate functions such as hormone release, eating habits, digestion, body temperature, and metabolism.



In general, a person’s internal clock is set to a 24-hour cycle, however, circadian rhythms vary from person to person. And the speed of that internal clock helps determine a person’s chronotype.

40% of the population has a circadian clock that tends to run faster than 24 hours. Typically this would result in a person feeling more alert, awake, and ready to do their best work in the morning, making them a “lark.” 30% of the population feels more productive at night which makes them an “owl.” The remaining 30% are in-between, but tend to lean towards the evening as being their most active time.

Although factors such as age, environment, and lifestyle can influence a chronotype, genes and gene variants play an important role in determining how fast your internal clock ticks and whether you are a lark or an owl.


The Genetics of Circadian Rhythms

Circadian rhythms are regulated by gene transcription and repression as well as by proteins that modify chromatin. In other words, they are controlled by gene expression.

Some of the most important genes in this process are the Period (Per) and Cryptochrome (Cry) genes. They code for proteins that build up in the cell’s nucleus at night then break down during the day.  Studies suggest these proteins help activate feelings of wakefulness, alertness, and sleepiness in addition to affecting how sharply the brain functions.

Environmental signals, such as light at different times of the day, can reset when the body turns those genes on, but when natural light-dark cycles are out of sync due to such things as time zone travel or shift work, it can alter circadian rhythms which can lead to sleep disorders. 

Light from electronics at night or gene mutations can also affect biological clocks and lead to chronic health conditions such as depression, bipolar disorder, and seasonal affective disorder in addition to those I mentioned earlier.


Sleep Genetics

Circadian rhythm has been researched extensively, but the study of sleep genetics is relatively new. 

Sleep is complicated and science wasn’t really thinking about sleep duration in genetic terms. Given the multitude of ways people alter natural sleep patterns (caffeine, pills, alarms) it was believed it would be impossible to determine whether or not there was a genetic connection.  


By comparing genes within families whose members demonstrated unusually short sleep patterns, a breakthrough was made.

In 2009 it was discovered that people who inherited a variant in a gene called DEC2 averaged only 6.25 hours of sleep per night compared to 8.06 hours averaged by those who didn’t carry the variant.  Then again in 2019, the same team lead by Ying-Hui Fu, PhD discovered a second variant in a gene known as ADRB1 that was associated with “natural short sleep.”

Natural short sleep is defined as “lifelong, nightly sleep that lasts just four to six hours yet leaves individuals feeling fully rested.”

What was especially interesting about the discovery is that though they sleep less, natural short sleepers don’t suffer from any of the adverse health effects associated with sleep deprivation. They also tend to be more optimistic, more energetic, and better multitaskers.  They seem to have a higher pain threshold, don’t suffer from jet lag, and may even live longer.

The exact reasons why natural short sleepers benefit from these gene variants has yet to be discovered. The hope is that by understanding why they experience better sleep quality and efficiency, science will gain a better understanding of the connection between good sleep and overall health.


As for the rest of us…….

It would be great if people such as myself, who find it challenging to get to bed on time, could attribute their owl tendencies to a beneficial gene variant, but the reality is they are extremely rare.

Given the demands of today’s world, it’s difficult for most people to determine what their natural sleep cycle would be.  Most of us need anywhere from seven to nine hours of sleep and have to be diligent with nighttime routines and sleep hygiene in order to get the sleep needed to support optimal health.

One thing that I strongly encourage both my Empowered Self-Care Lab members and Nutritional Endocrinology Practitioner Training (NEPT) students to do is take a “sleep vacation.”   A sleep vacation is basically three days in bed where you allow yourself complete rest, letting your biological clock determine when you will wake and fall asleep.

Not only does it help members reset to a healthy sleep/wake cycle, it’s remarkably rejuvenating.  Most people don’t realize how truly exhausted they are until they discover what it feels like to be thoroughly rested.

If you are interested in learning more about sleep, I highly recommend the book, Why We Sleep by Matthew Walker, PhD.


Sleep is not a sign of laziness.

Putting rest first does not mean you are a slacker. 

It’s time these old ideas were put to bed and sleep is recognized for what it is; the foundation of optimal health.  


  1. Circadian Rhythms
  2. After 10-Year Search, Scientists Find Second ‘Short Sleep’ Gene | UC San Francisco
  3. Circadian clock genes and the transcriptional architecture of the clock mechanism in: Journal of Molecular Endocrinology Volume 63 Issue 4 (2019)
  4. Genomics of circadian rhythms in health and disease | Genome Medicine | Full Text
  5. Circadian clock genes and the transcriptional architecture of the clock mechanism in: Journal of Molecular Endocrinology Volume 63 Issue 4 (2019)


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