Is Your Circadian Rhythm Longer Than Average? Night Owl Versus Morning Person

Early in my nursing career, I was hired on night shift 7pm to 7am. The advantage was not having to find child care for my two young children, and the extra pay helped tremendously. I was able to send them off to school and sleep while they were there. The disadvantages for me outweighed the advantages; being woken up by noisy neighbors, never feeling fully awake,and feeling like I had a heavy blanket over my body.


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    Specializes in Gastrointestinal Nursing. Has 31 years experience.

Have you ever wondered why one person thrives on night shift while another can't stay awake and feels horrible? I have. Research shows that there may be personality traits, and genetic factors that contribute to a person being a night owl versus a morning person.

An article, "Night Owls and early birds have different personality traits," by Agata Blaszczak-Boxe suggests that being a night owl versus being a morning person can affect a person's well-being. Both groups studied by the University of Barcelona showed good qualities, but the night owls appeared to have more adverse difficulties.

I asked a couple of friends who I used to work nights with about their feelings regarding night shift and here is Susan's answer:

"I did nights at first because of my young children. But as they grew, I just stayed on nights because honestly I don't have to see management or be involved in the multiple rounds and questions asked of the day shift. I only worked weekends so I really did not see mangement." Sue worked 28 years on night shift and 13 on days.

Predominate qualities of the morning people were; persistence, resistance to fatigue, difficulties, and frustration. As a result there were lower levels of substance abuse and less depression.

Predominate qualities of night people were; impulsiveness, extravagance, and temperamental. They are not afraid to explore the unknown which can lead to exciting adventures. However, although they are more creative, they can be more susceptible to addictive and antisocial behavior, insomnia, even suicide.

Ana Adan is quoted as saying, "several studies have linked different circadian rhythm genes with the development of mood disorders, schizophrenia and drug consumption." Men who are night people were shown to be more at risk for mental disorders than their women counterpart.

Being a night person seems to fade as we grow older, possibly because of decrease in activity.

The article, "Nurses Are Talking About: Working the Night Shift," by Laura A. Stokowski, breaks down how nurses feel about working night shift.

Love nights 47% Hate nights 32% Undecided 21%

These numbers surprised me, probably due to my personal aversion to night shift. In the same article, nurses expressed reasons for liking night shift such as; more time with patients, less stress, and slower pace, even though they acknowledged constant fatigue and difficult schedules. These same nurses reported that as a young nurse, the night shift was great, but as they got older, it became less tolerable.

In a new study from April of this year in the article by Amanda Onion, "Are You A Night Owl? It May Be A Gene Mutation," that studied 70 people showed that those who suffered from delayed sleep disorder (DSPD) also carried the gene CRY1. These people have a delayed circadian rhythm and go to bed later, waking up later than the average. The reason that they believe this gene may drive the circadian clocks is because it was not present in the people who did not have DSPD. It has long been theorized that genetics play a role in our inner clocks, but this is the first real evidence.

The lead researcher, Alina Patke states that, "Carriers of the mutation have longer days than the planet gives them, so they are essentially playing catch-up for their entire lives." Our circadian rhythm dictates our daily lives. It tells us when to eat, when to sleep, and even regulates our body temperature. For all but 10% of the population, this is a 24 hour cycle, but for that small percentage, it is longer.

The CRY1 mutation is one "letter" different, and that causes the delayed sleep disorder. Patke pointed out that not everyone who is a night owl carries the gene mutation. There is a lot more to learn regarding our genes as they are related to our sleep/wake patterns.

Some of you have heard of 23andMe, a genetic identifier company very similar to Ancestry. 23andMe studied over 90,000 people and was able to glean 15 different versions of genes that are connected to a person being a late riser, or early riser. Their article, "This one factor may explain why you're a morning person or a night owl," by Tanya Lewis.

In this article, our circadian rhythm is called a chronotype. David Hinds, the main researcher in the genome-wide association study linking genes to a specific trait, used spit samples to do their research along with surveys filled out by the participants. Out of the 135,000 people who filled out the survey, 75.5% of the people fell into a category of either night owl or morning person.

"Of the 15 genetic variants the study found that were linked to being a morning person, seven of them were near genes that are known to play a role in circadian rhythm. And some of these genes were also near ones involved in sensing light from our eyes." I found this so fascinating, that they can be so detailed with our genetic code as to link them with functions of our body that tell us when to be awake or when to sleep.

As with the previous study, this one also found similar traits among the two groups. The night owls often suffered from insomnia and sleep apnea while the morning people less likely to need 8 hours of sleep, they sweat while sleeping, and more apt to sleep walk. Because a lot of this information comes from surveys, it is limited because of the self reporting aspect.

Ivah also gave me some insight into her life of night shift:

"Just in case you are unaware, night shift people are a couple of bubbles off of plumb. More than a little strange. On night shift you actually had time to get to know your patients and families (and we didn't have the clipboards breathing down our necks). Evenings were good when my children were still in elementary/middle school. Yep, I would say that I am pretty much a night person. Can't do all night (now) but most nights I am not in bed before 12:30 or 2am." Ivah spent 19 years on 12 hour night shift, 3 years on 3-11, and 1 year on day shift. She is now retired and is 75 years young.

While gathering information for this article, I ran across an article that caught my attention called, "Night Shifts may hinder body's ability to repair DNA damage," taken from an article published by BMJ. They looked at healthcare workers on the night shift and evaluated their urine for the hormone melatonin.

The researchers in this study had actually already finished a study of urine samples that had showed a lower level of the chemical 8-OH-dG, a "by-product of active DNA tissue repair," in day sleepers. They went back and studied the stored urine samples to further explore the idea that night shift workers would also have lower levels of melatonin. Their idea was backed up by the fact that there was lower levels of melatonin in the night shift workers than those who sleep at night.

Melatonin has been thought to help in the repair of DNA damage caused by oxygen free radicals by giving the genes a boost. Because of the limitations on the study, the participants were "mostly white, working in healthcare and of similar age," no concrete conclusions can be drawn. However, it is a step towards understanding our body and how our work and life habits affect our health.

There are many reasons why people chose to work on a night shift; child care, less management, financial, and it allows for a better relationship/crew of the patients. Thank you to Susan and Ivah that gave their input on working night shift, Ivah was my preceptor as a brand new nurse and I have never forgotten her wit and knowledge. She was a fantastic mentor and I appreciate her for guiding me through that difficult and exciting time. Susan was a co-worker during that same time and I have never laughed so much at work than with her. I can still vividly remember some of the subjects that left me on the floor in tears after laughing so hard. However, I do have to say that it is her fault that I gained 10 pounds that first year because of her wonderful cookies. She was a great nurse and I learned so much from watching her.

Tell us your thoughts about working nights versus days. Include how you feel physically and mentally so we can get a full picture of how it affects you.


Blaszczak-Boxe, Agata. "Night owls and early birds have different personality traits." 24 July, 2014. Web. 10 April, 2017.

Lewis, Tanya. "This one factor may explain why you're a morning person or a night owl." 2 Feb. 2016. Web. 10 April, 2017.

"Night shifts may hinder body's ability to repair DNA damage." 26 June, 2017. Web. 28 June, 2017.

Onion, Amanda. "Are You A Night Owl? It May Be A Gene Mutation." 7 April, 2017. 10 April, 2017.

Stokowski, Laura A. RN. "Nurses Are Talking About: Working the Night Shift." 11 Jan. 2013. Medscape. Web. 10 April, 2017.

Gastrointestinal Columnist

Brenda F. Johnson, BSN, RN Specialty: 25 years of experience in Gastrointestinal Nursing

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VivaLasViejas, ASN, RN

142 Articles; 9,981 Posts

Specializes in LTC, assisted living, med-surg, psych. Has 26 years experience.

I've always been a 1500-2300 kind of person. My circadian rhythm is weird that way. I like to sleep from around 0200-1000, and now that I'm retired I don't have to conform to a daytime routine. Yay me!

That said, I also liked the 2300-0700 schedule and worked it for years before the hospital changed to 12-hour shifts, until it stopped liking me around the time I turned 40. I had to switch to day shift and hated every minute of it because at no point in my life have I ever been a morning person. There was also the matter of dealing with too many suits, families, doctors, therapies, fresh post-ops etc. When I moved back to LTC, I worked swing shift and was perfectly content until I was laid off due to low census. Later when I went into management, days weren't as bad because I was nine-to-five. But I never really did get used to it, and on the weekends I'd revert back to staying up till the wee hours of the morning and sleeping late.

Specializes in Psychiatric RN & Retired Psychiatric CNA. Has 4 years experience.

"Predominate qualities of night people were; impulsiveness, extravagance, and temperamental. They are not afraid to explore the unknown which can lead to exciting adventures. However, although they are more creative, they can be more susceptible to addictive and antisocial behavior, insomnia, even suicide. "

Wow. As I sit here at 2:45 AM studying for my last pharmacology exam, I found myself saying yes to everything in this article about night owls. I was diagnosed with a mood disorder and I am very antisocial/ 100% introvert, amongst other criteria.

It's like everything is better at night. Even when I try to be a daytime person, my body quickly turns back to night. Naturally.

Good information. I will certainly research more. Thanks.


10 Posts

I'm work evening shift.Love it.Night shift is too much,morning shift is nightmare ,evenings are beautiful.


1 Post

I work a 12 hr night shift and I can totally relate to several of the things in this article. While I don't find myself impulsive or extravagant I do have issues with insomnia, anxiety, and depression. I've always been a night person and both my mom and sisters are more night people. I just could never get up and get moving so early in the morning and I definitely dislike the hustle and bustle of day shift! I much prefer the teamwork and camaraderie of night shift and the slightly slower pace with less management and interdisciplinary teams there. I've worked nights for 10 yrs and I do notice that it has gotten more difficult the last 2-3 yrs and I do feel that it takes a toll. I feel tired a lot but I much refer this than dealing with day shift! Curious now to know if I carry the gene and if my mom and sisters might have it since we all can easily stay up till 2 am, even when we don't have to. My dad...definitely not a night owl...

Anti-Social is not being shy and not wanting to be around people. It's people who do things that's not socially accepted, like take food off of other people's plate, hit their drink out of their hand, bully people for no reason...doing things to make people angry for the fun of it...usually people with other mental problems. Introvert and Anti-Social is not the same thing. Introvert usually rather not draw attention while Anti-Social people usually likes the attention even though it's negative. Be kind of scary to have a anti-social person as a nurse.

I'm a new nurse and orientating and I like the night shift because it's calmer and quieter. I'm not temperamental or impulsive. I'm pretty calm and I'm having to orientate the night shift and day shift...and I like the night shift better especially in a LTC unit...when your expected to hand out 30 plus residence medication, answer calls, talk to family, talk to other staff, make sure CNAs work is done and helping them when needed and get your documentation done which is sometimes 10 or more residence. As well as dealing with the residence needs. It's a lot and sad how under staff most LTC units are...

I always felt more focus at night and that's when I would do homework, study, clean, or whatever. Some of us are night owls while other's are morning birds.

Specializes in Psych. Has 2 years experience.

My son and I both (son is dx) have a Circadian Rhythm disorder. I work nights