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

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.

4 thoughts on “Are you an Owl or Lark?

  1. delayed2sleep

    All too many doctors write that shifting one’s circadian rhythm is just so easy. It may be for some, but not for all of us. Thanks for a correct, well-written and REALISTIC report on chronotypes!

    1. Dr. Catherine Darley

      Thanks for your comment, your blog looks like a good resource to keep in mind for future and to point patients to as they work to understand more.

  2. Erika Davis

    I have Delayed Sleep Phase Syndrome but was undiagnosed with it for many years. Rather I was diagnosed as having insomnia, excessive anxiety and/or depression for many years. It has been very helpful to actually understand and accept that I have DSDS! Wish I would have known sooner but then I did accomplish a lot but I was exhausted and my immunity was low for years. I did have breast cancer and I do not know if this had anything to do with me trying to make myself a square peg in a round hole.

    1. Dr. Catherine Darley

      Hi, Thanks for sharing your experience. Regularly in my office, people will come in with a diagnosis of chronic insomnia, which has been treated with pharmaceuticals. However, it turns out that they have delayed sleep phase. When we shift their body clock earlier using melatonin and light therapy, they feel sleepy at bedtime for the first time ever. They are able to fall asleep easily, sleep well, and have good energy throughout the day. Which is very gratifying all around!


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