Should Humans Base Our Sleep Schedule on Daylight?

Biddy Box julyAs with most things in my life, it started with cats.

About a month ago, Biddy went on a wet-food diet. He loves wet food, and I’m pretty sure he would eat it non-stop if there were a machine that constantly fed him wet food. He wants that machine to be me.

Even though Biddy is far removed from his cat ancestors’ days of prowling the jungle for prey, those instincts still kick in around 6:00 am in the morning. So every day he sits on me at 6:00 am–2 hours before I normally wake up–and gnaws on my chin until I roll over and ignore him until 8:00.

Around the time this started happening, I read somewhere that human bodies are made to sleep when it’s dark outside. Thousands of years ago when we evolved into homo sapiens, it makes perfect sense that our bodies would shut down at night. Sure, we had fire to provide some light, but by far the best time to be awake was during the day, and at night there wasn’t much to do other than sleep.

I think the article might have been about why we shouldn’t keep our electronic devices near our beds, because the light from them tells our bodies not to fall into a deep sleep. Seems to me the same theory would work for daylight.

So the question I’m wondering is: Should we all be sleeping when it’s dark and waking just as the sun comes up? I doubt Biddy is the only domesticated creature on that schedule. Should we follow our pets’ leads?

Obviously I don’t want to go to bed at 8:00 when it gets dark and sleep until 6:00 am–I don’t think I could physically do that. But perhaps 10:00 to 6:00? Has anyone tried this, and if so, were the results positive? I’m trying to slowly work myself onto that schedule to see if I like it, but I’ve had a hard time falling asleep before midnight.

10 thoughts on “Should Humans Base Our Sleep Schedule on Daylight?”

  1. ” the sun has gone to bed and so must I”. That’s my goal every night but it never happens. I’m up no later than 4:45 which corresponds to when the sun starts to rise in the summer ( or at least turns the sky a shade lighter). I started this trend when I started running. I was too tired after work so I had to run before work. It took some time but now I wake up minutes before my alarm goes off even when I go to bed later than I want to ( like tonight). My dog definitely loves that schedule although she is very content to go back to sleep all day after our run. I do feel like I get a lot accomplished although by the end of the day I’m exhausted. It is also a very peaceful time- everyone around is sleeping or trying to wake up but the world isn’t crazy busy yet and I enjoy the calm before the chaos of my work day begins.

    Now off to bed I go. The sun disappeared
    Long ago.

    • Julie: That’s awesome! I was very curious to hear if anyone has attempted this. Perhaps the sun rises earlier than I thought… Other than the peaceful time it provides, does it feel more in sync with the natural rhythm? Do you feel healthier when you’re on that schedule?

      • I definitely feel healthier although that could be the exercising or a combination of the two. After a painful couple of weeks, it became easier to get up early. I think I am used to it since I often wake up minutes before my alarm goes off even if I’m up later than usual. I used to use sleep cycle alarm. It analyzes your sleep patterns and then wakes you up when you are in the lightest sleep ( within the wake up parameters you set). It also lets you know how many times you wake up and how deep of sleep you got. I stopped using it mainly because I was distracted by the phone and would stay up too late. Now it’s across the room so no distractions unless it’s a book I can’t put down which is a whole other problem.

        The sun gets up early but Arizona doesn’t do daylight savings so it’s an hour earlier for us. And Seattle is so far North that our summer days were so long (& then we paid for it during the winter).

        • Julie: Thanks for sharing this! I’ll keep trying it for a while to see if I see any results (especially since I don’t exercise in the morning 🙂 ).

  2. 10:00 to 6:00 schedule. That was my middle school years schedule and the best of my life. My middle school was close enough for me to walk to, so there were times I would take a stroll to school in order to deal with the chaos and puberty. As an adult, waking up at 6am to get ready for the 7am traffic is horrible! Then you have deal with traffic going home is soul sucking. I tried to go to bed at 10, but I feel like I need to watch some stuff to not feel so grumpy after dealing with the endless traffic and uncooperative people at work. So I don’t sleep until midnight and having a short sleep night equals more grumpy day the next day. Bad perpetual cycle.

    Anyway, I still think having your sleep hours from 10pm to 6am is great, especially when it’s a great night of deep sleep. No dreams, no night bathroom trips, nothing but sleep. I was told if I want a great sleep, I will need to turn off all electronics and be clear from them (like the next room) for 30 minutes or so. I guess with all the lights, beeps, and wifi signals, our sleep is disturb by them. I don’t have sources behind this, so if anyone know anything on this, please let us know. Thanks in advance!

    • Jasmin: Thanks for sharing that. It makes sense to me, as you say, that getting 7-8 hours of solid, uninterrupted sleep is the best way to go, and one of the ways to optimize that is sleeping when it’s naturally dark outside. I’m inching closer–last night I fell asleep at 11:30 and woke up at 7:00.

      • Have you ever researched sleep cycles or chronodisruption, Jamey? An average sleep cycle is 90 minutes (it can be a little more or less [80-100 minutes] and is unique to your body). So your 7 1/2 hours (11:30pm-7:00am) is probably a pretty healthy goal. I realized that my sleep cycle was almost exactly 90 minutes after a couple years in college, back when I had to pull some really late nights now and then. I could get by with 3 hours of sleep if I had to, but any less felt worthless. Likewise, I noticed after 4 1/2 hours or 6 hours of sleep, I felt much better than say, just 5 hours. Now, I always aim for 7 1/2 hours as a priority, 6 hours as a compromise, augmented with a 20-30 minute or 90 minute nap if I’m able to rest mid-day. And, as a result, I rarely feel groggy waking up or feel the need to supplement my day with caffeine.

        I don’t know how much the time of day plays into things, but it makes sense to me that if the majority of people over the course of human history didn’t have the luxury to stay up much later than dark through means of artificial light—whether you look through the lens of economics or technology—, that working with nature is a pretty safe bet health-wise.

        Chronodisruption, from the little I know, is tied to the idea of getting too little natural light during the day and too much artificial light at night, throwing off our bodies natural sleep rhythm, which can in turn affect other important aspects of our health. I’m (still) trying to train myself to spend intentional time outside during daylight hours… sit outside and read a little, eat lunch out on the deck, or play with my kids a little when the sun is shining.

        Since I work on my computer so much, I use flux, an app that changes your monitor temperature automatically based on your location and time of day. But I usually set it at a constant Kelvin temp that matches my need for accurate color settings for printed materials. Using flux has really reduced eye strain for me and seems to help me fall asleep quicker if I do have to work late at night. The color difference is quite jarring at first (especially if you play with the sliders), but I’d love to hear what you think after a couple of days if you decide to try it out.

        • Jason: This is fascinating! I hadn’t heard of the concept of chronodisruption (out of context I would have consumed it was a method of time travel). It makes sense: humans are made to soak up the sun during the day and relax/sleep when the sun goes away.

          I’ll think about giving the flux app a try. I’m a little worried about the jarring difference, but it is an interesting concept.

          • I definitely find it all fascinating—thanks for the opportunity to share!

            Ha, I was worried you’d be worried (because I was at first glance, too), so that’s why I gave you fair warning. But I think it’s jarring in a good way—you realize just how blue your screens are… all the time. The standard screen blue (at 6500K) is supposed to imitate daylight, and is an ideal temp for media (e.g. watching movies), which is probably why that’s the norm. I personally don’t like how low (orange) the flux app goes late at night, which is why I use a custom setting, apart from the reasons for my work. If you do feel inclined to give it a trial run, give 5500K a try. After an hour, put it back to 6500K, and if you’re not surprised at how glaringly bright and blue your screen looks and don’t instantly set it back to 5500K, you can get my money-back guarantee (the app is free). 🙂 I typically use 4500K, especially in darker lighting / late at night or 5500K if I happen to work in a very well-lit area.

            Best wishes on continuing to hit your health goals!


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