The Science of Sleep

Home » Family Life » Parenting » The Science of Sleep

Last week I discussed “Montessori” Approaches to Sleep and promised to follow-up with some more information about hormonal sleep windows. Hormonal sleep windows are important to understand not only for children, but for adults as well, as ignoring our bodies’ biological needs can have devastating consequences beyond having a hard time falling asleep. Even if your child has a great sleep routine now, its good to understand the basics of “sleep science” as their body’s rhythms and sleep needs will adjust and chance with time, and you want to be able to be one step ahead.

Sleep Science at Sugar, Spice and Glitter
Peasap – Sleep Like a Baby

Bedtime

A lot of people emphasize specific bedtimes for children, and stress that your child needs to have the same bedtime every night — I’m going to just go ahead and tell you, that’s completely unfounded. A child’s bedtime needs to be based on the sleep cycle that preceded it, so if your child’s nap fell earlier or later, or if they woke up earlier or later than usual (in the morning or from a nap), their bedtime needs to be adjusted accordingly.

But why is this?

Hormones


While our children are peacefully sleeping, seemingly at rest, there is a lot going on underneath the surface. Sleep is when all of our bodies grow, repair, and make new connections. If you’ve ever heard the phrase, “Sleep on it,” its not just because time gives perspective, but our brain makes additional connections between various memories (information) while we’re sleeping, so we are more likely to come up with “new” information, solutions, or ideas after we give our brains that chance to rejuvenate.

Deep sleep is also when growth hormones are released, which helps children’s bodies grow and repair. Deep sleep can only occur if the child is relaxed and not producing cortisol.

Cortisol is the “awake” hormone, and its activated by light. Melatonin is the “sleep” hormone, and its activated by darkness. Its so simple but perfect, but children’s bodies need time to adjust to the expectations of darkness, so using lowered or minimal lighting for the hour or so leading up to bedtime can help ease children’s bodies into sleep.

Routines

I stress how important bedtime routines are, and while “relaxing” activities are great, the main purpose is to create a chain of events that your child’s body identifies as culminating in sleep. I think its important to pay attention to your child with this and notice which activities are relaxing for them, and which just energize them all over again! For example, I can’t tell you how many people and blog posts have said that a bath and books before bed are their go-to routine — well, they don’t have my daughter.

Ella loves cold baths, which just awakens her nervous system, and gets really wrapped into the storyline of any story that we read before bed. Reading the same stories every night are a safe bet, but even better, I have two reusable sticker books that she explores until she can barely keep her eyes open.

Cortisol and the importance of a soothing sleep ritual are two reasons why I personally have never tried cry-it-out. A child who is upset and crying is going to be creating cortisol — and adrenaline — which is going to disturb his or her ability to get into deep sleep cycles; any form of emotional upset or stress will have a negative effect on sleep. There are many ways to encourage children to self-sooth without resorting to cry-it-out.

 Napping

I know a lot of people who think that they need to start cutting out naptime if their child is consistently having later bedtimes, when actually, naptime might just need to be adjusted in length or timing. Ironically, a difficult time falling asleep is usually linked to being overtired. In many cultures, naptime never ends — even grown-ups take part in the ritual, so there is no hard and fast rule about when naps should end.

Rather than looking at bedtime as an indication of whether or not the naps should be cut out, look at how your child behaves in the time leading up to naptime. Does their body naturally start to wind down? Do they exhibit whininess or overtired tendencies? If you’ve already tried skipping a nap, how did your child act during the naptime, or time after when it would normally have been?

Despite popular belief, children cannot “catch up on sleep.” So if a child stays up late for a special event, even if they sleep in the next morning, they are still operating on a sleep deficit. This is part of why it’s so important to protect bedtime and sleep routines. I had a really hard time with this when I had to work shifts that ended after Ella’s bedtime and my parents who were generously helping watch her, were not willing to watch her at my home and put her to bed. When I was able to work from home and put her to bed at an earlier time, I noticed a huge behavioural shift and Ella seemed to have a lot more energy than she did on our previous sleep schedule, despite getting the same amount of sleep.


I’ll follow up on this post with some ideas about how to set up an ideal sleep environment, and tools to help with bedtime, but for now, what are your sleep questions?

 

Similar Posts

19 Comments

  1. So many good points! I have found with my kids that for naps, there is a window of time that they will fall asleep. If I miss that window I have lost naps for that day. The hard part is when that window changes on a daily basis…

    1. I completely agree – there is definitely a window for sleep. In the early, newborn days with my daughter, I definitely stuck to a schedule. It helped me from going crazy as a new mom. Now I watch for her sleepy cues for naps and bed, and react accordingly. It’s basically at the same times every day, but I’m not watching the clock too carefully.

  2. Thank you for making the point that later bedtimes actually may be from being overtired! That is so true! My Little Bee actually sleeps longer if I put him to bed earlier and let him take a nap in the day time too! It is so important to watch for sleepy cues and act on them quickly to not miss that sacred window.

  3. My sleep question currently regards my 16 month old who seems to not be able to sleep independently all of a sudden. Would this be in regards to separation anxiety or a bit off schedule from travel (where she slept very well independently) or teething or something else that I’m missing? Just wondering if this might be normal and how long it might last for. We’ve approached it as we always have, just go sleep with her on her floor bed.
    Good sleep info in your post! Reading “Healthy Sleep Habits, Happy Child” really helped me have a greater understanding about sleep in general and respect for the sleep needs for different times of day and length of sleep.

    1. Its very normal at this age, and could just be a developmental stage or it could be a reaction to being off-schedule. I think you’re handling it perfectly, by meeting her “where she is” and being willing to give her what she’s asking for. If you don’t want to continue sleeping with her, or lying with her, you can slowly transition to patting her on the back while she falls asleep, conscious that you’re not falling asleep with her. It can be over in a couple of weeks, or a couple of months. Anything longer, it can just be her personality (I know I don’t like sleeping alone!) or if you are seeing anxiety in other areas of her life, I would address the anxiety issues and the sleep will sort itself out. Please let me know how it goes!

  4. My 2-year-old sleeps in a separate bedroom, should I stay there with him all the time he is trying to fall asleep or leave? He normally prefers me staying, but the process can take hours. What’s more, I feel like I am a larger stimulator for him, he gets distracted seeing me and punches, giggles etc.

    1. I think when you’re getting to two or three years old, it’s partially comfort and partially a control thing.
      They want control over the situation and your presence is comforting to them – BUT I would put a time limit on it and transition to leaving the room before they fall asleep. That way, they aren’t “pushing it” and you can also feel good about this bedtime routine. You will need to transition this eventually and you want to do it before you start resenting this bedtime routine taking up more and more of your night and limiting your ability to get other things done after bedtime.
      I would say, at the end of a routine that involves reading and some cuddles, lie down for 5 minutes – use a gentle indicator like a sandtimer or a phone set to gently buzz and give them a kiss and leave. Be firm and don’t change the rules/routine based on whining because it will never work!

  5. What about weaning from breastfeeding to sleep? I’m hoping to wean my son at 18 months. Tried at 16 months, but he cries too much for me. Want to wait until after the holidays now.

  6. Want to add that I’m Startng a routine of reading books in a dim bedroom on a bed on the floor. I cosleep with him. He just goes to the breast when he’s sleepy. He isn’t interested in a lovey replacement.

    1. I’m sorry for the delay in responding to your comment.
      This is a tricky one – they will resist that change, so it needs to be confidently replaced if you want to stop breastfeeding to sleep. (If you don’t want to stop, you don’t have to – but they aren’t just going to be “okay” with a change in routine like that)
      I would continue your routine – reading books on a bed on the floor, and ensure that you’re wearing a shirt that he can’t easily “access” your breast. Rub his back or make other physical comforting gestures to assure him that you’re there with him and that he’s safe. He may whimper or cry a bit for the first couple nights but it probably will be more “whining” than actual crying. If he uses a pacifier or anything, ensure that you offer it – but it doesn’t sound like he does.

      1. Hello! I have a 19mo old & she has never been the best napper/sleeper 🙁 We have finally gotten to the point where she is sleeping through the night consistently for 5 months now but her naps are still a nightmare…unless she’s sleeping on me. I’m intrigued to try her bed on the floor & let her roam around her room until she falls asleep but would hate to mess up her nighttime routine. For nap times she seems to need me to fall asleep, whereas for bedtime, we have our small routine & she’s asleep within minutes. She also can put herself back to sleep majority of the time at night if she does wake up. She sleeps better at night & is happier during the day when she does nap so I’m willing to let her nap on me if that’s what she ultimately needs but just being honest, I’d love to have that alone time to myself during the day. Do you have any recommendations for me to help her become a better napper?

        1. Hi Ashley, I’m so sorry I missed your comment.
          Every child is so different and habit has a lot to do with it. For my daughter, she did best with naps when she was allowed to nap in the same room that I would be in while she slept. Sometimes that would be on a couch or in her teeppe, sometimes we would use a portable travel cot.
          Please let me know how you ended up dealing with this sleep issue, again, I’m sorry for missing it!

  7. I have a 5 month old daughter and having a hard time getting her to take naps unless shes on top of me. While I love it and will do it as long as she needs me to i’d like to have her sleep on her own crib (tried floor bed but couldn’t keep dog off it at night since we live on a studio and got worried 80lb dog would crush or suffocate her >.<) Any ideas? I've read all your, and other bloggers, posts on sleeping that I could find. She also hates to go to sleep if she doesn't have boob even if she just ate 10 min before showing tiredness cues.

    1. Hi Bianca, I’m so sorry I missed your comment. I have it set up so that comments are supposed to send e-mail notifications to me, but it looks like this one was missed.
      I’d love to hear how you ended up making this work for you.

  8. Thank you so much for this article. I appreciate it so much as I struggle with what my heart says vs. what people say.. aka cry it out is not a thing for me. Thank you for explaining about cortisol and adrenaline. Makes perfect sense to me. As a Montessori guide/teacher in the classroom, I understand how important the environment is. I will need to make some changes to help my little one (and me) get some better sleep. Thank you!

  9. Struggle bus here.
    WFH mom. We have an au pair for M-F 8-5, but since my daughter turned about 1, her perfectly good sleep habits (floor bed) just went out the window. She’s 16 months now. There was a lot of things happening around 1, our last au pair ditched us (abandonment), she finally figured out scooting then very quickly walking, transition from two naps to one (or not??), and she has been getting her molars in. Needless to say she’s got a lot of milestones. I’ve always tried very hard to keep her routine in place for naps and bedtime. But she is at a point where she just will not go to sleep for me. The au pair can put her down and my mother and dadda, but she just stays up like she’s going to miss something. I try to let her get to that place by herself, but it just seems to take forever and she just gets crankier. So now she has the routine with me to just resist and be cranky which in my head is causing her trauma around sleep when related to me. I’m still breastfeeding and I’ve tried to put up some boundaries around that so she doesn’t get it all the time. It is part of our bedtime routine, but I don’t let her fall asleep on the boob. It’s been especially frustrating because I can’t put her to bed most nights. It’s crippling. If I try to just let her play in her room she just gets up and goes to the door and starts banging on it. So while I’m trying to facilitate a positive experience for slew and naps, I feel like I’m just creating a negative experience because I’m not willing to wait for her for three hours. Maybe that’s the key. I never did the cry it out method. I followed the sleep lady’s guide when sleep training initially, and she was doing really well until about 1. Even transitioned from a crib to floor bed around 6 months and she was faking asleep by herself with the floor bed. I’m trying to follow her lead, and I am ok with playing the ling game for mentally and physically healthy baby, but I’m at a loss for what I need to do now.

    1. Hi Ella,
      Sleep is hard, especially when you want to be a considerate and gentle parent.
      I don’t think you should worry about your daughter’s crankiness surrounding bedtime causing her trauma – think of it more like a bad habit.
      Do you have a sleep routine that you follow? Like reading for a few minutes, singing a goodnight song, etc? That may be helpful to get everyone who puts her to sleep to follow a similar routine so that those signals/cues help tell her body it’s time to sleep.
      If she’s just starting to learn to fall asleep with you without nursing, it will take a little while. For my daughter, she would be upset but I would rub her back and recite her favorite story to her to help her calm down. She had a very comforting routine that was exclusive to you and her and it’s going to take her a little bit to adjust to a new routine with you, but she will adjust if you stick with it.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.