Understanding Sleep Stages


You probably remember learning in school about the two sleep states, non-REM sleep and REM (rapid eye movement).

Non-REM or deep sleep is the most restoring of the two and we have a regular heart rate and breathing and sleep quietly. In newborns, this is called "quiet sleep", although babies still have occasional body jerks (which may cause brief wakings, especially before 6 months of age) and make sucking motions. Around 2-3 months non-REM develops into
four stages: drowsiness, light sleep, deep sleep and even deeper sleep. Unlike adults, young children go through these stages very quickly meaning that they can be in deep sleep in just a matter of minutes. Non-REM sleep allows our body to recharge and is essential for a baby's healthy physical and mental growth.

*Gina Ford believes that the day time sleep problems (e.g. short naps) that many babies start to experience around 2-3 months are due in part to the newly developing sleep cycle which often leads babies to wake up after sleep transitions. This is especially true if baby is used to sleeping in a day time atmosphere or needs outside help to get to sleep (see sleep prop/associations).

Just before we reach deep sleep we often have a body jerk (also known as a hypnagogic startle) which is a normal occurrence but may awaken us. Signs that you have entered deep sleep include slowed, more shallow breathing and a relaxed body. Deep sleep is also sometimes accompanied by sweating and it is very difficult to wake someone up from. If there is an important stimulus it we will wake us up during this stage of sleep but we will be confused and have foggy thinking, although this won't be as pronounced as it would be if we were awaken at this time without an important stimulus.

REM or light sleep is where we dream (yep, maybe even newborns) and our metabolic and brain functions are very active. Breathing and heart rate are irregular but our body usually stays still since most impulses that are going to the muscles are blocked after a baby reaches 6-12 months of age. Before this time babies move around a lot and make sounds during this sleep phase which is why it is called "active sleep" in newborns. REM sleep is much more prominent in newborns taking up 50% of their sleep time (80% in a premature baby). It decreases to 25% by the time they reach preadolescence/adolescence. It is thought that REM sleep may be more prominent in babies so that they have more time to practice motor abilities, including breathing, during their sleep. It also may be more prominent to allow for more time to process daytime experiences and transfer things from short term to long term memory, though there is not firm evidence for this yet.

*A newborn enters REM sleep (light sleep) right away until approximately 3-4 months when he enters non-REM sleep first like an adult.

*We cycle between non-REM and REM while we sleep (usually have 1-2 periods of non-REM followed by a REM cycle) as well as have occasional, brief awakenings that most commonly follow non-REM cycles. When we have these awakenings we usually just go right back to sleep without even remembering waking up as long as everything seems normal to us. This is where many babies and children struggle if they are not capable of going to sleep on their own (always held to sleep, nursed to sleep etc). For more information on this see Sleep Props/Associations and Sleep Transitions.

*Adults usually spend the first few hours of night sleep in deep (non-rem) sleep followed by alternating periods of light and REM sleep with children usually having another period of deep sleep in the early a.m (see sleep transitions for more information on this).

13 comments :

  1. Rachel,

    My 8 week old (who was born 2 weeks early), has suddenly stopped napping well during the day and I am very confused. She is on a 3 hr PDF schedule, which moves to 2.5 hours starting at 5:30, and we put her down to sleep by 8:30, sometimes 9. We do not dream feed. She typically sleeps about 9-9.5 hours a night. She has suddenly started popping up early from naps, almost 30 mins before her next feed and is just content to lay there and look around. It's suddenly started to throw everything off schedule for the day, even if I am able to get her back on track. It's 2 days ongoing ( it started happening at the end of our vacation), so I'm hoping since we just arrived back home that she will go back to normal.

    Do you think she is ready for me to push out to 3.5 hour feelings? Or drop to 2.5 hr like baby wise suggests? What about her bedtime? I've been slowly trying to make it earlier and earlier, while extending her wake up times. It was 5am last week and I've been able to extend it this week to 6am. She used to eat for 30 mins, have about 20 mins of activity and then be just tired enough to put herself to sleep. Do you think I should try to extend wake times? Also, if she is waking up at 6am for a feed, should I count her next nap as a continuation of her night time sleep and just let her sleep or should I wake her up at the 3 hour mark?

    So sorry to ask sooo much!! I am just so confused and being a FTM with little support, I need all the help I can get! Thank you for the wonderful blog!

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  2. So I tried earlier bedtimes and now she is starting to wake up earlier and earlier!!!! Help! :(

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    1. I apologize that this took me a few days to get to nicolewynne. I'm still trying to catch up from all the holidays!

      If she's waking up early from naps contently I'd consider that she needs a slightly longer waketime before the nap. I doubt you need to move around tons more than that right now. Once her waketime gets longer, you'll naturally move to a 3.5 etc routine to adjust for that and adequate nap lengths. It could also be a developmental thing that'll pass shortly.

      Don't distress too much right now about the later bedtime. She's only 6 weeks adjusted and it is pretty darn normal to have babies go to bed a bit later in the evening at this age. At this age, I don't see a bedtime at this time being the main cause of early morning wake ups. I can't say it isn't for sure, just that it isn't my first guess. As her morning wake up moves later, you'll likely end up dropping one of her nap periods and have an earlier bedtime with that (does that make sense how that'll work?). Look over this post on early morning wake up times and eating
      http://www.mybabysleepguide.com/2009/06/morning-wake-time-importance-of.html
      I'd probably aim for something like 6:30 or 7 as your morning wake time. Maybe you'll be able to get it a bit later as she gets older, maybe not. But for now, start with the lower end of acceptable :) So if you are doing 6:30, then 6 would be waketime for the day. If you do 7, then I'd let her sleep until 7:30 about then start your day from there.
      Look over this post too if you haven't already:
      http://www.mybabysleepguide.com/2009/04/early-morning-awakenings.html

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    2. You'll find this under the link I gave you Nicolewynne, but try hard to treat those early morning wakings like part of the night. Try to get her to go to sleep in any means possible so she gets used to sleeping at this time. Use the swing etc. IF that doesn't work, then try to give minimal attention.

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  3. Rose, I just found this along with my answer in my emails. I don't know why neither went into the system. So sorry! I know it's too late, but I thought I'd post it anyway for others...


    Thanks for ur blogs! i know this should go with the other blogs like short naps or wake to sleep, but i decided to post here since there are no other posts =).

    we have a 4mo DD and is on a 3-hr EWS routine exclusively BF.
    (feed times are: 9am wake up,12,3,6,9 give and take 15-30 min.) falls asleep by 10:30pm after bath, story, song. (wake times are 1.5hrs give and take 15 min.)

    her naps are usually only 30-45min long. we have tried wake to sleep, but she usually just wakes up. we have tried CIO, but hasn't worked. so i pick her up and rock her with a paci and she will fall asleep right away if i don't let her cry for too long prior to PU. but as soon as i put her back down, she will cry again. do you think it's ok if i just hold her for the duration of her naptime since that works? i can also put her on the ergo and let her nap on me like that...? but i'm not sure if that makes me a sleep prop and will be a bad habit to break later...?

    it's tricky because if we don't let her nap the whole duration, then she will be awake for 45-60min before her next feeding and by then she will fall asleep on my breast. so we really need to get her full naps in. Unless you think I should go down to a 2.5hr routine? but she's already 4mo and should be on a 4hr routine, right? what should we do?

    as for her bedtime, we can put her down by 9:40pm but she will whine or cry till 10:30ish and fall asleep. and night wakings are b/w 1-2 (tho rare), b/w 3-4, and b/w 6/7. i BF her during all those and put her back to sleep. sometimes she will wake up by 8:15, sometimes closer to 9 (today for the 1st time, at 10am!! we didn't want to wake her up because we feel like she is so sleep deprived...averages 12hrs because of her short naps (not counting the feeding times at night) when she should be getting 15hrs!!

    if you think her bedtime is too late, can we just skip the last nap after the 6pm feeding and start the bedtime routine then? or is it such a sudden change and we should do it incrementally? if so, how do we do that? do i keep the 6pm feeding and still let her nap after the wake time and just slowly move the next feeding time by xx minutes (how much?) until it starts overlapping with the 6pm feeding?

    sorry this is loaded, but basically our question is how do we make her nap 1.5 hours and if we should have an earlier bedtime, how should we do it? thanks so much!!


    Rose,
    f you hold her entire nap period, either in your arms or ergo that very likely may turn into a sleep prop. BUT, if you can't get her to sleep more any other way and you aren't comfortable leaving her in her bed to either learn to sleep or just to rest and learn to be happy and relax and eventually fall asleep there (though it may take some time) then holding might be your best option right now. If you look at the extending nap post, I list some options in this situation.

    I wouldn't move back to 2.5 hours. That'll likely just introduce more issues. If you have to, do easaeas etc instead of easy.

    Don't worry too much about the feeding time in the evening. If you feed 2 hours apart because it works, then that is fine. I always feed before bed in young children too. Not to sleep, but before bed.

    A big jump forward in the bedtime hour may make her think bedtime is naptime. Some kids do fine though (won't know unless you try). Often going in right as they wake and helping them fall back asleep with any method (even feeding) can help them get through the habit of waking then. I'd probably do that method over shortening last nap until you get rid of it. Just put bedtime a little later than the last nap would have been, moving it a bit earlier with time if needed.

    Keep morning wake time the same. Take a look at the top sleep post and schedule posts for some pointers.

    Good luck!

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  5. Hi Rachel!
    I love your blog! It has been a huge source of information for me and I am on it throughout the day everyday lately...
    We just began sleep training on the 5th. We started off with PU/PD along with transferring her from the swing/vibrating bouncer to the crib. We've had success moving her to the crib (yay!) but PU/PD has been tough. And then I found your blog on last Thursday night and began implementing the wake-to-sleep for naps and my little lady's habitual night awakening at 0145-0345ish. It varies from night to night.
    My question is, I can't seem to nail the perfect time to do wake-to-sleep for the naps. Should this be done during the light sleep or deep sleep? If the first 10 minutes are light, and the next 20 min are deep, should I wake-to-sleep in last few minutes of the 20 min stage, or should it be done in the next couple minutes of the last 10 min stage before she stirs and awakens? I have been trying to hunt down this answer for days...if you could help me, that would be great!

    Thanks in advance, and don't you ever stop blogging :-)
    P.S. the night awakening hasn't resolved, but I've decided to work on one thing at a time, and that's the napping situation first...she's a miserably cranky/sleepy little lady that needs more sleep!

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    1. Averys Mom,
      Once she learns to go to sleep on her own, the night wakings and short naps may stop on their own. So make sure you are working on that aspect.

      Here's the post about wake to sleep
      http://www.mybabysleepguide.com/2009/02/wake-to-sleep.html

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    2. Thank you! I'll check it out again, although by now I probably have it memorized verbatim lol. We've gone back to PU/PD as of 145am last night...she has seriously regressed in the two days I've been doing shush/pat and having stopped feeding right before sleep. But I'll hang in there and keep up the wake-to-sleep.

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    3. Good luck! It's often a bit of trial and error, especially with the no-cry techniques. But that doesn't mean they won't work, it just may take a bit more time to figure out what works best for your baby.

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  6. Hi Rachel,
    my 3 mnth old is on 3hr EWS,but he cant continue a long nap on his own,he always wakes up durin sleep transitions,but he'll continue sleeping for another hr if i hold him,but if i put him in his crib again he'll wake up,
    i tried to shush pat him but most of the time i stay by his side for 20 min then he'll wake up again(probably returning from the rem to the non-rem),so what can i do to help him through his transitions without staying nearly 30 min by his side?how long should it take for him to make this transition on his own?

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  7. Hello Rachel. My four month old was easily able to take 1.5-2 hour lobg naps until right before he turned three months old. We have been battling the 45 min intruder for a month. It started with afternoon naps and has now worked to morning naps. Occasionally he will still take a normal nap, but this is becoming few and far between. We have been doing EWS routine since birth and he goes to sleep just fine on his own with no sleep probs for naps and night time. I have varied wake time length and nothing works. Because he has been such a good napper I never had to develop any type of soothing rituital. We briefly did CIO around 8 weeks to break the pacifier and since then he can put himself to sleep. He also still wakes once at night and I'm not always sure he is waking out of hunger or seeking comfort but the only thing I know to do to comfort him is to nurse (which I have never done to extend a nap). I've tried wake to sleep, placing a firm had on his chest, shush pay and pick up put down. Nothing seems to work. Today I picked him up after 10 min of shush pat, rocked him and gave him paci to see what would happen and he fell right to sleep. This is great but I don't want him to have a sleep prop again. Would this be a good method for extending naps since he knows how to fall asleep on his own? Any other suggestions? Also, we think he has been teething the past few weeks but naps were disturbed before this and I'm still trying to stick with a routine. He's on 3 hour routine for now but often doesn't seem hungry at the three hour mark. I'm hesitant to extend his routine because naps are so inconsistent and he's not STTN so I dont know if it would be wise to move to baby whispers suggested four month four hour routines? Thanks for your help! Love your blog!

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  8. Hi my son just turned 2 months yesterday on the 6th. I am trying my best to implement an e/w/s routine with him - trying to use a 3 hour but somehow we always fall apart by the middle of the day. I have a few questions.
    1. Can you provide some sample routines to follow for him - I exclusively pump so he gets just about all breast milk in bottles. Our wake up time has been 7 but I get confused on what to do in evening hours and bedtime

    2. He recently started sleeping a stretch of at least 5 hours from bedtime until about 1 or 2 am. We do a dream feed about 3 hours from the last time he ate before bed. He takes a pretty good feeding for this and it does seem to get him through till 1 or 2 am.

    Recently he started waking at 2:30 but is not interested in eating, he might take an ounce or two (basically snacks) and then wakes up again around 4/4:30 and does the same thing. Again he won't take a full feed and won't go back to sleep till about 5 or 5:30! Then we start our day at 7- it's getting very tiring

    Help!

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