Adult sleep typically happens in cycles that last 90-110 minutes and include various stages of sleep, but really deep sleep typically happens only in the first couple cycles (the medieval “first sleep”). I argued in the previous part that discontinuous sleep isn’t necessarily bad sleep, but it does seem to be true that being pulled abruptly out of a deep sleep can leave you exhausted, even if you still manage to clock a full night in bed. (I’ve lost my citation here, but I’m pretty sure there’ve been studies.) Normally adults wake out of REM sleep, not deep sleep. So the goal isn’t to avoid all interruptions; it’s to avoid having your deep sleep interrupted.
Sleep’s cyclical nature means there are also times throughout the night when you’re sleeping more lightly and are easier to waken. How can you increase the likelihood that your sleep cycles will mesh with your baby’s?
Start Together. Although sleep cycles incorporate all the stages of sleep, the relative length of each stage differs from cycle to cycle. The deep sleep part of your sleep cycles is longer right after you go to bed than it will be later in the night. The same pattern starts to hold true for most babies as they get older, too, once you get past erratic newborn sleep (though sometimes babies have a short sleep cycle first before diving into their longer ones). When I find that I’m not getting enough rest otherwise, I go to bed when Littlest does, between 8 and 9 PM, so that we have our deepest, longest sleep at the same time. If she’s done with her first sleep at 12 AM, it’s better for me if I’m also done with my first sleep by then. I also figure that going to sleep together helps our sleep cycles mesh better throughout the night.
Does your baby’s longest sleep cycle happen at a consistent time? Can you take advantage of it?
Use the Power of Suggestion. When Rebecca was about a month old, I started waking up just before she woke to nurse. Not all the time, but when I did, it felt magical to be able to give her what she wanted before she even thought to ask for it. Mostly I credit my boobs, who were keeping track of how much Rebecca drank and telling me when it was time to nurse. My experience of waking up just before Rebecca isn’t unusual, and if it’s not already happening for you, you may be able to nudge it along by deliberately telling your brain you’ll be ready to wake up when it’s time for your baby to eat.
In my experience, sleep cycles respond flexibly to mental suggestion and some kinds of external stimuli. My brain moves out of deep sleep when it anticipates waking up, meaning that subsequent interruptions don’t impact me so negatively. For example, if I know I need to wake up in three hours, I say something to myself like, “Sleep now, three hours, and wake fully rested,” about a dozen times as I drift off to sleep. I’ve been doing this sort of thing for years. As long as I get woken up when I expect to wake and not too long before or after, I’m more likely to feel refreshed than if I don’t bother with it. Now, I don’t normally do this with my baby because her night wakings are too erratic, but I’ve heard of babies you could set a clock to.
Alternatively, since tiredness happens in your head, you may be able to persuade yourself to feel less tired just by repeating that you’re going to feel well-rested tomorrow. No guarantees, but I’m pretty sure that if I kept telling myself the opposite, that I was going to be tired all day, then my brain would find a way to keep that promise.
What assumptions and wishes are you already making when you go to sleep? Are they appropriate cues for how your night is likely to be structured?
Sleep Close Together. Waking up to a gradual stimulus, rather than something like an alarm or a screaming baby, can also help you wrap up a sleep cycle. Most people, including my baby, become more restless before they wake. If you’re sleeping near each other, your baby’s increasing movement can wake you up gradually, too.
The other advantage of sleeping relatively close together is that if I wake up as my baby does, I can usually start to soothe her back to sleep before she’s fully awake. If she wakes up enough to start crying, it takes her much longer to go down again. Mosko, Richard, and McKenna’s study shows that I’m not alone here: compared to cosleeping babies, solo-sleeping babies wake up more fully, for longer periods of time, and seem to be more alarmed upon waking, which means that their mothers engage in more intense soothing activities, like rocking or bouncing. Bedsharing infants could often be soothed by stroking and such without getting out of bed. As a result, cosleeping nursing mothers in the study woke more frequently than mothers who sleep without their babies and spent three times longer nursing them, but 94% of them reported getting enough sleep, compared to 80% of the non-cosleepers.
How does your baby normally wake up? Does s/he start groping for a breast in her sleep like mine does?
It’s also worth noting that your baby may be responding to your waking cues as much as you respond to his. According to James McKenna, bedsharing babies tend to wake to nurse at intervals matching adult sleep cycles. If that’s the case, positioning your baby so that she can sense changes in your wakefulness may be just as important to preventing ill-timed interruptions as tuning in to her is.
–On adult sleep patterns, look at “Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask). And this is a cool alarm clock app for the iphone. It takes advantage of the fact that people toss and turn more toward the end of a sleep cycle to wake them at the optimum time.
-The original academic version of Mosko, Richard, and McKenna’s1997 comparative study is here. McKenna has also written several popular press articles summarizing his research, and they’re archived on Dr. Momma’s blog: If you look at “The Science of Sharing Sleep” and scroll about a quarter of the way down, you’ll find a discussion of maternal sleep and the fact that cosleeping mothers reported feeling more rested despite waking up more frequently. “Bedsharing Still Useful” is where you can read about the synchronization of sleep cycles between mothers and babies, about half of the way down, and it also has a good discussion of cosleeping safety. Miranda Barone’s work used the same data set as Mosko, Richard, and McKenna, and she summarizes her analysis here, reprinted from Mothering. It’s a nice balance of science and readability, though focusing on babies more than parents.
It’s particularly interesting that McKenna’s research indicates that bedsharing babies tend to match adult sleep cycles, because babies are frequently described as having shorter sleep cycles than adults. You can read Parenting Science and Baby Care Advice for more about the science of baby sleep patterns. But that data was based on solo-sleeping babies. Does the length of a baby’s sleep cycle change when she has someone sleeping next to her? McKenna and other advocates of cosleeping say infants rely on physical cues from parents sleeping nearby to help regulate their own biological processes. I haven’t done the research to see if there are any more recent studies on infant sleep cycles, though. The other kink is that the babies in these links may be a couple weeks younger than McKenna’s(?).
-But what if you’re too worried about cosleeping safely to sleep soundly? In addition to “Bedsharing Still Useful,” you might want to look at this.