Once you become a parent and your child starts a schedule of their own, they fall into a pretty predictable pattern.  You’ll hear people say they set their clock by their kids.  What most parents don’t know is that the pattern isn’t of the child’s own creation or desire, but rather the biological circadian rhythms at work.  And for those of us who have little ones who don’t nap or sleep well, working with these sleep cycles just may be the answer to resetting the biological clock and getting adequate sleep.

From Dalia Lorenzo, MD, instructor of neurology in the Sleep Disorders Center at the University of Miami Veterans Affairs Hospital…

Sleep is prompted by natural cycles of brain activity and consists of two basic states: rapid eye movement (REM) sleep and nonrapid eye movement sleep, which consists of stages 1 through 4. Each cycle lasts about 90 minutes, she explains. “You do that cycle several times night, you’ve had a good night’s sleep,” Lorenzo tells WebMD. “Anything that interrupts that pattern will cause sleepiness the next day.” … from Web MD

Graphicallly, here is what those sleep cycles look like.

Ps, this is why babies tend to wake more frequently after 3am, hint hint!

From Wikipedia

In humans, each sleep cycle lasts from 90 to 110 minutes on average,[10] and each stage may have a distinct physiological function.

The 90 minute sleep cycle is well documented in medical literature as well, like this study found on Pubmed.

These 90 minute patters hold true for awake time and sleep time for babies.  Your newborn may not follow this pattern until they are a few weeks old.  They may spend almost 90% of the day sleeping when they are first born.  As they grow, are exposed to sunlight and darkness, plus the rhythms of eating, they will develop these patterns.

In Polly Moore’s book, The 90 Minute Baby Sleep Program, she teaches parents how to recognize the sleep cycles, and to use this knowledge to get baby down for a nap easily.  According to her, babies from 1-4 months old, need to take about 4-6 45 or 90min naps a day (note 45min = 90min/2), and they should not be awake for more than an hour and a half (90minutes).

As that 90 minutes of awake time nears, the infant should show signs of tiredness, rubbing their eyes, yawning, or getting cranky.  With infants needing between 14 and 16 hours of daily sleep, newborns up to 18 hrs, allowing a child to nap on this schedule is critical for meeting their daily sleep needs.  Ignoring these signs of tiredness can be detrimental to developing the natural circadian rhythms, resulting in lost sleep, which has been documented to be very detrimental to our children.

Moore’s plan is relatively simple to implement.  She uses the acronym N.A.P.S for parents to easily follow.

N – Note time of waking

A – Add 90 minutes to that time

P – play, feed, whatever, enjoy!

S – Soothe to sleep just before the 90minute mark

Many babies my son’s age fell into this pattern on their own, and anytime I talk to my girlfriends about when naptime is, remember we have toddlers, they say XX:00, and in my brain I do the math, and its usually 3, 4 1/2 or 6 hours after wake up, all of which are multiples of the 90 minute cycle.  This cycle will hold true for the rest of their lives.

For babies though, that struggle with napping and sleeping for whatever reason, and their parents think that “my baby just doesn’t sleep”, using this knowledge can help you achieve those very much needed Zzzzzz’s. I remember when our son was a month old or so, and there was one day where he napped maybe 45 minutes all day.  Every time I tried to get him to nap, he just couldn’t fall asleep, no matter how much sling wearing or nursing I did.  He looked horrible, like some one beat him up, he was so tired, you could see he wanted to sleep and just couldn’t.  He had medical reasons then undiagnosed that were causing some of his nap inabilities, but we overcame that hurdle by following his sleep cycles.  When we started implementing this program, it took only a day for us to see an immediate difference.  Working with the sleep cycles , we went from horrible to happy.  At 3 months old, he was like any other baby with his nap schedule.

Also, parents need to remember that sleep begets sleep. This is counter intuitive to how we live as adults; if we nap too late, we can’t get to bed at our normal bedtime.  For babies though, every sleep expert and their books will tell you that adequate sleep during the day leads to more sleep at night.

Because we followed this NAPS program, we never had a set bedtime.   It was always and continues to be at 17 months, a multiple of 90 minutes from when he woke up from nap time.  We’ve tried having a set time of 8pm, but if you are trying to get a child to sleep in the peak of their cycle, its only going to lead to frustration.  Some parents may find this doesn’t work for their family, but for us, its easier to be flexible with bedtime than deal with a hyped up monster and force sleep.

So if wake up is 6:30am, nap will either start at 9:30, 11, or 12:30, either 3, 4 1/2 or 6 hours from waking.   We let him “tell” us how tired he is and decide based on that when nap is.  Then whenever wake up from nap is, we do the math again and get as close to 7-8pm for bedtime.

Beyond using the sleep cycles to determine nap and bed time, they also show up on their own every night in our son’s waking pattern.  He, at 6 months, woke every 45minutes throughout the night.  There was a medical reason for the waking, which you can read about in Our Story, but the timing was still controlled by his biological clock.  If you look at the diagram above, the transition from REM to the next stage is exactly where we see wakings.  At 17 months, he naps either for 90 minutes, 135 minutes or 180 minutes.  During the night, when he wakes, I look at the clock and only when he is sick or teething is the waking NOT divisible by 90 minutes.

This program can really help families struggling to get their little ones the sleep they so desperately need.  You can buy Moore’s book, but honestly, you don’t need to given what I have outlined above.

Happy Sleeping, Happy Napping!