Decoding 3 pieces of sleep jargon: “active nightwakings”, “overtiredness” and “circadian rhythms"

Active nightwakings:

What we call “active nightwakings” (or “split nights”) are basically occasions when a baby wakes up at night and is not easily soothed back to sleep and wants to wake fully and play. These are different from the normal wakings that are a few seconds or minutes long, where a baby is easily soothed back to sleep through feeding or rocking or, when they are older, with a cuddle. Active nightwakings can be excruciatingly exhausting for parents and, on most occasions, do indicate an issue in the baby’s sleep that can be easily rectified. The second type of waking is a normal part of baby sleep. In fact, all human beings wake several times every night as all of us actually sleep in “cycles” where we transition from light sleep to deep sleep to REM sleep and then back to light sleep. We all wake in between each and every cycle but, as adults, we are able to roll over or pull up a blanket or fluff a pillow or snuggle our partner and fall back asleep, not even realizing that we are actually awake. Babies wake in quite the same way between sleep cycles but they are unable to fall back asleep on their own and need the help of a caregiver to drift back into a new sleep cycle. This is absolutely biologically normal. For breastfed babies, the easiest way to “bridge” sleep cycles is to simply nurse them. Otherwise babies can be bottle-fed or rocked or walked or, once they are older toddlers, patted or cuddled. The brief, non-active wakings are nothing to worry about and are part and parcel of baby sleep. They reduce organically n as babies grow older and develop the ability to connect sleep cycles on their own. There is absolutely no need for any kind of “sleep training” or development of “self-soothing” as the very idea is unscientific. It is akin to “training” our 6-month-olds to “walk” by repeatedly not picking them up. It makes no sense at their developmental stage. The best that we can do is have an age appropriate sleep routine throughout the day and ensure baby is not overtired and has a conducive sleep environment. These steps can go a long way in reducing wakings. The other type of waking – an “active nightwaking” – is different and can be much more exhausting for both babies and parents. After the age of 4 months, when a baby’s circadian rhythms have formed and baby has some concept of day and night, a baby will not usually wake to play at night. If she does, it means something is going on. One possibility is that the baby does not have an age appropriate sleep schedule – meaning, the right number and length of naps, optimum gaps between naps or a suitably early bedtime. Another is that the sleep environment is not conducive, like it isn’t pitch dark and quiet or the temperature is not comfortable. This can all be rectified with some effort and management on the parents’ part. The parent will need to learn about what routine is best for the baby’s current age and then help the baby into that routine by being sensitive to baby’s cues. It is also possible that baby is going through a specific phase like a “nap transition” (shifting from a higher number of naps to a lower number of naps per day) or a “sleep regression” (a temporary disturbance in sleep due to immense cognitive and physical development). In this case, not much can be done and we need to ride it out. It will pass in a few days or a couple of weeks. So, how exactly should we tackle an active nightwaking while it’s happening at night? When baby wakes up, continue to keep it dark. You can soothe baby with your voice and shush baby as you try to make her sleep again by feeding or rocking. If baby does not fall back asleep in about 20 minutes, you may need to throw in the towel and let baby play for a certain amount of time before once again soothing the baby back to sleep. Continuing to soothe an awake baby for over an hour can be extremely frustrating, to no avail. The next morning, though, it’s important to analyse what the reason for the active nightwaking could be in order to figure out how to deal with it.


When we stay awake past our optimum awake window, we are overtired. Think about a day when you’ve felt very tired around 10 pm, sat down to finish some work and then hit the sack around midnight, only to find that you’re feeling wired and awake now, tossing and turning, unable to fall asleep. When our bodies feel tired, they release a stress hormone called “cortisol” to wake us up. Babies are very sensitive to cortisol production. They have certain “awake windows” – spans of time that they can be awake at a certain age – before they need to sleep again, or risk cortisol production. These awake windows are determined by our “homeostatic rhythms”, which create sleep pressure and tell us when to fall asleep (something our “circadian rhythms” do as well, though only at night). Overtiredness is actually the bane of baby sleep. It is extremely important to help our babies fall asleep when we observe early sleep cues. If we miss these cues, our babies’ bodies will fill with the stress hormone, cortisol, and they will suddenly seem awake again – a second rush of energy that is called the “second wind” and that misleads us into thinking our babies are not ready to sleep. Soon, our babies and toddlers will become hyperactive and, eventually, cranky. If we wait till our babies are cranky to recognize that they need to sleep, we will find them to be fussy at the breast or bottle, and to need endless rocking and soothing to fall asleep. They will also wake frequently during the nap, take a short nap and likely wake up cranky. Crankiness is actually a late sleep cue and a sign of overtiredness. We have actually missed the boat in such cases. Now, the cortisol will also remain in the body and cause frequent nightwakings. So how do we avoid overtiredness? – By observing for early sleep cues (rubbing eyes and ears, pulling hair, looking glazed, not engaging, rooting – all for a few seconds) – By educating ourselves on and following age-appropriate awake windows and nap schedules – By bridging naps and morning sleep – By fitting the whole schedule with an early bedtime An overtired baby will neither nap well nor sleep well at night. In fact, an overtired baby is also unlikely to eat well or play well. It can be difficult to see our babies unhappy or under that kind of physical stress. Avoiding overtiredness can lead to a much smoother and happier day for the whole family!

Circadian Rhythms:

The approximately 24 hour cycle that runs our body processes in a timely, cyclical manner is called circadian rhythms. Almost all our bodily functions run according to a timer – whether it is the digestive system or the release of various hormones by our endocrine glands. The sleep-wake cycle is a part of this. How does this sleep-wake pattern work? Light enters the eye and is detected at the retina. Information is relayed to the suprachiasmatic nucleus, which is the central clock in the brain that sends messages to other parts of the brain and body to trigger a flurry of activity. Melatonin, cortisol, body temperature, movement, blood pressure, digestion, and consolidated sleep are all part of the circadian rhythm. When babies are born, they don’t have a developed circadian rhythm. While babies do receive the sleep hormone, melatonin, in the womb and from breastmilk, their day/night rhythm needs to form during their “fourth trimester” (just one of the many ways in which they complete their gestation outside the womb). The circadian rhythm normally forms between 2 and 3 months of age. A rhythm of cortisol develops at 8 weeks of age, melatonin and sleep efficiency develop at approximately 9 weeks, and body temperature rhythm at 11 weeks. Before this, babies often sleep at odd hours of the day and night. They do usually have a long stretch of sleep but it does not always align with our “night”. In the first 2 months, it does not make much difference if the baby is in light or darkness during the day or night. In month 3, however, it is important to keep baby in daylight from their morning wakeup until 6 pm, then to keep them in a dim environment until bedtime and then make it pitch dark when they sleep. If baby has started to get disturbed by light during daytime naps, it’s okay to keep it dim or dark for the naps and then keep baby in a lit environment while awake. Research has shown that thirty minutes of bright daylight in the first hour after wakeup can facilitate the setting of the circadian clock.