Should babies sleep in daylight?
There is a trend to use blockout blinds and curtains to create darkness for daytime naps for babies. The idea is to mimic nighttime conditions to encourage sleep.
But is this a natural approach to supporting infant sleep? Let's look at the evidence.
Around the world and for thousands of years, parents have had to juggle the needs of infant sleep patterns with adult responsibilities. So we have a pretty good idea of how this looks. We also have the world of primate parenting to give us further insight into how babies naturally sleep.
Unlike other mammals who create nests or dens for their young, humans keep their babies physically close day and night. This gives them protection, warmth and immediate access to the breast when needed. We see this throughout the primate world and in traditional communities.
Babywearing has been used for thousands of years to hold babies against the body of their mother or an alloparent to enable them to safely sleep with the reassurance of body heat, sounds and movement. Babies are not taken to darkness to sleep alone in stillness.
In communities where cradle boards and cradles were developed, these were used on or near the mother or caregiver. Generally created by communities living in cold climates, these tools were a way to share the warmth of a body or fireplace with a baby using insulation. But babies were never left alone to sleep.
Cradleboards are traditionally used by nomadic societies living in colder climates
Body clocks and babies
During pregnancy, the foetus relies on the maternal circadian rhythm to regulate sleep and wake times. But after birth, it takes around three months for the infant to begin developing their own body clock. This leaves babies with no recognition of day and night, no hormonal response to sunrise and sunset and an unlimited sleep/wake system. They simply eat and sleep, with brief periods of being awake in-between. As the infant begins to develop an independent circadian rhythm, their brain will react to changes in daylight. As the sun rises and our body clock senses an increase in light, our levels of cortisol rise naturally to stimulate our body to wake and go about daily activities. And as the day comes to an end and the sun goes down, decreasing daylight signals a time to increase melatonin release to calm our body and prepare for rest. This cycle continues throughout life to maintain the diurnal state in which humans live: active in daylight, resting in darkness.
Read more: Nighttime Breastmilk - how is it different
However, humans require sleep during the day and feed during the night throughout infancy (classified as the first three years of life). Both hunger and tiredness can override the circadian rhythm to allow for rest and nourishment day and night. So while the natural body clock becomes active after the newborn period, babies continue to follow a pattern of sleeping, waking, feeding, sleeping interspersed with periods of alert activity. Gradually the brain begins to consolidate the periods of short, frequent sleep into longer phases we commonly call “naps” during daytime and “sleep” during the night, although there is no natural distinction between the two.
Baby carriers allow infants to nap in daylight while carers go about their work
It is important to support the natural development of the circadian rhythm. Until very recent history, all humans followed a natural pattern of waking with the sun and working until sunset. Artificial light in the form of candles and oil lamps permitted limited activity after dark but the invention of gas lamps and then electric lighting changed human behavior entirely. When lighting in the home became affordable and accessible to almost everyone, working hours could be extended into darkness and shift-working became a way of achieving productivity around the clock. Work hours could begin or end in darkness, with domestic and leisure activities pushed back into the evening or later.
The arrival of television bought perhaps the most significant change of the 20th century. Replacing fireplaces as the central focus in living spaces, adults and children began spending more time staring directly at bright light in the lead up to sleep time. Rather than a gentle wind down in dim light before bed, people increasingly moved from the couch in front of the TV to their bed. The advent of recorded television and movies in the form of VHS and DVD allowed more consumption of video media and more time in front of screens. By the time personal computers arrived in homes and workplaces, screen exposure already played a significant role on how households ran. Computers, games consoles and growing demand for content brought about the transition from analogue to digital in many aspects of life. And then the smart phone came along.
Today, adults and children are exposed to bright light emitted from screens throughout their day. While parents are often intentional about the amount of screen time their young children use and believe their infants have little or no screen exposure, the reality is that incidental screen exposure is all around us. We are bathed in blue light.
Parenting author Sarah Ockwell-Smith explains:
White and blue based lights (including the light emitted from TVs, smart phones, laptops and almost all forms of lighting used in the home – that means no more CBeebies bedtime hour!) inhibit the body’s secretion of melatonin by tricking the brain into believing it is still daylight.
Increasingly, children - like adults - are struggling to switch into sleep mode after exposure to blue light in the home in the lead-up to bed-time.
So its understandable that the idea of creating dark spaces for daytime sleep has taken off. As society has faced significant rates of insomnia, good sleep hygiene has been recommended for adults and children. These guidelines include:
Be consistent. Go to bed at the same time each night and get up at the same time each morning, including on the weekends
Make sure your bedroom is quiet, dark, relaxing, and at a comfortable temperature
Remove electronic devices, such as TVs, computers, and smart phones, from the bedroom
Avoid large meals, caffeine, and alcohol before bedtime
Get some exercise. Being physically active during the day can help you fall asleep more easily at night.
Following these guidelines can help adults and children improve sleep during the night and are worthwhile habits to embrace. But are they appropriate when applied to daytime sleep for babies and young children?
The role of daylight in infant sleep
Parents have always joked about the impact of wakeful babies on their own sleep quality. There is no doubt that being woken by a baby multiple times a night for multiple months on end is exhausting. Modern lifestyle demands are at odds with disrupted sleep - hence the industry which has grown around insomnia globally. We would literally do anything for a good night’s sleep. Night waking in infants is seen by many as a problem needing to be eliminated as soon as possible - the global market in sleep training is even greater than that for managing adult sleep problems.
However, the evidence is clear - no matter how unpalatable: babies and young children wake at night throughout the early years and they do so because human babies have done so for millennia. Not because they are broken and need training but because they are human.
The industry of sleep training is unregulated and new “sleep whisperers” come and go as they ride the wave of desperate parents seeking solutions. They create “methods” and detailed programs based on schedules and routines in the form of books or locked behind pay-walls online. Trends come and go and a current one fixates on daytime and nighttime environments for sleep. Perhaps derived from the sleep hygiene guidelines for adults, one focus is on creating a simulated nighttime experience for daytime sleep. Where previously parents were encouraged to let their baby sleep exposed to the normal background noise of their household, sleep training enforces a separate room, complete darkness and white noise to mask any sounds from beyond. A consistent temperature should be maintained. Only sleep in these conditions is valued as quality sleep and parents should aim for most sleep to occur at home, in the infants own bed on the ir own.
By contrast, safe sleep guidelines recommend: “Place your baby on its back to sleep, in a safe space with a firm flat mattress, in a room with you” So unless you want to spend hours every day sitting in a dark room trying not to disturb your sleeping baby, you are probably going to benefit from letting your baby sleep around the light and natural sounds of their home while you get tasks done close by. Just as humans have always done!
Scandinavian babies routinely sleep outdoors during the day in all weather
Myself as a baby in the 1960s, having my daily fresh air and sunlight
Pram covers and infant safety
A disturbing trend to enclose a baby sleeping in a pram or stroller with a muslin or other cloth has led to warnings for parents. The UK-based organisation The Lullaby Trust cautions:
Babies’ prams, travel systems and buggies should not be covered with blankets, cloths or any cover that prevents the air circulating. Covering a pram or buggy with a blanket could lead to overheating, which increases the chance of SIDS. Using a cover also creates a barrier between parent and baby, which is risky as parents won’t be able to see if their baby is having difficulties or monitor their temperature easily. We recommend attaching a clip-on sunshade or parasol to a pram or buggy and checking if baby is getting too hot by feeling their chest or the back of their neck. Keep babies out of direct sunlight as much as possible.
In Australia, the Red Nose organisation agree, adding:
A recent study by James Smallcombe from Sydney University published in the journal Ergonomics found that covering a pram on a hot day in Australia can raise the temperature inside a pram by almost four degrees celsius. The study also found that using a moist muslin cloth and a battery-operated fan dropped the heat in a pram by five degrees in hot weather.
Red Nose suggests that it is essential to keep the sun off your little one, but covering the pram with a dry blanket or wrap is not necessarily safe, so using a damp muslin cloth is a safer option, or you can consider an umbrella or other ways to keep the sun off your child.
If parents use a damp muslin wrap to cover the pram, Red Nose recommends that they check the wrap every 20 minutes and re-wet it, as needed, to prevent it from drying out.
Infants do not need to have light and stimulation blocked out to sleep indoors or outdoors. Products sold for this purpose are not evidence-based and may create an unsafe sleeping environment for babies. Keep your sleeping baby within view at all times.
