Should Babies Sleep Outside in the Cold?

The research behind the Scandinavian practice of letting babies nap outside

Source: Marcin Jozwiak/Pexels

IMPORTANT NOTE: Make sure you read the safety precautions at the end of this newsletter before trying this practice yourself.

In 1997, a Danish mother was arrested in New York City when she let her 14-month-old daughter sleep in a stroller outside of a restaurant on a chilly night while she and the child’s father enjoyed margaritas inside. She was arrested when other patrons of the restaurant called Child Protective Services and reported that the child had been left unattended. The mother insisted that she was simply following a common practice in Scandinavian countries in letting her child sleep outside alone. Yet, she was charged with child endangerment and authorities even temporarily took her daughter away from her. The charges were eventually dropped and she was reunited with her daughter— but this story highlights just how extreme this practice seems to those of us parents outside of the the Scandinavian region. More recently, a viral TikTok video brought further attention to this practice by showing all of the unattended strollers left outside of cafes and shops in the cold in Norway.

For those of us parents who live outside of Scandinavia, this practice of leaving your baby to nap unattended seems like some sort of Nordic mythology that we can’t even wrap our minds around. We might consider it an interesting cultural phenomenon but probably not something we would ever consider for our own children. That is, unless we thought it might improve our baby’s sleep. Recently I saw a reel on Instagram claiming that these outdoor naps might just accomplish this exact goal. This reel stated that: “Research shows that babies who nap outdoors in the cold could prolong their nap time by 400%”. This reel also claimed that napping in the cold is linked to improved temperature regulation and immune system functioning. It also mentioned that infants tend to be healthier in Scandinavian countries suggesting that this practice improves overall well-being. Whenever I see claims that “research shows” on Instagram that seem too good to be true, I can’t help but dig into the research to find out the truth about what the research actually indicates. This week’s newsletter will review the research on this topic to address the following:

• Is this really a common practice in Scandinavian countries and why?

• What is considered “too cold” for infants?

• Does napping outside actually prolong sleep?

• Are there any other benefits?

• Is this practice actually safe?

Is this a real phenomenon in Scandinavian countries?

It is true that many parents in Scandinavian countries leave their children to nap outside in the cold during the day. One study found that 95% of parents in Finland follow this practice. According to parent report, infants are usually placed in a stroller alone on the balcony or in the yard. However, they may even be left outside of cafes or shops alone while parents are inside. The infants are usually dressed in warm clothes and put in a sleeping bag. Parents usually start when the child is about 2 weeks old and stop around 1 to 2 years. Parents typically monitor their baby with a baby monitor or check on them frequently (such as every 15 minutes). In Norway, parents generally believe that it is safe to let their children sleep outside as long as the temperature is above −10°C (14°F), yet some mothers report letting their child sleep outside as long as it is above −20°C (−4 °F). Another study of parents in Finland found that most parents let their child sleep outside if it is above −15 °C (5°F) yet there was a wide range of temperatures that parents reported to be acceptable (see graph below). Most Scandinavian parents take napping outdoors for granted, in the same way other parents would take napping indoors for granted— it’s just “what you do.” In stark contrast. It is also important to note that this arrangement is reserved for daytime sleep and most parents in these countries practice bedsharing at night.

Most parents report that the coldest temperature in which they let their infant nap outdoors is−15 °C (5°F) or −10°C (14°F). Source: https://www.tandfonline.com/doi/pdf/10.3402/ijch.v67i2-3.18284

So why do Scandinavian parents put their babies outside to sleep for naps? Many parents report that they do it for the benefit of exposing their infant to “fresh air”. Other reasons include helping them to adapt to the cold climate, following a cultural norm or family routine, and instilling a love for nature

So does napping outside actually prolong sleep?

Unfortunately, there isn’t a lot of high-quality research on this topic. One study found that infants in Finland slept 92 minutes longer on average when sleeping outside than when sleeping inside (researchers compared the sleeping time outside versus inside for the same infant so it wouldn’t just be that parents are more likely to put infants outside when they are already sleeping well). When the infants were napping inside, they napped between 28 to 185 minutes; when they were napping outside, they napped from 83 to 300 minutes (so although the infants did nap longer— they did not nap 400% longer on average as claimed in the Instagram reel described above). The researchers also found that the infants who showed a more rapid cooling of their skin when sleeping outside slept for a shorter duration, suggesting that the sleep benefits only occur when the baby isn’t too cold. The researchers speculated that sleeping outside may be associated with longer sleep because it allows infants to be swaddled without overheating. However, this study is small and was not a true experimental study (meaning that there may have been other variables that differed between the inside and outside conditions) so further research is needed.

An earlier study using questionnaire data from parents in Finland also found that infants slept longer outside than inside, yet in this study parents only reported an average difference of about 34 minutes between sleeping outside versus inside.

Source: https://www.tandfonline.com/doi/pdf/10.3402/ijch.v67i2-3.18284

What about the other benefits?

Of course there is research that spending time outside is linked to positive health benefits in adults and older children but we don’t yet have any research showing long-term health benefits to infants sleeping outdoors. However, we do have some evidence that napping outside may help to limit the spread of respiratory illness in child care centers.

But won’t they get cold?

This practice of putting a 2-week-old baby outside to sleep seems shocking to parents in other parts of the world who worry about their baby’s temperature even on mild days. This worry makes sense since infants are actually more prone to hypothermia than adults due to a thinner layer of insulating fat and a poorly developed shivering response.

Research finds that the skin of infants that were exposed to lower outdoor temperatures cools at a faster rate, regardless of increased clothing. This finding suggests that parents may want to continue to monitor their children’s temperature when they are sleeping outside even when they are bundled up.

But is it safe?

It is very important to note that the safety of unattended sleeping in strollers outside has not been extensively studied and there is concern that it may increase the risk for SIDS. Parents should NOT attempt this practice without first talking to their pediatrician.

Research finds that sleeping in strollers is associated with an increased risk for sleep-related death (Both Sudden Infant Death Syndrome, SIDS, and accidental strangulation and suffocation). In particular, the straps and restraints in strollers may be dangerous when not used properly.

Older research also finds that colder temperatures are associated with increased SIDS risk, but this may be because infants are more likely to be put in excessive clothing and overbundled in colder temperatures. Other research finds that hotter temperatures and overheating are linked to increased SIDS risk.

There is also speculation that being outside may increase an infant’s exposure to air pollution since research finds that infants breathe in polluted air at a higher rate than adults and exposure to air pollution may increase rates of asthma and respiratory disease. Although, of course, the extent to which you worry about air pollution may be determined by the region you live in.

TRANSLATION

Putting your infant outside to nap is a very common cultural practice in Scandinavian countries. Although the research on this topic is limited, there is some research suggesting that it may be associated with longer naps. However, there may be serious safety concerns associated with this practice, including SIDS. If you choose to try this practice, you should always consult with your pediatrician first. If your pediatrician gives you the green light, then make sure that you use a stroller with a firm, flat surface and always monitor your baby. You may also want to check you baby’s temperature regularly and consider looking up the local air quality index (AQI) in your region (you can look it up at airnow.gov in the United States).

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Welcome to the Parenting Translator newsletter! I am Dr. Cara Goodwin, a licensed psychologist with a PhD in child psychology and mother to four children (currently a baby, 3-year-old, 6-year-old, and 8-year-old). I specialize in taking all of the research that is out there related to parenting and child development and turning it into information that is accurate, relevant, and useful for parents! I recently turned these efforts into a non-profit organization since I believe that all parents deserve access to unbiased and free information. This means that I am only here to help YOU as a parent so please send along any feedback, topic suggestions, or questions that you have! You can also find me on Instagram @parentingtranslator, on TikTok @parentingtranslator, and my website (www.parentingtranslator.org).

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