An Australian who is living in Norway has gone viral after sharing a video of roughly a dozen babies sleeping outside in their strollers in freezing temperatures.

Olly Bowman, 22, from Sydney, has more than 200,000 followers on TikTok, where he documents his life abroad using the handle @mrmelk_.

The expat stunned viewers — particularly Americans — when he posted footage of himself walking by the unaccompanied infants who were peacefully napping outside in the middle of February.

‘It helps with their breathing and makes them more independent,’ he added of the supposed benefits. ‘It’s actually why so many people leave home earlier in Norway than other countries.’

Letting babies nap outside in the winter is a common practice in Nordic countries that dates back nearly 100 years — after a tuberculosis epidemic that swept through Iceland in the early 20th century was exacerbated by poorly ventilated housing.

In 1926, Icelandic doctor David Thorsteinsson published a pedagogy book that argued parents should let their children sleep outside in their strollers to get fresh air, even in cold weather, to strengthen their immune systems.

The tradition has been passed down from generation to generation, and it is common to see strollers with sleeping babies parked outside houses, apartments, and even local businesses in countries such as Norway, Denmark, and Iceland.

A 2008 Finnish study found that children ‘took longer naps outdoors compared with naps taken indoors.’ However, there is a risk of hypothermia in the cold weather, and experts say it’s critical that children are bundled up properly when outside.

‘A baby’s temperature can drop four times faster than adults, and they can become hypothermic,’ Dr. Jennifer Shu, a pediatrician in Atlanta, Georgia, told Insider in 2020.

TikTok users who are familiar with the practice took to the comments section of Bowman’s video to tout the benefits of letting babies sleep outside.

‘My Norwegian neighbor convinced me to do this and my youngest [does] not get sick as often as my oldest,’ one mom shared.