Human Brown Fat Research Group Turku

In certain Nordic countries like Denmark, Finland, Norway, and Sweden, a long-standing tradition from the early 20th century involves allowing babies to nap outdoors during cold weather. This custom is based on the belief that exposing infants to fresh air, even in freezing temperatures, can strengthen their immune systems and promote overall health. In the 1950s, some parents and institutions in the Soviet Union also embraced this practice. An illustration of this custom can be observed in a 1958 photograph taken in Moscow, depicting a line of infants peacefully sleeping outside in prams, bundled up with blankets and fur hats.