Young children have a higher proportion of brown and beige fat enabling them to generate heat without shivering, which decreases with age.

“Small children have a lot of brown fat and beige fat, in particular because very young children can't shiver. As we get older, the amount of beige and brown fat tends to either reduce or shrink or disappear entirely.”

“As we get older, the amount of beige and brown fat tends to either reduce or shrink or disappear entirely.”