Have you ever wondered why children don’t seem to feel the cold outside?
Well, scientists say there’s a reason why adults often freeze in sweaters and teenagers are happy in shorts — even in freezing conditions.
And it’s not just because they’re constantly jumping around.
Your secret? With more brown fat – specialized fat cells that generate heat and maintain the internal body temperature of 37°C (98.6°F).
Unlike white fat, which is abundant around the diaphragm, buttocks and chin, brown fat is invisible and compactly distributed in depth, especially around the shoulder blades, spine and kidneys.
It makes up nearly 5 percent of a newborn’s body fat, but gradually decreases with age, making adults more vulnerable to colder temperatures.
Brown fat gets its color from being filled with iron-rich mitochondria, the cell’s powerhouses. Unlike white fat, which is an energy reserve, brown fat uses its power in the mitochondria to burn its own energy. When this fat burns, it can generate heat without shivering, which is called thermogenesis. As can be seen in the image above, babies have more brown fat than adults
In addition to dressing warmly in winter, our bodies also have their own ways of staying warm. Adults shiver and brown fat also helps generate heat. But young children have more brown fat than adults, which may be why they look warm even in winter
Brown fat gets its color from full mitochondria, the cell’s iron-rich powerhouses.
Its counterpart, the white variety, serves as an energy reserve for the body’s organs.
But when the body is exposed to cold, starting at around 16°C, brown fat is activated – starting the engine to generate heat in a scientific process called thermogenesis.
It does this by burning extra calories, breaking down blood sugar and fat molecules floating around the body.
And that’s exactly why experts think it could be a secret weapon for hitting the bump.
Dr Dayn Sellayah, an expert in cellular and organic metabolism at the University of Reading, told MailOnline it’s all down to a unique protein found in brown fat.
By uncoupling protein 1, as it is scientifically known, brown fat is able to break down glucose and fat molecules to generate heat.
And where it is in the body — including the neck, shoulders, upper arms, spine and stomach — means it intersects with blood vessels that can heat the blood pumped by the heart through the body.
While adults rely on shivering—when muscles contract rapidly to generate heat and keep the body warm—babies don’t develop this mechanism until they’re six months old.
This means they rely more on brown fat to stay warm.
And levels only begin to drop in adulthood, which may explain why adolescents appear to be less susceptible to the cold.
Dr. Sellayah said: “Babies and young children have large amounts of brown fat.
“This is especially necessary in the immediate postpartum period when newborns experience a sudden negative temperature gradient from the womb to the ward.
“Babies also cannot use shivering as a defense against cold.”
Women also have slightly more than men.
But it’s not just brown fat that keeps us warm.
The more white fat adults have — the fat that builds up when you eat more calories than you burn — the less likely they are to be cold.
According to Professor Kieran Clarke, an expert in physiological biochemistry at Oxford University, even white fat has some mitochondria that produce heat.
He also thinks that “skinny children are still cold”.
Thinner people generally have more brown fat than heavier people, according to a 2009 study in the New England Journal of Medicine.
Adults can increase their brown fat percentage by exposing themselves to the cold, say some experts in the field.
As you expose yourself to increasingly cold temperatures, stem cells, which can turn into many different cell types, can create brown fat cells instead of white fat.
At least that’s according to a study published in the journal Scientific Reports in 2018.
Crystal Leahy is an author and health journalist who writes for The Fashion Vibes. With a background in health and wellness, Crystal has a passion for helping people live their best lives through healthy habits and lifestyles.