Skipped the gym? Stand outside and shiver

Dr. Paul Lee examining a PET scan, showing deposits of brown fat around the necks of some patients. (Courtesy The Garvan Institute of Medical Research)

WASHINGTON – Turning your heat down a few degrees may do more than save you money on your power bill. It could also rev up your body’s calorie-burning potential.

Here’s the skinny on some new science:

A recent study conducted at the National Institutes of Health, and published in Cell Metabolism, suggests shivering can actually ignite calorie-burning capabilities.

This happens due to the conversion of regular fat cells (known as “white fat”) into “brown fat,” a type of fat that burns energy, rather than store it.

According to The Garvan Institute of Medical Research, around 50 grams of white fat stores more than 300 calories of energy, whereas the same amount of brown fat can burn up to 300 calories a day. When exposed to cold, white fat converts to brown fat in order to generate heat to keep the body warm and protect us from the cold.

The science of this conversion comes down to the body’s system of communication, as discovered by endocrinologist Dr. Paul Lee, the lead researcher on the study.

During exposure to cold (resulting in 10 to 15 minutes of shivering), fat and muscle communicate, causing a rise in hormones. These hormones then help to convert the white fat cells into brown fat cells.

In the study, Lee and his team exposed volunteers to increasing cold, from 18 to 12 degrees, until they began to shiver. Then, the researchers drew blood samples to measure hormone levels.

The research discovered that both irisin and FGF21 are released during shivering. The same amount of irisin produced from 10 to 15 minutes of shivering can also be produced from exercising for an hour on a bike, the study found.

Humans are born with brown fat around the neck — it’s designed to keep us warm as infants. It was previously thought that brown fat went away after childhood, but as reported by Dr. Oz on WTOP, we now know adults carry brown fat in the neck and upper back.

Research says adults with more brown fat are slimmer than those without.

One thing’s for sure: If winter keeps hitting hard in the Washington region, there will be plenty of opportunities for some shivering-induced fat converting.

But hopefully the cold weather won’t stick around for too long. Long-term cold exposure reduces shivering due to acclimation, the study says.

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