By Stephanie Stahl

PHILADELPHIA (CBS) — It’s a new kind of class promoting the idea of burning calories in the cold. You’ve heard of hot yoga, now we have a cold class.

The idea is that when your body has to work to regulate its temperature, you burn more calories and people have more endurance when it’s chilly.

Princess Sutherland is not a cold-weather person. But despite that, she’s trying something new — a workout class where the thermostat is set to a chilly 50 degrees.

“It was out of my comfort zone. I said ‘let me try this,'” Sutherland said.

It’s high intensity in low temperatures.

The class is called Brrrn, with an emphasis on the “brrr.”

The theory is that working out in the cold is more refreshing and can help you burn more calories.

“Our whole thesis is that we want you to sustain a higher intensity for a longer period of time and cooler temperatures do that for you,” said Jimmy Martin, co-founder of Brrrn.

Instructors say the frigid temperatures also trigger the body’s metabolism to keep you warm.

But you don’t have to have a class.

“You can go for what we call a ‘shiver walk,’ so like dress with light layers, go for a walk around your block, do some calisthenics,” Martin said.

After her first try, Sutherland says she’s convinced.

“It was just high intensity from the start. It felt better breathing in there and it just feels refreshed when you stopped working out,” she said.

It’s proof that you don’t need to be warm to work up a sweat.

Experts say exercising outside in cooler weather can also boost your mood and immunity during cold and flu season.

Stephanie Stahl