These Family-Friendly Outdoor Winter Activities Double As a Workout

Just feel that crisp air! Simply being cold triggers the body to burn extra calories-on a par with light exercise-to warm you up, explains Francesco Celi, M.D., a professor of medicine at Virginia Commonwealth University who has studied the subject. Add some activity and you really get the benefits: You burn 25 percent more calories stomping through the powder than walking on a flat surface. Plus, it's practically criminal to let winter go by without at least one snow day. (On the days you stay in, try these seven at-home workouts.) Here's how all that fun stacks up, according to exercise scientist Stephen Herrmann, Ph.D., an adjunct faculty member at Sanford Research in Sioux Falls, South Dakota.

Hiking through the snow

You use more leg power walking through snow than on a flat surface, which means more muscle fibers firmed. (We think taking a winter hike is the best way to enjoy the trails.) Calorie burn: 340 calories*

Sledding

Trudging uphill will give your glutes a workout, while keeping your balance on the downhill helps strengthen your core. Calorie burn: 450 calories

Cross-country skiing

This cardio is a nonstop compound movement of upper and lower body that will strengthen shoulders, arms, abs, butt, and legs. (First try these exercises that will prep you for winter sports.) Calorie burn: 435 calories

Snowball fight

Squatting, sprinting, lunging, and throwing. It's a complete workout, engaging the upper and lower body and core-no counting reps! Calorie burn: 370 calories

Building Mr. Frosty

It's all-around resistance work: You'll be shoveling, packing snow by hand, and likely holding static squats before you're done. Calorie burn: 340 calories

Ice skating at the rink

This workout is as much for your abs as your butt and legs, and you'll firm many stabilizing muscles you don't really tap when on solid footing. Calorie burn: 450 calories

*All calorie counts are per hour, based on a 140-pound woman.

Baby on Board

We asked a couple of winter sports pros what to do with toddlers in tow.

"With a good snowsuit, boots, hat, and mittens, we can do anything," says Olympic cross-country skier Kikkan Randall, mom to 2-year-old son Breck. "I bring Breck along in a baby carrier backpack for hikes or a Thule Chariot ($632; rei.com) [adapted with a Thule cross-country ski kit, ($300; rei.com)] for cross-country skiing, then let him get out and play."

For Brenna Huckaby, a Paralympic snowboarder with a 20-month-old daughter, Lilah, half the year is a snow day. "We are an outdoor family. I gave Lilah her own mini snowboard [when she could stand]," Huckaby says. "When she was 11 months old, she was already able to ride it down a bunny slope with me alongside her."