Calkins prefers 15-minute dynamic warm-ups, followed by full range of motion stretching to protect against strain or sprain. Check out 4 Exercises to Warm Up and Cool Down.

For example, if you're a runner, a dynamic warm-up may include "a progression from walking to a very light jog, to some light lunges and finishing with stretching the hamstrings, quadriceps, hip flexors, glutes, low back, shoulders, chest and arms," Calkins says.

11. Keep drinking.
Hydration isn't just a hot-weather worry, it's imperative when staying fit in winter, too.

People often think they don't need to drink water unless it's hot outside, but it's still important in cold weather, Galloway says.

Sip water during your workout and switch to a sports drink, like Gatorade, if you're planning to exercise for 90 minutes or longer.

But, just like layering, don't overdo it. How much you gulp down isn't as important as what your body can absorb, Galloway says.

"About 3-4 ounces is all you can absorb at a time," he says.

So don't chug – sip. And don't save your hydrating to the last minute; drink regularly throughout the day.

Not sure how well-hydrated you are? Pillarella offers this tip: "Note the color and volume of your urine," she says. "Dark, low volume and infrequent urination indicate that you need more fluid."

Conversely, clear urine with high volume and frequency may mean you've had too much liquid.

12. Head into the wind – to start
The goal is to reduce wind chill during the second half of your workout, when you're sweaty and at higher risk for losing body heat.

The way you work out can make it feel colder too. "You create wind chill by your speed," Galloway says.

For example, running 10 mph into a 15-mph headwind creates a wind chill factor of 25 mph. On the flip side, running 10 mph with a 15-mph wind at your back reduces wind chill to 5 mph.

Of course, the faster you're moving, the higher the wind chill factor – and your risk for hypothermia. So if you're cycling or skiing, sledding or snowboarding downhill, dress in layers (see tip No.3).

^[1]