It's easy to slack off on workouts during the coldest times of year, but you'll regret it once bikini season comes around in a few months. Stay on top of your fitness by choosing to work out outside at least one day a week. Revolutionary materials, like moisture-wicking fabrics, make it easy to stay warm and comfortable when you layer them. Bring something warm to sip that'll also keep you hydrated along the way - green tea offers flavor and a boost of energy if you choose to go caffeinated. A workout buddy can be essential to motivation at this time of year - when you're held accountable, it's harder to make excuses not to work out. Begin your workout inside by stretching your muscles.

Running up and down stairs or bouncing in place for a few minutes will get your heart going and make the cold more bearable when you do venture outside. If you live in a snowy climate, there's nothing better than cross-country skiing to burn a lot of calories in a little time. Snowshoeing and winter hiking are also challenging sports and can seem more like an adventure than a workout. Don't forget your summer workout essentials - sunscreen, chapstick and sunglasses. Above all, don't give up! If you just can't handle the cold, then find an indoor workout that you enjoy. Exploring the fitness DVD section of the video store could yield a new and exciting exercise opportunity!