If you live in a snowy region, give your exercise program a boost by trying cross-country skiing or snowshoeing. In terms of all-around aerobic benefits, they're among the best.
Cross-country skiing gives the muscles in the shoulders, back, chest, abdomen, buttocks and legs a good workout. It spares your body the impact that you get from running or other types of aerobic exercise. And, it burns 600 to 900 calories/hour.
Moving on snowshoes through the resistance that snow creates makes your body expend more energy, even though you're moving at a fairly slow pace. It also helps build up endurance and leg strength while offering good cardiovascular conditioning.
Both of these also give you a sense of peace and tranquility that comes from being out in Mother Nature's splendor at its finest.
Source: University of California, Berkeley. Wellness Made Easy. 1999.