Depending on resistance level and speed, mere-mortal non-Lance Armstrongs can burn up to 500 calories by biking for as little as 30 minutes. Even those living in cold climates can continue to cycle during winter. Most bike stores sell studded tires, perfect for cruising through snow. If you love bike riding, you’ll need to supplement your riding with strength training, particularly core-strengthening exercises to keep your muscles along the spine strong. With all that bending over, you’ll need it. Developing a strong core will also help you recruit your core muscles to pedal rather than just using your legs.