Yoga at home: Baron Baptiste is a great Vinyasa yoga instructor, and his books Journey Into Power ($12) and 40 Days to Personal Revolution ($12) offer heart-pumping sequences and pictures of correct alignment. If you stick to his regimen (each sequence is between 20-60 minutes), you'll enjoy a great yoga workout and may even master advanced poses that you never thought possible in a public class.
See more apartment cardio exercises!
Free StairMaster: If you have them, walk up and down the stairs of your building for 15-20 minutes. Be sure to keep your abs engaged and step up with your heel rather than your toes so you target the glut and hamstring muscles, or try doing two stairs at a time. Within five minutes you should feel the burn.
At-home weights: After completing a warm-up (either a few yoga Sun Salutations or five minutes of walking up stairs), complete a full-body circuit workout with weights. This full-body circuit combines exercises to work your arms while toning your legs, plus your abs and back will also be challenged.