Osteoporosis—when your bone mass becomes so low that you are at high risk for breaks and fractures--strikes 8 million women in the United States, according to the National Osteoporosis Foundation. Though the disease is most often diagnosed after menopause, women can start losing bone density as early as their 30s, says Lori Rubenstein, PT, CYT, a senior instructor at the Yoga Therapy Rx program at Loyola Marymount University.

But yoga poses that strengthen areas most likely to suffer—the hips, spine and wrists—can help maintain bone density to prevent bones from becoming dangerously fragile, she says. Poses that focus on the spine can also help improve posture, preventing the hunched back that is typical in older osteoporosis sufferers. Women who have small frames or family histories of osteoporosis are more prone to the disease—so if Mom or Grandma has been diagnosed, be doubly sure to add these poses from Rubenstein to your repertoire:
 
 
Chair Pose:
This pose strengthens the muscles around the hip, one of the most common sites for osteoporosis. It also works on your balance to decrease your chance of falling and fracturing a bone when you get older and your bone mass is decreasing more rapidly.
 
Start by standing in Mountain Pose with your feet hip distance apart. As you exhale, bend your knees to squat down (as if you are going to sit on a chair) while raising your arms overhead. Keep your feet flat on the floor with your knees aligned over your ankles. Your palms should be facing each other with your arms straight and shoulders dropped away from your ears. As you hold this pose, reach your tailbone toward the floor and your spine toward the sky. Inhale as you return to Mountain Pose. Hold for as many breaths as feels comfortable, but no more than six; repeat six times.
 
 
Cobra:
Osteoporosis patients often suffer thoracic spine compression fractures, where the front part of the vertebrae compresses down, causing a person's posture to look bent forward. This pose strengthens the upper back muscles and the spine, which helps keep posture upright and may help prevent a compression fracture from occurring. It’s also a perfect pose to prevent computer hunch.
 
Begin lying on your stomach with your legs slightly wider than hip distance apart. Place your palms on the mat next to your ribcage, fingers forward just under the shoulders. Keep your elbows close to your body as you draw your shoulder blades together and down your back towards your waist. You should feel an opening in your chest. On an inhale raise your head and chest off of the floor. This lift should come from your back, not your arms. For more of a challenge, lift your hands off the mat, holding yourself off the floor with the strength of your back alone. Keep your neck long and in alignment with your spine by looking at the ground a few feet in front of you. Exhale as you lower to the starting position. Hold for one breath; repeat 10 times.