October 1st, 2010
08:40 AM ET
Every weekday, a CNNHealth expert doctor answers a viewer question. On Friday, it's Dr. Melina Jampolis, a physician nutrition specialist.
Question asked by Amy of Houston, Texas:
I am 39 years old and petite (5 feet and weigh about 94 pounds). My doctor recommended that I work out with weights to increase my bone density, since my small size puts me at greater risk for osteoporosis as I get older. How much weight is needed to strengthen my bones and are there certain types of exercises that would be most beneficial for this purpose?
Hi Amy - It is terrific that your doctor is taking such a proactive approach to your health. Prevention is definitely the best approach when it comes to osteoporosis, especially because the lifetime risk for women of an osteoporosis-related bone fracture is 30 to 40 percent.
A combination of weight training and weight-bearing cardiovascular exercise is important for stressing your muscles and bones, which helps to strengthen them and thereby decreases your risk for osteoporosis.
When it comes to weights, you should work all major muscle groups (back, chest, arms/shoulders, abdominal muscles, and legs/buttocks) at least twice a week. Aim for two sets of each exercise, eight to 12 repetitions per set.
Be sure to perform exercises in a controlled manner rather than using momentum and gravity to lift and lower the weights. The amount of weight you use should be challenging enough that your muscles feel tired by the end of the second set.
If you are new to weight training, you may want to hire a personal trainer to show you proper weight lifting form to prevent injury or use the machines to ensure that you use proper form.
For cardiovascular exercise, weight-bearing, higher-impact activities such as walking, jogging and aerobics are better than nonweight-bearing or lower-impact exercise such as swimming, cycling and elliptical machines, which put less strain on your muscles and bones. Aim for at least 30 minutes five days a week for osteoporosis prevention and optimal health.
And don't forget about diet. Getting adequate amounts of calcium (1,000 mg/day until you hit age 51, at which point you should increase to 1,200 mg/day) and vitamin D (400-1,000 IU per day) is essential.
Eating plenty of fruits and vegetables, especially deep green leafy vegetables rich in vitamin K, can also help. Make sure to eat plenty of high-quality, lean protein like fat-free dairy, egg whites, fish and skinless chicken (protein should make up about 20 percent of your total calories) and limit vitamin A fortified foods or multivitamins with high doses of vitamin A, which can negatively impact bone health.
Skip supplements like black cohosh, which do not seem to offer any added benefit to diet and exercise. Finally, don't smoke, and limit alcohol and coffee consumption (too much caffeine can impair the absorption of calcium) for a complete osteoporosis prevention program.
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