In addition to helping you lose fat, build muscle, boost mood, improve sleep and so much more, weight training also helps improve bone density. Bone strength is intimately tied to independence, as hip fractures are the #1 reason for nursing home admissions. If you needed another reason to lift weights, here it is.
Bone density (or more specifically, “bone mineral density,” or BMD) is most commonly measured using a DEXA scan, which is like an x-ray. Although measurements at the wrist or other body parts may be added, the basis of bone health is diagnosed through bone density in the spine and hip. When you get a DEXA scan, your numbers are compared to what is considered “normal.” Osteopenia is mildly reduced bone density. Osteoporosis is more severely reduced density. Risk of breaking a bone increases the lower your bone density is.
Who Is At Risk For Low Bone Density?
Post-menopausal, thin women have the highest rates of osteoporosis. Estrogen is a potent bone-builder and the decrease in estrogen when periods stop increases risk. Additionally, men with low testosterone are at risk. Testosterone not only has direct positive effects on bone density, but also acts indirectly through its conversion to estrogen. People taking steroids such as prednisone or cortisone are also at elevated risk.
All of that being said, even if you are not in a high risk group, strengthening bones should be a priority, as the more dense you can make your bones, the more you can lose over time without suffering negative consequences. This is especially true for younger women, who will eventually become post-menopausal women.
Research Supports Weight Training & Bone Density Increase
In my review of the scientific literature as I was writing this article, I came across some surprising studies. One of these was published in the Journal of Clinical Endocrinology & Metabolism and actually concluded weight training decreased bone mineral density in the subjects, who were premenopausal women.1 Fortunately, these were the exceptions rather than the rule, and the vast majority of research supports resistance training as a very effective means to increase bone density.2 (Still, I found those papers interesting and thought they were worth mentioning.)
Scientists from Tufts University, in a published paper3, said “over the past 10 years, nearly two dozen cross-sectional and longitudinal studies have shown a direct and positive relationship between the effects of resistance training and bone density. They also acknowledged that some studies do not support this relationship. However, study design and the specifics of the exercise may have influenced the results (and most likely did).
Another paper concluded that weight bearing exercise before puberty protected against osteoporosis later on by increasing peak bone mineral density.4
The list of supporting research goes on and on, and there are benefits of exercise beyond those which you can get from medicine or supplements.5 The degree of improvement in bone density varied with the study, but in the real-world, it doesn’t matter. It is enough to know that weight training increases bone density, which gives you one more reason to do what you absolutely should be doing anyway.
How Can You Increase Your Bone Density?
In addition to taking calcium, vitamin D and other bone support micronutrients, not smoking, possibly taking medication (very controversial6) and addressing medical and hormonal issues that may be predisposing you to osteopenia or osteoporosis, weight bearing exercise and resistance training are crucial. Not only can weight training increase bone density, it can improve muscle mass, balance and connective tissue strength, all of which decrease risk of falling and breaking something (which in an older person, often signifies the beginning of the end).
Here are three exercises that are particularly helpful for increasing bone density in the hips and spine:
- Squats – You can do squats in many different ways, from holding a dumbbell in front of your chest (Goblet Squat), to using an exercise ball against a wall, to doing a traditional barbell back squat.
- Lunges – Forward lunges, reverse lunges, side lunges, and other types of lunges that require you to engage your hip and leg musculature while balancing on one leg can help improve bone density, especially when weight is added. You can add weight using a barbell, dumbbell, or weighted vest.
- Step Ups – Similar to a lunge, a step up requires a single leg to propel your body weight in the air. You can use a bench, a chair, or a proper stepper you may find in the gym. You can adjust the height of the platform you are stepping on to and also the weight you are holding.
Hope this discussion was helpful and it’s yet another important reminder to keep on weight training.
- Another study showed weight training produced no significant increase in bone density.[2. http://onlinelibrary.wiley.com/doi/10.1002/jbmr.5650050208/abstract ↩
- Medical Note: the article cites two papers that indicate weight lifting decreases BMD, but as mentioned those are outliers. Furthermore, the studies were very poorly done with a very low number of participants. These can be ignored. ↩
- http://europepmc.org/abstract/MED/9927006 ↩
- http://onlinelibrary.wiley.com/doi/10.1359/jbmr.1922.214.171.1240/full ↩
- Medical Note: it is a definite fact that bone growth and repair follows what’s called “Wolf’s law,” which basically states that bones grow and remodel by increasing density at areas of the highest stresses. For example, some of the densest bone in the body is in the proximal femur near the hip and in the talus, and ankle bone, yet some of the least dense bone is in the proximal humerus or shoulder because the stresses placed on those locations are very different. Therefore sedentary individuals with other risk factors for low BMD are at a much higher risk of fracture than active individuals who participate in axial loading type exercises. Also, men and women reach peak BMD in their 20s (women earlier than men) and density slowly declines from that point forward. It would be wise to start taking Vit D (up to 60% of Americans are deficient) and calcium supplements starting around that time to help maintain BMD as high as possible and to slow the decline. This in combination with weights is probably the best for BMD. ↩
- Bisphosphonates, used to treat osteoporosis, have been actually linked in increased fracture risk in recent studies. ↩