Whether or not regular exercise increases bone strength, there’s no doubt that it is good for heart health, weight control and overall health so I urge you to continue walking daily.
The idea that exercise is key to bone strength comes from studies showing that lack of exercise – among people who are bedridden, for example – leads to bone loss. So it would seem that among the rest of us, bones would benefit from activity, specifically weight-bearing exercise. However, there isn’t much evidence that common forms of exercise, such as walking, actually build bone.
The best way to avoid the age-related loss of bone mineral density that leads to osteopenia and osteoporosis is to build up sufficient bone mass early in life. Maximum bone mass is genetically determined and is reached around age 35. After that, it begins a slow decline in both men and women.
Some studies have suggested that it is possible to reverse bone loss through exercise, but the activity involved is much more strenuous than walking or even jogging. Last year (2015) researchers at the University of Missouri reported that both strength training (weight lifting) and jumping exercises helped a group of 38 active, middle-aged men with low bone mass improve their bone density. After six-months of performing these activities, the researchers found significant increases in whole body and lumbar spine bone mass but saw improvements in the density of the hipbone only among the men in the weight-lifting group. The improvements were still measurable 6 months later. The weight-lifting exercises included squats, deadlifts, lunges and overhead presses, targeted at the hip and spine. Over time, weight was increased to boost the intensity of the exercises.
I don’t suggest trying any of this on your own – if you’ve never done strength training, you need instruction to learn proper form as well as how and when to increase the amount of weight you’re working with. However, I have long recommended strength training to help maintain bone once you reach midlife. Bone is constantly being reformed by the action of opposing forces – some destructive, some constructive – in response to the stresses and demands placed on it. These changes are under precise cellular and hormonal control. Strength training causes the constructive influences to dominate.
And don’t discount the benefits of walking. Regardless of its measureable effects on bone mass, a study including more than 60,000 women linked brisk walking at least 4 times a week with a substantially lower risk of hip fracture compared to being sedentary.
Andrew Weil, M.D.
Pam Hinton et al, “Effectiveness of resistance training or jumping-exercise to increase bone mineral density in men with low bone mass: A 12-month randomized, clinical trial.” Bone, October 2015, doi: 10.1016/j.bone.2015.06.008