The Bone Health & Osteoporosis Foundation estimates that about 54 million Americans have low bone mass, placing them at increased risk for osteoporosis. Genetics, hormone levels, and lifestyle all play a role in the development and progression of osteoporosis, and if you want to reduce your own risk, diet and the right kind of physical activity are the best places to start. But what is the right kind?
Bone responds to the stress we put on it, and we need enough stress from physical activity to promote bone growth — but not too much stress, as can happen with overexercising. That’s why the American College of Sports Medicine and other organizations recommend “weight-bearing” activity, but unfortunately those recommendations have not been paired with clear examples. If you’ve always assumed that walking and resistance training (weightlifting) counted as “weight-bearing” activity, what I learned when I attended a session on skeletal health at the annual meeting of the Academy of Nutrition and Dietetics last fall might surprise you. It surprised me, too.
It turns out that walking’s technically weight bearing — you are bearing your own weight, after all — but while it’s good for your muscles, heart, lungs and mental health, it’s probably not stressing your bones enough to count. Consider this: walking is good for your joints because it’s low impact.
Ah … there’s the rub. Our bones need impact. That leaves out swimming (the water supports your weight), cycling (unless you are mountain biking on rugged, bumpy terrain) and walking (there’s always one foot on the ground, so the impact is only equal to your body weight, which isn’t enough).
A 2017 position statement from Exercise & Sports Science Australia about physical activity for preventing and managing osteoporosis did provide the clear guidance that’s long been missing. Specifically, activity needs to provide rapid impacts of at least twice your body weight, and it needs to get progressively harder as your fitness improves and your bones adapt.
ESSA’s “exercise prescription” for bone health includes impact, resistance and balance training, with some modifications based on whether or not someone already has osteoporosis.
Impact training. Running counts, and racket sports are even better. Jumping rope ups the ante further, but not as much as volleyball and aerobics. The overall impact winner? Gymnastics. Visualize sticking a dismount or handspringing across the floor, and you’ll understand why.
If you have steps in your house, you could jump off the bottom step, holding on to the handrails at first if needed, then progress to jumping off higher objects. Think 10 to 150 impacts per day, at least three days per week. It’s also important to mix up your impact activity so your bones don’t get used to what you’re doing and stop improving. This includes jumping or bounding in different directions, like when you play pickleball or tennis.
Resistance training. Lifting weights is great for muscles and it can also be good for bones if the weights are heavy and you’re working hard. The ESSA guidance recommends doing two sessions per week of eight exercises that target large muscle groups. The goal is two to three sets of each exercise, lifting enough weight that you can only manage eight repetitions. Results from the LIFTMOR (Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation) study demonstrated that supervised high-intensity progressive resistance training — using dead lifts, squats and overhead presses — can improve bone density in both postmenopausal women and middle-aged and older men with low bone mass.
Many female runners are shocked to get a DEXA scan and discover that their bone density is great in their hip and spine, but not in their wrists. Pushups — starting with hands against the wall if needed — help build strong wrists, but once they feel easier you’ll need to increase the challenge. You might progress from the wall to a chair to your knees to your toes — then try lifting your hands off the ground at the top of the pushup.
While some discomfort can be a sign that you’re getting the positive bone stress that you’re seeking, it’s important to not hurt yourself. If you already have low bone mass, are deconditioned, or are new to impact- or resistance-based exercise, a physical therapist can help you learn how to do these movements with proper technique so you don’t hurt yourself as you gradually get stronger.
Balance training. Walking heel-to-toe forward for 10 steps, then backward for 10 steps, is one idea. When that gets easy, walking on a foam mat or closing your eyes increases the difficulty, and so does adding a cognitive element like counting backward by sevens while doing the physical exercise. Always be safe, whether that means having someone to supervise you or something solid to grab on to if needed.
The best time to build our bones is from childhood through early adulthood. But later is better than never. If you know that your bone density is already declining — you’re a postmenopausal female, or you’ve been diagnosed with osteopenia or osteoporosis — anything you can do to slow down bone loss is a win.
My sister did gymnastics as a kid, played volleyball and basketball and ran track in middle and high school, then continued to run recreationally, so she probably built better bones than I did. However, I started heavy weightlifting in high school and did a lot of aerobics in my teens and 20s, so I feel OK about the foundation I laid. But I’m taking nothing for granted. I’ve added pushups and heavier weights into my resistance training sessions and dusted off my jump rope. While I don’t feel ready to jump off my 15-inch plyometric box yet — I’m working from a lower step for now — I’ll get there.
What counts as weight-bearing exercise?
