Bone Density – It’s not just muscle that you need to hang on to as you age, underneath the muscle lies bone and, it too, declines with age. Bone is in a constant state of turnover throughout life. Over the course of a lifetime, your body repeatedly resorbs old bone and builds new bone tissue. It’s a dynamic tissue just like your muscles are.
Before the age of 20, your body builds more bone than it resorbs and you get a net increase in bone tissue. You need it because you’re still maturing. But as the years’ pass resorption catches up with and surpasses the building of new bone, leading to gradual bone loss. How rapidly this takes place depends on a variety of factors, including genetics.
Bone building and bone resorption are influenced by hormones, especially estrogen. After menopause, estrogen levels decline in women and that’s when bone loss speeds up and the risk of osteoporosis and fracture rises as well. You can’t control the loss of estrogen unless you take supplemental estrogen, but, there’s a lifestyle habit that can help you preserve and even build new bone tissue. That habit is exercise.
Exercise and Bone Health: Which Types Work?
Not all types of exercise are effective for building new bone tissue. Bones must be subjected to a minimum amount of force or stress to be coaxed into growing. Doing an easy workout with light weights won’t get you far in terms of building denser, stronger bones. Here are workouts that CAN deliver results for your bones.
Plyometrics is one of the most effective types of training for stimulating bone growth. Plyometrics are exercises that stretch and contract muscles quickly so that power is generated. Some people refer to it as “jump training” since jumping exercises are very much a part of plyometrics. Examples of plyometric moves are squat jumps, cone jumping, broad jumps, jumping onto a platform, tuck jumps, split jumps, etc.
What makes plyometrics so effective for building new bone? When you do these moves, you bend your bones slightly. While it sounds painful, it’s actually a powerful stimulus for laying down new bone tissue. Plus, the shock of landing on the ground with force also promotes new bone growth.
In fact, a little jumping is one of your best bets for building bone strength. In a study published in the American Journal of Health Promotion, 60 women between the ages of 25 and 50 jumped 10 times a day, twice daily while resting 30 seconds between jumps. After four months, the bone density in their hips had increased by 0.5%. You don’t have to do plyometric training to get in your jumps, simply grab a jump rope!
Other High-Impact Exercises
High-impact exercises are those where both feet leave the ground at the same time. Examples of high-impact exercises are running, jumping rope, and high-impact aerobics. Like plyometrics, the force of your feet hitting the ground is what stimulates the bones to grow. However, your bones adapt to exercise like running or jogging since you’re doing the same movements over and over. Plus, if you run or jog for long distances, especially if you’re eating a calorie depleted diet, you can actually experience bone loss. Some studies also suggest that brisk walking helps build bone in older women, although you must walking at a challenging pace to get the benefits.
Heavy Resistance Training
When you resistance train to build bone, you need a heavy resistance to reach the threshold, or minimal essential strain, required for activating bone-boosting cells called osteoblasts. The minimal essential stress is approximately one-tenth of the force you’d have to apply to a bone to fracture it. This corresponds to a resistance of around 80% of one-rep max. So, you won’t build significant bone mass lifting light weights. Lighter weights simply don’t signal bone-building cells called osteoblasts to lay down new bone.
So, heavy weight training works – but what kind of moves are best? One exercise to definitely include in your bone-boosting routine are squats. Although it usually takes months to see improvements in bone density through training, one study found significant improvements in bone density in the femoral neck and lumbar spine in participants who did 12 weeks of squat training. Compound exercises, in general, are best for stimulating bone growth.
Bone Density: Exercise that Doesn’t Build Bone
As mentioned, not all exercises are effective in boosting bone density. Cycling and swimming are good for the cardiovascular system but they won’t improve the health of your bones. In fact, some studies show that cyclists who pedal long distances can lose bone density. One study found that cyclists are at particularly high risk of bone density loss in the lumbar spine.
The Bottom Line
Preserving bone density is just as important as holding on to your muscle as you age. Although it won’t necessarily build bone, yoga and tai-chi are beneficial because they can improve your sense of balance and help you avoid a fall that could lead to a bone fracture. Surprisingly, one study showed that women who did yoga showed an increase in spinal bone mineral density – another reason to add yoga to your routine.
If you already have a loss of bone density, talk to your doctor before starting an exercise program. Also, know that improvements in bone density, even with regular exercise, come slowly. Expect it to take four to six months to see results. Just as you vary the stimulus you place on your muscles when you train, do the same for your bones. Do plyometrics some days and focus on heavy resistance training on others. Add some variety, but make sure you’re telling those bones to grow.
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