If you’re going to fall and break something, you should at least have a good story to tell.
I have broken nine bones. No, I was not abused. Some stories are better than others. The last bone I broke, the ulna in my left arm, involved a ski jump. Good story, except for the part about me being left-handed.
The goal for most people is to keep bones intact. For aging populations, exercise is a critical component of strengthening bones to preventing fractures.
If you move a lot, lift heavy things, walk, jog, cycle, jump, dance, do Pilates, hike or ski, then your muscles and connective tissues will be stronger and more functional. You’ll be more flexible, coordinated and agile.
Aye, but here’s the rub.
Exercise puts you at greater risk. Sure, you’re stronger and more coordinated, but the person going out for daily jogs is more likely to go flying after slipping on something than the person who sits all day. Your ability to stay upright increases, but the risk that you could fall increase too. It’s a Catch-22.
Just do whatever you want.
Psych! I’m not letting you off that easy, because exercise increases bone density and, more importantly, bone strength.
Consider your femur (thighbone). Imagine you put a bunch of extra weight on your back and move around, and up and down. That extra downward force causes the bone to bend from the weight. When that happens, previously dormant things called osteoblasts migrate toward the bone when it bends, and they lay down collagen fibers. These collagen fibers mineralize, and that yields new bone growth. Fantastic!
That’s the theory, but there isn’t a lot of consensus in the research about what this means for the average person. I did some digging, and discovered that when it comes to the effect of exercise on the bone health of aging populations, Wendy Kohrt is the expert.
I started off by asking her if resistance training actually increases bone density.
“It can happen,” said Kohrt, who is a professor of geriatric medicine at the University of Colorado. She explained that we can’t say with absolute certainty it happens in humans, but the indications are that it does.
So what are the benefits of exercise on new bone development?
“We generated increases in the neighborhood of 2 percent,” Kohrt said. That sounds . pathetic. But wait!
Kohrt explained exercise elicits similar bone growth improvements as do medications, but the true difference lies not in the increase in bone density, but in bone strength. With drugs, it’s a 1 to 1 ratio. If you increase density 2 percent, you increase strength 2 percent. With exercise, and this is being conservative, it’s a tenfold difference. Kohrt explained a 2 percent increase in bone mass can translate into a 20 percent increase in bone strength, and perhaps as much as 40 percent.
Running and jumping is going to do more than walking, and heavier lifting will generate a better result than lighter loads. “We start people off with moderate lifting, but work them up to where they can only lift it 6 to 8 times and then are fatigued,” she said. Less important is volume; 75 minutes of vigorous or 150 minutes of moderate exercise is enough. “The bottom line is anything is better than nothing.”
“I recommend they engage in a variety of activities,” Kohrt told me. “People become unidirectional as they age.” Instead, they need to move in multiple directions, carefully pushing the limits of twisting, turning and lunging to keep the entire system strong.
And less breakable.
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