In part one of this series on why strength training is critical in midlife, we talked about muscle loss, or sarcopenia. Muscle loss affects both men and women, not equally, but significantly.
There’s another catastrophic loss that affects females more profoundly than males, especially after menopause.
Yup, we women can add another fun Greek word to the list of things we have to deal with as we age: “osteopenia,” and its uglier relative, “osteoporosis.”
“Osteopenia” literally means “bone poverty.” As with muscle, if left to their own devices with no intervention as we age, our bodies start to break down our bones. In women, the loss of estrogen and other hormones after menopause exacerbates this loss.
Brittle bones break
Left unchecked, osteopenia tends to degenerate into osteoporosis: the bones become porous, more brittle and prone to fracture.
No doubt you’ve known an older person who broke a hip or other bone after a seemingly inconsequential fall. That’s the work of osteoporosis. 30-50% of women age fifty and over (and up to 20% of men) are at risk of an osteoporotic fracture.
Why is this so important? In older people, broken bones—especially hips— often lead to a serious and rapid decline. Both physical and mental health suffer, which may lead to a loss of ability to live independently. And that loss typically leads to a vicious cycle of further decline.
Hip fractures are associated with a significantly increased risk of death in people over age 65—especially during the first year after the fracture, but even eight years and longer after a broken hip. Of course, as mentioned in part one, if one is also frail, these risks are magnified even more.
Men suffer bone loss too, but it happens later and less frequently than in women. Females over 50 are twice as likely to have osteopenia and 4x more likely to have osteoporosis. Women also suffer hip fractures much more frequently than men.
Age when rapid decline of bone mass begins
Average four-year bone loss
Prevalence of hip osteopenia over age 50
Prevalence of hip osteoporosis over age 50
Data source: Gender Disparities in Osteoporosis
Hips aren’t the only bones that suffer from osteoporosis. Vertebrae fracture too. This can cause osteoporotic kyphosis: that hunched-over appearance we see all too often in elderly people, especially women.
Hiding in plain sight
Bone loss is rampant even in women who are still considered to be in midlife–and it progresses fast. 54% of postmenopausal American women have osteopenia. 30% already have full-blown osteoporosis, and that increases to 70% of us by age 80.
If you’re a post-menopausal woman, it’s actually statistically likely that you already have osteopenia. You may even have osteoporosis. But you probably don’t know about it if you haven’t yet suffered a fracture.
If you want to find out, you can speak to your physician about getting a DEXA scan. Out of pocket, they typically cost a couple of hundred dollars. In the U.S., Medicare typically covers them, if you have it. If you’re not yet 65, private health insurance may pay for this test, but you’ll need a medical referral.
Creatures of gravity
Human bodies evolved in a constant fight against gravity. As a result, like our muscles, our bones respond to the demands gravity places on them by adding more tissue. And, like muscles, they get stronger when we subject them to progressively heavier loads over time.
Loading bones with weight stimulates bone-forming cells called osteoblasts. Simultaneously, it inhibits the activity of osteoCLASTS, which are the cells responsible for breaking bone down.
In younger people, these two types of cells work in balance to maintain bone health, but as we age, osteoclast activity may start to outpace the osteoblasts’ ability to keep up. (Estrogen loss makes this imbalance much more common in women than in men.) More bone gets broken down than gets built to replace it.
As a result, we suffer a net loss of bone tissue, and our bones become porous and brittle. If we do nothing to address the issue, they get weaker. And weaker. And weaker.
Eventually, they start to break.
Along with making sure to consume enough calcium and vitamin D, the only significant way to prevent degenerative bone loss and disease is through weight-bearing exercise.
This is truly a case of use it or lose it.
You can’t run from bone loss
Like muscles, bones respond by creating new tissue only when stimulated by loads greater than they normally have to deal with from day to day. This means that just going about our normal business will not protect our bones, unless our normal business happens to involve progressively overloading our skeletons.
If you’re 50 but you work for UPS and carry heavy packages for a living, your bones may be in pretty good shape (although without a scan, you can’t be sure).
Most of the rest of us have to go above and beyond to place sufficient demand on our bones to coax them into adding mass rather than losing it. How we attempt to do that matters a great deal.
The evidence is clear that low- or non-impact exercise like swimming, cycling, and walking, while very good for you in other ways, does NOT stimulate bone growth.
The evidence is less clear about high-impact exercises such as running and jumping. These activities subject our bodies to forces greater than our bodyweight, but it’s not clear whether they help with bone density. Conflicting results have come out of studies looking at this question (typically focused on young athletes, not older people). And at least some of these studies have found that recreational running alone does not provide enough stimulus to increase bone density.
I want to take a moment here to emphasize this, because a shocking number of usually reputable information sources suggest that walking, running, and other similar forms of exercise will mitigate osteopenia.
Yes, any exercise beats being sedentary, but in the case of bone loss, only barely.
Resistance training is king
And there’s another consideration for people who have already progressed into full-blown osteoporosis: brittle bones are more likely to break under the force of high-impact activities. For this reason, according to the Bone Health and Osteoporosis Foundation, most people with osteoporosis should not jog or run.
For some of us, myself included, high-impact exercise causes other problems. People dealing with certain types of joint issues or cartilage loss simply can’t jog or run, even if doing so would help them maintain bone health (and again, researchers do not agree about benefits for bone health from these types of activities).
In my case, I’ve had multiple knee surgeries and have very little cartilage in one of my knees. Doctors advised me many years ago that high-impact exercise would likely cause serious osteoarthritis in my knees and necessitate a knee replacement.
Very little disagreement exists, however, about the bone density benefits of resistance training (lifting weights), a non-impact activity that without any doubt at all DOES stimulate bone growth.
And as a reminder, running and other forms of aerobic exercise do not prevent sarcopenia, which is osteopenia’s evil henchman. In the interests of killing these two nasty birds with one stone, even if you already jog/run or do other high-impact aerobic exercise, you will still benefit from adding weight training to your exercise routine. Research shows that adding even one or two weight-training sessions per week to a running routine may have a significant positive effect on bone density.
Teaching old bones new tricks
What’s maddening is that if you ask just about any middle-aged woman, she’ll know it’s important to get enough calcium and vitamin D to protect her bones.
THAT message has been conveyed quite successfully.
Unfortunately, even with sufficient calcium intake, bone loss will still occur if you’re not also engaged in load-bearing exercise. Yet the average woman has no idea that this is true, and has never even contemplated picking up a barbell.
It’s time to change the narrative.
The medical world used to believe that we could only build bone mass prior to hitting midlife, and if we hadn’t put on enough bone by the end of our 30s, we’d missed the window. We faced an osteoporotic future and there was nothing we could do about it.
But I’m delighted to tell you it turns out that with a good strength training program, we absolutely CAN add bone mass in midlife and beyond, and halt (and in some cases even reverse) osteopenia and osteoporosis.
One key point to understand here is that where bone density is concerned, the effect of strength training is highly localized. That is, bicep curls will not improve the density of your hip bones or your vertebrae. The bones that are directly impacted by the forces being applied are the ones that will respond with new tissue.
Therefore, to take care of bone health and avoid/reverse osteopenia and osteoporosis, we need to engage in full-body training that includes heavy compound lifts such as squats, deadlifts, and overhead press. (Contrary to what many people over 50 fear, with proper instruction and a well-designed program, these exercises are completely safe for the vast majority of us.)
It’s certainly true that the more bone you can get while the getting is good, the better. And it IS easier to build bone mass when you’re younger. So if you’re under 40 and not lifting yet, there’s no time like the present.
But I’m here to tell you that if you didn’t lift in your youth, it’s NOT too late to give your bones a turbo-boost with resistance training–even if you’re in your 60s, 70s, or 80s.
Don’t wait. Start now!
Next time: how weight training helps fight insulin resistance and cardiovascular disease!