Can Exercise ALONE Increase Bone Density?

If I’ve heard the following statement once, I’ve heard it a thousand times…

“All you need to increase your bone density is exercise.”

Maybe you’ve heard it too. And it’s exactly what you want to hear if you’re struggling with bone loss. A quick, simple fix to put your bone mineral density back on track. Fantastic!

But here’s the dilemma: just because it’s a common belief doesn’t necessarily mean it’s a correct one.

So, is exercise alone really enough to increase bone density? Let’s see what the research says and put the debate to bed once and for all…

What the Research Says

To get to the facts, I took a deep dive into the peer-reviewed research and read every relevant study I could find. The studies fell into one of two categories:

1. Studies that examine the relationship between exercise and fracture risk
2. Studies that examine the relationship between exercise and BMD

You can see a snapshot of the dozens of studies I researched in the two tables below. In fact, I read about 85 different papers. From there, I selected a handful which were conducted properly (what we would consider quality papers for inclusion) and summarized their findings.

Exercise and Fracture Risk

Exercise and BMD

What the Research Means for Your Bones

After looking through the research, the answer is clear: exercise alone isn’t enough to increase bone mineral density. Especially for people who are already experiencing bone loss. Only one of the studies in the table above showed any support to the claim. And even then, it only showed evidence of maintaining bone density, not increasing it. Plus, all the participants took calcium and vitamin D supplements for the duration of the study, so it’s unclear if exercise alone provided any benefit.

The studies on exercise on fracture risk weren’t too promising either (except for hip fractures)…

So here’s what you really need to know: Improving your bone mineral density (by the biggest percentage possible) takes a combination of factors, and exercise is one of them. I’ll outline the others in a moment…

So, is exercise still important for healthy bones? You bet!

Exercise combats sarcopenia

Sarcopenia is a common condition as we age, where muscle mass is lost and replaced with fat. The exact amount of muscle loss varies from person to person, but recent research suggests that the average rate for people over 70 is 0.5-1% per year.

As that happens, you become weaker, and it further affects the decline in balance associated with aging. And this significantly increases the risk of a fall.

What’s more, a decrease in muscle strength leads to a decrease in bone strength too. You see, the skeletal and muscular systems are tightly intertwined. The strongest mechanical forces on your bones are those created by muscle contractions. And these muscle contractions condition your bone density, strength, and microarchitecture (the internal structure of your bones.)

Fortunately, you can reverse the effects of sarcopenia with progressive resistance training. A 200% increase in strength isn’t unheard of in just a few months! Although the increase in muscle mass is usually around 10% in older adults.

Take me as a prime example! I’m approaching my 70th birthday, and over the last year my weight has only dropped 1.4 pounds, but my body fat percentage has dropped from 23% to 16.5% The muscle definition in my arms, legs, back, and abs is significantly more noticeable too! When I’m doing a plank, I can see muscles in my arms (mainly triceps) that I never saw before. And my ability to do some exercises has increased quite a bit too. Now I’m putting 3-pound weights on my legs when I do the ‘diamond’ exercise and on my pelvis when I do hip raises, or I just can’t get the burn!

So what am I doing differently?

I’ve been doing a one-hour barre class every day of the week. (Barre is an exercise class that uses a ballet barre for a lot of the moves- I LOVE it!) I’ve been out in the garden a lot too. You might not think it, but gardening is great exercise.

I’ve made a few diet changes too. I’ve completely cut out refined/highly processed carbs (think corn chips, potato chips, and bread) and only eat whole grains now. I’ve upped my protein intake too– I aim for at least 60 grams a day now. And it’s made a big difference in my stamina and energy level! So I can work out harder and longer… I may be in the best shape of my life to date!

Exercise turns on and extends the life of osteocytes

Osteoblasts are the cells that build your bones. After they’ve done their bone-building, they become embedded in the bone matrix they’ve produced and turn into osteocytes. Osteocytes are very long-lived cells (their average half-life is 25 years) that form a signaling network in your bones. It’s like the nervous system in the rest of your body. This network transmits signals to direct and balance the activity of your bone-building osteoblasts and your bone-resorbing osteoclasts.

And here’s where exercise comes in: osteocytes tend to die off as you get older. Especially if they’re not stimulated by “mechanotransduction.” Now, in plain English, mechanotransduction means a movement that puts stress on muscles, which in turn put stress on bones. In other words, exercise!

Exercise-activated osteocytes increase your production of osteoblasts and muscle cells

So, those osteocytes I was just talking about have even more bone benefits! In response to exercise, osteocytes send signals that increase the pool of mesenchymal stem cells. These are stem cells that can grow up to become osteoblasts, adipocytes (fat cells), or muscle cells.

And here’s the catch: you tend to produce fewer mesenchymal stem cells as you age. Plus, most of them become fat cells — unless you exercise. The cycle goes like this:

1. Exercise turns on your osteocytes
2. More osteocytes increase the number of mesenchymal stem cells you produce…
3. …AND tells them to become osteoblasts or muscle cells instead of fat cells

Only one other strategy will effectively increase your production of mesenchymal stem cells AND convince them to become either osteoblasts or muscle cells instead of fat cells. So what is it? Consuming enough of the omega-3s, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

For more detail on the how and why read my dedicated post by clicking here.

Lastly, when osteocytes are turned on in response to mechanical loading (putting stress on muscle through exercise), they stop secreting a protein called sclerostin. And they increase the secretion of proteins involved in Wnt signaling too. Now, sclerostin inhibits the development of osteoblasts and bone formation. And Wnt signaling promotes the production of both bone-building osteoblasts and myocytes (muscle cells).

How important is this? Well, the newest (not yet approved) drug in the pipeline, was created to be a patentable antibody to sclerostin. As more people are exposed to this drug in trials, I’m sure I’ll be reporting on a whole host of adverse side effects. The few studies that have run already show an increased risk of vascular calcification, stroke and “cardiovascular events” (i.e. heart attacks). Along with a potentially increased risk of cancer too.

But, you don’t have to expose yourself to these nasty side effects. All you need to do is exercise!

Regular, vigorous exercise doesn’t increase BMD, but does lower your risk of hip fracture

So as you can see, exercise DOES have benefits for your bones. And given the information I’ve outlined above, it’s not surprising studies show that people who engage in regular, vigorous physical activity are 20-40% less likely to suffer a hip fracture. (Compared to sedentary people).

But the fact remains. There is next to no evidence to show exercise alone increases bone mass. The best that trials show is exercise slowing bone loss.

Still, that’s nothing to scoff at! Minimizing further bone loss as you age is a significant achievement. But there’s a catch: Exercise won’t deliver this benefit without calcium. Which brings us to the next section…

The Importance of Nutrition for Your Bones!

You wouldn’t tell a bodybuilder to forget protein because all they need for building big muscles is weightlifting, right? Well, the same principle applies to your bone density. You can’t rely on exercise alone. Remember when I said increasing your bone density requires a combination of factors? Well, here they are:

The three factors for building bone:

Calcium

How is calcium related to exercise?

Optimal calcium intake is THE deciding factor in whether exercise delivers anti-fracture benefits or not.

Overwhelming evidence shows that individuals who consume low levels of calcium have lower bone mass (and greater risk of fracture) than age-matched individuals who consume adequate or high levels of calcium. And that goes for young people as well as older folk.

Plus, there’s a threshold for total dietary calcium intake of around 1,000 mg/day. Below this amount, physical activity has little to no effect on increasing bone mass.

A review of data from 16 exercise intervention trials in peri- or postmenopausal women looked at the effects of calcium intake and exercise on BMD in the spine and radius (the shorter and smaller bone of the two long bones in the forearm). In the spine, increasing calcium intake without the stimulus of exercise had a very minor effect. But at calcium intakes of less than 1,000 mg/day, exercise failed to improve spine BMD at all.

It took both the stimulus of exercise and sufficient calcium to increase BMD. Even when calcium was adequate, the effects of exercise on the radius were negligible. But this is probably because most training programs don’t put sufficient stress on the radius to make a difference.

In addition, physically active people may need even more calcium to support the increased bone formation potentially stimulated by physical activity. This could explain why the research on exercise and bone formation shows such inconsistent results. The lack of bone building in response to exercise could be because the higher levels of calcium needed weren’t available.

Even very high-intensity resistance and impact training don’t increase BMD in postmenopausal women with osteopenia and osteoporosis. In the “LIFTMOR trial,” 101 postmenopausal women with low bone mass were randomly assigned to either; eight months of twice-weekly, 30-minute, supervised high-intensity resistance and impact training (HiRIT) or a home-based, low-intensity exercise program (CON).

All participants (in both groups) increased their muscle strength. But, the CON group lost BMD at all sites measured. And the HiRIT group mostly maintained BMD, but some actually lost BMD. Remember, you lose about 1% of your bone density every year. So this study shows that even high-intensity exercise isn’t enough to counterbalance that loss. And what’s more, these women were consuming a diet that provided far more calcium than typical– around 900 mg or more a day. (Just under that magic threshold of 1,000 mg/day).

Plus, this was a serious workout. In one exercise, (jumping chin-ups with drop landings), participants had to grasp an overhead bar with their shoulders and elbows flexed to 90 degrees, and their hands shoulder-width apart with an underhand grip. The participants then jumped as high as possible while pulling themselves as high as possible with their arms. At the peak of the jump, the participants dropped to the floor, focusing on landing as heavily as comfortably possible.

The good news is that no fragility fractures occurred. So, this study shows that women with osteopenia, or even osteoporosis, can engage in high impact training when supervised. But frankly, I flinched just reading about those jumping-chin ups — OUCH! Could you do them?

The bottom line: Exercise without sufficient calcium intake will not increase BMD

In postmenopausal women, the mechanical stress of exercise appears to provide a necessary stimulus for increased skeletal incorporation of calcium. But adequate calcium must be present for bone mineralization to take place. And don’t forget, you need vitamins D and K2 to work with calcium to benefit your bones.

Protein

Protein is the crucial macronutrient for muscle growth. And remember, your skeletal and muscular systems are tightly intertwined. So basically, protein builds your muscle mass, which helps to keep your bone health in check.

But as you age, you become less able to convert protein into muscle. This is a contributing factor for sarcopenia, which I mentioned earlier. And if you recall, I stated that exercise combats sarcopenia. Well, eating enough protein is crucial too! But that’s where things get a little confusing. You see, the original recommended daily allowance (RDA) of protein for older adults doesn’t appear to enough.

The original RDA is 0.8 g per kg of body weight. But that amount was set with preventing a deficiency in mind. Not for promoting optimal health. And experts are now suggesting that the original RDA could lead to muscle loss in older adults!

Don’t worry though. You can read all about the new RDA for protein experts are suggesting in our “Everything You Need to Know About Protein and Bone Health” post. It covers the best sources of protein, and why it’s important for your bones in more detail too.

Vitamin D and Omega-3s – Two Critical Nutrients for Muscle and Bone

Vitamin D

Vitamin D helps you absorb the calcium you consume. But that’s not all. A number of recent meta-analyses show that vitamin D treatment reduces the risk of falls too. Here’s why; muscle fiber membranes are loaded with vitamin D receptors. And their exposure to vitamin D triggers muscle protein synthesis- that’s how muscles grow!

Now, the ‘Institute of Medicine’ still claims there isn’t sufficient evidence for vitamin D’s importance to prevent sarcopenia. But in Europe, a panel of experts determined a vitamin D level of at least 30-44 ng/mL (nanograms per milliliter in your blood) was necessary for musculoskeletal health. The “at least” here is important. Even 44 ng/mL of vitamin D isn’t enough for your bones. For bone and immune health, you need 50-80 ng/mL.

Omega 3s

Omega 3s are most notable for their anti-inflammatory properties. (Inflammation causes bone loss!) But omega 3s also help preserve lean body mass, too. In particular, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

These two omega 3s increase the activation of an enzyme called mTOR. Now, mTOR activation is a big deal. mTOR is THE key regulator of muscle protein synthesis. And muscle protein synthesis is the process of repairing and building muscles tissue when you exercise! mTOR regulates a bunch of other vitally important cellular processes that enhance health and slow the aging process too!

The Nutrition Roundup

So, calcium, protein, vitamin D, and omega 3 fatty acids are the nutrients proven to boost the effect of, or maximize your exercises. But don’t forget, there are a total of 13 minerals your bones crave (protein and omega 3s not included).

Getting all of the above into your diet is a challenge though. Especially given the increased recommended daily intake of calcium for people over 50 (1,200mg/day). At my age, my appetite just isn’t what it used to be!

But thankfully, AlgaeCal’s Bone Builder Pack (AlgaeCal Plus + Strontium Boost) provides all 13 of those bone-supporting minerals. And that includes 720mg of super-absorbable, plant-based calcium! (The average diet provides around 500 mg/day of calcium. So your diet + the Bone Builder Pack = the recommended daily intake of 1200 mg or more!)

What’s more, when you use the Bone Builder Pack, you’re GUARANTEED to see an increase in your bone mineral density at every follow-up DEXA scan! Yes, it’s 100% risk-free.

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Now, the Bone Builder Pack doesn’t contain omega 3s. But I use Triple Power Omega 3 Fish Oil to get my daily fix of those. It provides over 1400mg of omega 3s, including EPA and DHA which I’ve discussed in this post. And the best part? It tastes AMAZING. Not like omega 3 supplements I’ve taken before. No, Triple Power tastes like mango! And it’s in liquid form too, so you don’t have to swallow a hefty pill.

That just leaves protein. Don’t worry though; it’s super easy to add protein-rich foods to your meals. In fact, you can discover the best ones in our “Everything You Need to Know About Protein and Bone Health” post.

The Most Effective Exercises For Bones

Now, you might be wondering which exercises are the most beneficial for your bones. The good news is you don’t have to start a bodybuilding regime! But for your exercise to have the biggest impact on your bone health, you should try to tick off everything on the following checklist.

To make exercise more effective, it should:

• Be happening at least three times a week for 1 hour – An hour every day of some form of weight-bearing movement would be far better
• Be dynamic! – Include faster movements opposed to slow, static movements
• Involve some impact – For example walking, jogging, or vigorous dancing, rather than cycling or swimming
• Exceed a threshold intensity – Aim to exercise at least 70%, (preferably 85%) of your maximum effort. In other words, you should be short of breath and a little sweaty by the end
• Gradually get harder – Whatever you do needs to take some effort to do! You should gradually increase the number of times you can work a muscle or muscle group because as you get stronger, what you’re doing will get easier (a very good sign!)
• Involve short bouts of intense exercise with less intense recovery periods – Bopping till you drop is no fun. It’s not effective either. Take short breaks between exercise sets, and you’ll come back stronger
• Impose an unusual loading pattern on your bones – You do want to repeat movements until the muscles you’re using get the message to get stronger. But you don’t want your entire workout to only include the same movement over and over again. That’s boring and ineffective. You want movements that involve a wide variety of muscle groups and movement direction.

And last, but definitely not least, your workouts should be combined with optimal nutritional support: protein, calcium, vitamin D3, vitamin K2, magnesium, boron and other trace minerals.

One important note: People with severe osteoporosis should avoid impact-producing exercises and exercises that involve forward flexion of the spine (curving forward to look like a “C”) to prevent injuries. You don’t have to avoid them forever, just until you’re no longer osteoporotic.

To get you started with exercises that are beneficial for your bones, check out the exercise section of the AlgaeCal blog.

How Much Should You Exercise?

We use Metabolic Equivalent (MET) hours when we look at the intensity of exercise. The MET measures the amount of energy you burn during exercise and various physical activities.

For reference, 1 MET is equal to the number of calories burned at rest: 30-38 calories for every 30 minutes. And you burn 3-6 METs of energy with moderate exercise: 90-225 calories in a 30-minute workout.

And here’s the exciting part: The Nurses’ Health Study showed that active women with a minimum of 24 MET hours of at least moderate activity per week had a 55% lower risk of hip fracture! (Compared to sedentary women getting less than 3 MET-hours per week).

The exact number of calories you burn will vary depending on two things. How much muscle mass you have, and how vigorously you use it during the exercise. The good news here is the more you exercise, the more muscle you will have, and the more calories you will burn.

For an idea of how many MET hours various activities tally up on average, check out the following table:

Table Sources:

1. https://sites.google.com/site/compendiumofphysicalactivities/Activity-Categories/bicycling
2. http://www.whyiexercise.com/metabolic-equivalent.html
3. https://en.wikipedia.org/wiki/Metabolic_equivalent

The Bottom-Line: MOVE IT or LOSE IT

So, is exercise alone enough to increase your bone density? The short answer is no.

The majority of studies show no evidence whatsoever to support that claim. And as we saw in the table earlier, even the ones that do are really looking into exercise, nutrition, and bone health. Not just exercise and bone health.

But exercise does play a big role in your bone health. Remember, proper nutrition is the key for building bone, but by exercising and avoiding harmful toxins you’ll maximize your results.

And remember, you can provide your body with everything it needs to maximize the results of exercise AND kick-start bone building with the Bone Builder Pack and Triple Power Omega 3 Fish Oil.

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As for exercise, find activities that get you moving and aim for at least one hour a day. One hour isn’t a lot in the grand scheme of things, and your bone health is well worth the effort. And what’s more, you might just enjoy yourself!

I’d love to hear your favorite exercises and activities that get you moving, so please share them in the comments section 🙂