Can You Rebuild Bone Density with Exercise? Here's What the Studies Show
- Jordan Metcalf
- 2 days ago
- 6 min read
There’s a common misconception that bones function just like the wooden framing of a house.
They don’t.
Your bones are not just passively supporting your body. They are dynamic, living tissue that is constantly being torn down and rebuilt in response to what is being asked of them.
Unfortunately, the people who have the most to gain from understanding how bones work are also the people that the medical world and society at large has repeatedly let down: women over the age of 30.
There is still a lot of misinformation out there about exercise and bone density, but the good news is that the medical community is starting to come around based on some compelling studies that have been published in the last 10 years.
How your bones work
Your bones are living tissue made up of a combination of minerals (like calcium), collagen, and cells. They are constantly breaking down and building back up based on what’s going on in the body.
In optimal conditions, worn out bone tissue is being replaced by new healthy bone tissue at the same rate.
But if you’re underfueling and don’t have enough calcium in your blood, your body will break down extra bone to use the calcium.
Or, if your hormones change (as they often do in perimenopause), it can cause more bone breakdown.
When bone density falls below a certain threshold, we classify it as osteopenia, or moderate bone density loss. Osteoporosis is a condition of severe bone density loss, and causes a much higher risk of fractures. These bone density conditions disproportionately affect women over the age of 50 due to the hormone changes that occur during menopause.
The good news is that research shows that lifting weights can build stronger bones, and women of all ages can benefit.
What Research Shows About Exercise for Bone Density
There are four studies published recently that should change how you think about exercise and bone.
A group of women in their mid-sixties, many already diagnosed with low bone density, lifted heavy weights and performed moderate to high impact jumping twice a week for eight months. Their spine bone density went up. The group doing the safe, gentle program lost bone over the same period. And the heavy lifters got hurt less, not more.
The biggest fear with low bone density is that lifting something heavy will cause a fracture. When researchers scanned these women's spines before and after, not a single new fracture showed up, and they stood up straighter than when they started.
You build most of your bone density by age 30, and then the job shifts to defending it. A group of young women spent 12 weeks doing heavy, explosive squats and added real bone density in that short window. If you're a runner in your twenties or thirties, this is the cheapest insurance you'll ever buy: the barbell work you do now is bone you get to keep later.
Calcium and vitamin D help bone density, but they mainly matter if you’re pretty deficient in one or both. For those with adequate calcium and vitamin D, you’re better off focusing on resistance training.
So how heavy is heavy?
I remember having a conversation with a family friend in her 70’s about all of this after she found out that she has osteopenia, and she was trying to figure out how to improve her bone density without costly medications that only promise modest results. When I shared the broad strokes of these studies, she said:
“Okay, so maybe I should switch to my 5 lb dumbbells instead of the 3 lb ones for my usual arm workout?”
What she said made sense in context. She didn’t really have any exposure to true strength and conditioning principles. She grew up in a society that idolized small and slender women, had minimal exposure to sports and performance in her youth, and was told that skinny means healthy.
But this research shows that switching to the 5 lb dumbbells just won’t move the needle on bone density.
LIFTMOR parameters: 5 sets of 5 repetitions of deadlift, squat, and overhead press at at least 80-85% of the subject’s 1 rep max (the most weight they could lift once).
Mosti study parameters: 4 sets of 3-5 repetitions of hack squat at 85-90% of the subject’s 1 rep max with an emphasis on going fast on the “up” portion of the exercise.
These subjects were lifting heavy. Much heavier than my friend had ever attempted to lift. She stands to gain a lot from starting now, but she has some barriers to lifting this heavy. That’s why working with a professional can be such a game changer.
But isn’t lifting heavy dangerous if my bones are weak?
The LIFTMOR study tells us that actually, it could be more dangerous to do nothing. No new vertebral body fractures happened in the heavy lifting group, but one did occur in the control group. That’s not enough to confidently say that doing nothing is more dangerous than lifting heavy, but that small finding is compelling nonetheless.
Beyond bone specific safety questions, weight lifting is a relatively safe activity compared to others like running. In fact, it has a similar injury rate as fitness walking or cycling. (1)
Speaking from my own professional experience as a physical therapist, the aches and pains that can develop related to weightlifting are often related to form or doing too much too soon. With a good training program and decent movement quality, regular weight lifting can be not only safe, but a net positive on your quality (and duration) of life.
Most bone density related injuries are fractures sustained from a fall. Strength training has been proven effective at improving bone density, but it can also improve balance reactions which can reduce the risk of falling in the first place.
Real client stories
Jane (69) came to me initially for knee and calf pain. Her goals were to be able to go up and down stairs more easily, and walk further without taking a break. As we worked on managing her symptoms, we started laying the foundation of a strength program because I knew this would help keep her symptoms at bay, and she is at a high risk for low bone density conditions like osteopenia and osteoporosis.
The first couple of times that we worked together, she was very sore. I explained that, while I don’t want her to feel that way after every session, it’s pretty common to feel that way when initiating a new strength routine. Now, Jane can do more in her sessions than when she started with less consequence, and we’ve even gotten her jumping! She doesn’t dread stairs as much as she used to, and she’s walking to work most days when the weather is good enough. These improvements took about 7 months, and she'd probably be even further along if she could do more on her own!
John (70) has been working with me 3 times per week for 3 years. My role in his life has been helping him stay consistent with his resistance training while navigating other medical barriers. If he was on his own, every ache or pain that came up would mean taking a month off of exercising. Since we’ve been working together, we’re able to treat some of the aches and pains that have come up while keeping the consistent training going. He is having fewer falls, has improved bone density measured on a DEXA scan, and even better circulation in his foot which is impaired by peripheral arterial disease.
Where to start
You have to start where you are. If you’ve never touched a dumbbell, don’t jump straight to barbell lifts without any guidance. Ideally, you’ve spent some time getting acquainted with squatting, deadlifting, bench press, and overhead press before loading up the weight.
The fastest path to lifting heavy safely is to work with a professional. Personal trainers can help make sure that your program meets you where you are, and then dial up the intensity gradually to ensure that you can stick with it.
If you have some physical barriers that prevent you from starting, like pain or injury, then working with a physical therapist is a great first step.
At Alterra, we help older adults build their bone density through resistance training all the time! If you’re local to Boston’s Back Bay and looking for help to start resistance training to improve your bone density, we’d love to help.
Book a free discovery call to see if we’re a good fit to work together.
Sources
Aasa, U., Svartholm, I., Andersson, F., & Berglund, L. (2016). Injuries among weightlifters and powerlifters: a systematic review. British Journal of Sports Medicine, 51, 211 - 219. https://doi.org/10.1136/bjsports-2016-096037
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