Losing Bone Density Isn't Inevitable — Study Shows How To Stop It

But until now, scientists couldn't fully explain why. Scientists theorized that repeated pressure stimulated bone growth, but the biological mechanism wasn’t clear. Well, a new study published in Signal Transduction and Targeted Therapy1 gets to the root of the answer. 

And it all comes down to a single protein acting as the body's built-in "exercise sensor."

The protein that helps drive bone growth: Piezo1

Researchers at the University of Hong Kong have identified that the protein Piezo1 functions like a biological switch, detecting when you move and triggering a cascade of bone-building activity in response. It senses mechanical stress—like the impact of walking, running, or lifting weights—and translates that physical signal into physiological results. 

How it works: The bone vs. fat decision

Here's where it gets fascinating. Your bone marrow contains mesenchymal stem cells that can develop into either bone cells or fat cells. What determines which path they take? According to this research, Piezo1 plays a deciding role.

When you exercise, mechanical stress activates Piezo1 in these stem cells. This triggers a specific inflammatory pathway (called the Ccl2-Lcn2 axis) that essentially tells the stem cells: "Build bone, not fat."

Without that mechanical stimulus—say, during a sedentary lifestyle—the pathway stays quiet. Therefore, stem cells are more likely to become fat cells instead. When fat accumulates inside the bone marrow, it crowds out healthy bone tissue and weakens the structural integrity of the bone.  

Over time, this increased fracture risk and leads to deterioration that’s extremely (if impossible) to reverse with current bone therapies. 

Why this matters for aging

This research helps explain a troubling pattern: as we age and move less, our bones become more fragile. According to the International Osteoporosis Foundation, 1 in 3 women and 1 in 5 men over age 50 will experience an osteoporotic fracture.

The Piezo1 discovery offers a clear contributing factor as to why. When we're sedentary, we're not activating this protective pathway. The stem cells that could be building bone are instead becoming fat cells, a process called bone marrow adipogenesis.

For health-conscious readers already prioritizing movement, this is validating news. Every time you do weight-bearing exercise, you're not just burning calories or building muscle—you're literally flipping a switch that tells your body to strengthen your bones.

Weight-bearing exercises to add to your routine: 

If you’re active, there’s a good chance you’re already doing one of the below, but be sure to incorporate a variety for the full scope of benefits. 

And if your lifestyle could benefit from more activity? Well, then this list is an excellent place to start: 

You don’t need extreme workouts to activate this pathway. Consistency matters more than intensity; regular, moderate mechanical stress is enough to signal your body to preserve bone strength.

What this means for future treatments

With this finding, researchers are now eyeing clinical application, noting that there is now “a clear target for intervention.” 

Not only can this help inform physical therapy best-practices and protocols to help people preserve bone integrity with age, but it may even lead to revolutionary drugs that can mimic exercise for those who are unable to stay active. 

The hope is that future medications could activate the Piezo1 pathway directly—essentially giving people who can't exercise the same bone-protective benefits. This includes vulnerable populations like older adults, bedridden patients, people with disabilities, and individuals with chronic illnesses who face a higher risk of fractures

“This discovery is especially meaningful for older individuals and patients who cannot exercise due to frailty, injury or chronic illness,” Wang Baile, PhD, co-leader of the study and a Research Assistant Professor at the University of Hong Kong, said in a press release. “Our findings open the door to developing 'exercise mimetics,' drugs that chemically activate the Piezo1 pathway to help maintain bone mass and support independence."

The takeaway

This research reinforces what we’ve been preaching for years: movement matters. But now we understand exactly why at the cellular level.

Every time you go for a walk, lift weights, or do any form of weight-bearing exercise, you're activating Piezo1 and telling your stem cells to build bone instead of fat. 

In other words, the habits you're already practicing aren't just good for your muscles or your heart. They're protecting your skeleton, which is truly the foundation for healthy aging.