Most people today understand that building and preserving muscle matters. You’ve probably heard of sarcopenia (age-related loss of muscle) and the importance of strength training for metabolism, mobility, and longevity.

But it’s not just muscle we lose as we age. It’s bone and muscle together.

This combined condition, osteosarcopenia, is increasingly recognized as one of the biggest drivers of frailty, fracture risk, and loss of independence. And yet, while muscle has become part of the longevity conversation, bone is still largely overlooked.

Part of why we’re seeing higher rates of osteopenia in both men and women is that modern life has become so sedentary. Bones and muscles need to be challenged! We’ll talk about exactly how to do that further down.

The good news is that bone is living tissue, which means it retains the capacity to adapt. Even in people with osteopenia or osteoporosis, appropriately targeted exercise can improve bone density and strengthen the musculoskeletal system over time.

|WHY BONE HEALTH DESERVES MORE ATTENTION

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​As this chart illustrates, in adults over 50:

• 20% of women and 5% of men have osteoporosis
• 52% of women and 36% of men have low bone mass

Approximately one in three women and one in five men over age 50 will experience an osteoporotic fracture in their lifetime. Even before osteoporosis develops, osteopenia is extremely common, often silently progressing for years until a fracture occurs.

So the goal is not just to maintain muscle mass. It’s to build and preserve musculoskeletal resilience (bone and muscle together), so that we can preserve mobility, strength, balance, independence, and quality of life as we age.

|WHY WALKING ISN’T ENOUGH

For years, the standard advice for bone health has been simple: walk more.

And don’t get me wrong, walking is beneficial. It supports cardiovascular health, metabolic function, balance, and overall well-being.

But when it comes to bone density, walking alone is usually not enough. Why? Because bone responds to mechanical load, and that load must exceed what the skeleton experiences in daily life. Walking, while technically weight-bearing, is typically too low in intensity, too repetitive, and too familiar to the body to stimulate a strong adaptive response.

The forces generated during walking often fail to reach the threshold needed to activate bone-forming cells.

This is why walking can absolutely be part of a healthy lifestyle, but why it’s not, by itself, a bone-building strategy.

| BONE IS A LIVING TISSUE THAT RESPONDS TO LOAD

Bone is constantly being remodeled.

Cells within the skeleton sense mechanical strain and respond by strengthening the structure, but only when the signal is strong enough. This is the essence of the mechanostat theory.

For bone to adapt and become stronger, the loading signal must be strong enough, fast enough, and frequent enough to challenge the skeleton.

​Research shows that bone responds best to loading that is:

• Dynamic rather than static
• Rapid rather than slow
• Varied rather than repetitive
• And intense enough to create meaningful strain

Interestingly, once the load is sufficiently challenging, relatively few repetitions may be needed to stimulate bone growth.

Bone cells also become less responsive to repetitive loading over time.

This means short bouts of loading with recovery periods may be more effective than doing the same movement continuously. And because bone adapts to familiar movement patterns, multidirectional movement creates a stronger adaptive response than repetitive movement in a single direction.

Bone, like muscle, mitochondria, and the nervous system, becomes stronger through this rhythm of stress, recover, repeat.

| SO, WHAT EXERCISES WORK BEST (ACCORDING TO META-ANALYSES)

The most effective approach for bone health appears to combine:

• Resistance training
• Plus high-impact aerobic exercise (such as running, stair climbing, skipping, jumping, or higher-intensity aerobics)

Resistance training strengthens bone by generating force through muscle contraction, while weight-bearing and impact activities add additional mechanical loading on the skeleton. Together, they create a stronger signal for bone adaptation than either alone.

Studies show this combination can improve bone density, muscle mass, and strength in both women and men, particularly at the spine and hip.

Research in postmenopausal women consistently finds that combining resistance training with high-impact weight-bearing exercise produces some of the greatest improvements in bone density, and similar benefits have been seen in middle-aged and older men.
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Here are a couple of visuals so you can see exactly how effective the combination is compared to individual exercise interventions (data from this 2025 study in Nature’s Scientific Reports):

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AE = aerobic exercise; RT = resistance training; walking = leisure pace, daily activity-level effort, highly repetitive

Different forms of exercise create different signals for bone adaptation. Here’s a simplified way to think about how the evidence stacks up:

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|A PRACTICAL BONE-BUILDING EXERCISE PROTOCOL

A practical weekly structure might look like this:

Resistance Training: 2–3 Days Per Week

The strongest improvements in bone density tend to occur when:

• Load progressively increases over timeIntensity reaches roughly 80–85% of one-repetition maximum (1RM)Training is performed at least twice weekly
• And exercises target the large muscle groups around the hips and spine

These exercises can include:

• Squats
• Deadlifts or hip hinges
• Lunges
• Step-ups
• Leg presses
• Rows
• Overhead presses
• Chest presses
• Weighted carries like farmer’s carries

Resistance can come from dumbbells, barbells, kettlebells, resistance bands, machines, or even body weight when appropriately challenging.

The key is not simply “lifting weights,” but progressively challenging the muscles and skeleton with enough load to create an adaptive response.

Note that current osteoporosis guidelines often recommend more moderate-intensity training (around 70–80% of 1RM for 8–15 repetitions), which may improve strength and function but may not always provide a strong enough loading signal to fully stimulate bone formation.

Emerging evidence suggests that, when appropriately supervised and progressed, higher-intensity resistance training may produce a more robust osteogenic response.

Higher-Load Aerobic or Impact Activity: 2–3 Additional Days Per Week

This could include:

• Brisk uphill walking
• Stair climbing
• Jogging intervals
• Hiking on uneven terrain
• Racquet sports
• Dancing
• Skipping
• Small hops or jumps if appropriate

The goal is not exhaustive cardio, but dynamic loading that challenges the skeleton in varied ways.

Remember that bone responds best to loading that is dynamic, rapid, and varied, not endless repetition. Have fun and switch things up!

| PROGRESS GRADUALLY

For people new to exercise or who have osteoporosis, the key is gradual progression.

A sit-to-stand may eventually become a squat with weights. Stair climbing may progress to faster intervals or loaded carries. Small, consistent increases in challenge are what stimulate adaptation.

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In addition to supporting bone and muscle, which on their own are integral to longevity and quality of life, HIIT and resistance training improve mitochondrial function and power your cells with the energy they need for repair and growth. This is another way these kinds of exercises can help you live a longer, stronger life. That’s what this is all about!