2 to 3 Hours of Brisk Walking a Week Can Slow Bone Loss After 40

After 40, most of us slowly lose bone. It’s quiet, painless and easy to ignore, until a fall turns into a fracture.

Exercise is the one tool almost every guideline recommends. But which exercise, and how much?

The advice has been surprisingly vague.

A big new analysis in The BMJ pulled together 124 randomised trials to answer exactly that.

The headline surprise: plain brisk walking or jogging did about as well as combined cardio and strength training for bone density.

What is the best exercise for bone density?

Here’s the short answer from this study. For bone density at the spine and hip, brisk walking or jogging came out on top, alongside workouts that mix aerobic and strength training.

Those findings fit official advice. The NHS says weight-bearing exercise and resistance exercise are particularly important for bone density.

Weight-bearing means your feet and legs carry your body weight. Brisk walking, jogging, dancing and tennis all count.

Swimming and cycling don’t. They’re great for your heart, but they put little load through your bones.

Resistance exercise means working your muscles against weight, such as lifting weights or using resistance bands. The pull of muscles on bones helps strengthen them.

If you already have osteoporosis, the NHS suggests talking to your doctor before starting a new exercise programme.

The study: 124 trials, 18,429 people

What the researchers did

The team, from hospitals and universities in China, searched four major research databases up to January 2026.

They included only randomised controlled trials in adults aged 40 or over. That’s the strongest kind of study for testing whether something works.

In total, they found 124 trials with 18,429 participants. The programmes lasted from 12 weeks to four years.

Six kinds of exercise

The researchers sorted every programme into one of six groups.

A clever way to compare doses

Comparing a yoga class with a jogging plan is tricky. So the team converted every programme into one common unit.

That unit is MET-minutes per week. It combines how hard an activity is with how long you do it.

Brisk walking for an hour, for example, counts for more than a slow stroll.

What they measured

The main outcome was bone mineral density at three spots: the lower spine, the top of the thigh bone (femoral neck) and the whole hip.

Those are the places where osteoporosis fractures hurt people most. The team also looked at fractures themselves, in 26 trials with 11,132 people.

The results: walking held its own

Bone density

Compared with no exercise, several types helped. But two stood out.

Resistance training on its own helped a little at the spine and femoral neck. Whole body vibration helped the spine, but not the hip.

The gains were small in absolute terms. But the researchers set their bar carefully.

Adults over 40 typically lose about 1% to 2% of bone density a year. So they counted a benefit as meaningful if it matched at least 1% of starting bone density.

In other words, meaningful meant roughly cancelling out a year of normal age-related bone loss.

How much is enough?

This is the most useful part of the study. The team mapped how bone density changed as the weekly dose went up.

Meaningful gains generally appeared at about 600 MET-minutes a week. The authors say that’s roughly 2 to 3 hours of brisk walking or jogging.

Benefits kept rising up to about 900 to 1,000 MET-minutes a week, then levelled off.

So you don’t need punishing workouts. A steady, moderate habit seems to do most of the work.

Fractures

Bone density is a stand-in. What really matters is whether people break fewer bones.

Here the picture was weaker. Mixed aerobic exercise was linked to 71% lower odds of a fracture, and mind-body exercise to 42% lower odds.

But those results came from small numbers of trials, and certainty was low. Brisk walking’s effect on fractures wasn’t statistically clear.

The reassuring part: no exercise type increased fracture risk. The authors found supervised programmes were safe.

Who benefited most

People aged 40 to 60 reached meaningful gains more easily than those over 60. So did men, and people with a healthy weight.

That doesn’t mean exercise stops working later in life. It suggests older adults, and people with overweight or obesity, may need a bit more of it.

The evidence for these differences was very low certainty, so treat them as hints.

Why might walking work so well?

Bone responds to strain. When you load it, bone cells sense the stress and signal the body to strengthen it.

Each brisk step sends a force of about 1.5 to 2 times your body weight through your legs and hips. That’s a repeated, moderate jolt that bone seems to like.

Heavy lifting can load bone even harder. But in older adults, programmes often use light weights for safety, which may be too gentle to trigger much change.

The authors also note that bone seems to get used to the same routine. Varying your exercise over time may help keep it responding.

What earlier research found

Exercise helps after menopause

A 2023 meta-analysis in Osteoporosis International pooled 80 studies with 5,581 postmenopausal women.

Exercise improved bone density at the spine and hip. The effects were modest, and they held whether or not women already had low bone density.

Heavy lifting can be safe

The LIFTMOR trial, published in 2018, tested supervised high-intensity lifting and impact training in 101 women with low bone mass.

After 8 months, spine bone density rose 2.9% in the lifting group but fell 1.2% in the low-intensity group. Only one minor back spasm was reported.

How it fits together

The new study agrees that exercise protects bone. Its fresh contribution is the dose, and the finding that everyday brisk walking belongs near the top of the list.

LIFTMOR shows that carefully supervised heavy training is another strong option, even for people with low bone mass.

How much should you trust this?

Promising. It’s a large, well-designed analysis of randomised trials, but many of those trials were small or at risk of bias.

What makes it convincing

• It included only randomised controlled trials, 124 of them.
• It compared six exercise types in one analysis, instead of one at a time.
• It worked out doses, not just whether exercise helps.
• The review was registered in advance, and the code and data are public.
• The authors declared no competing interests.

What makes me cautious

• Certainty for the top results was only low to moderate.
• Only 28 trials (23%) were at low risk of bias. Exercise trials can’t hide from participants what they’re doing.
• Small trials of walking reported unusually large effects, so walking’s benefit may be overstated.
• About 73% of trials included only women, so results for men are less certain.
• The fracture results rest on few trials, and bone density is only a stand-in for fractures.

What this means for you

If you’re over 40, your bones will thank you for moving more. The good news is that you don’t need a gym.

• Aim for about 2 to 3 hours of brisk walking a week. That’s about 20 to 25 minutes a day.
• Add muscle strengthening on 2 days a week. Weights, resistance bands or bodyweight moves all work.
• Choose weight-bearing activities. Walking, jogging, dancing and tennis load your bones; swimming and cycling don’t.
• Consider tai chi or yoga. Mind-body exercise was linked to fewer fractures, though that evidence is still weak.
• Mix it up over time. Bones may respond better to varied loading than to the same routine forever.
• Check with your doctor first if you have osteoporosis. They can help you choose safe, suitable exercises.

The NHS has more on preventing osteoporosis, including weight-bearing and resistance exercise.

In this short video, Mayo Clinic explains how exercise helps prevent fractures and falls:

What we still don’t know

1. Does brisk walking prevent fractures? Trials big enough to measure broken bones are still needed.
2. Are the walking gains real or inflated? Small trials may have overstated them.
3. What works best for men? Most trials only included women.
4. How should older adults progress? The best way to increase load safely over the years isn’t settled.
5. Does varying your routine help? The idea is plausible, but it hasn’t been properly tested.

My take: walk briskly, and don’t fear exercise

What I like about this study is how practical it is. It moves the question from “does exercise help?” to “what and how much?”

I’m less convinced by the precise rankings. Many trials were small, and the walking results may look better than they really are.

But the big message is sound and cheap. Brisk walking, a couple of strength sessions and some balance work are within reach for most people.

For bones, the best exercise may simply be the one you’ll keep doing every week.