- Bone is living tissue that strengthens in response to load and impact.
- Peak bone mass is reached around your late twenties to early thirties, then slowly declines.
- Progressive, reasonably heavy lifting and some impact work help most.
- Calcium, vitamin D and protein support the effect of training.
Bone is living tissue
It is easy to think of the skeleton as a fixed frame, but bone is constantly being broken down and rebuilt. When bones experience loads greater than they are used to, cells within the bone sense the strain and trigger remodelling that makes the bone stronger. When loading is low, as in long periods of bed rest, bone is gradually lost.
Most people reach their peak bone mass around their late twenties to early thirties. After that, bone density slowly declines, and for women the rate speeds up for several years around menopause as oestrogen falls. Osteoporosis, where bones become weaker and more likely to break, affects millions of people in the UK, and many do not know they have it until a fracture. Wrist, spine and hip fractures are the most common results, and hip fractures in particular can have a big impact on independence.
Men are affected too, usually later in life, and risk rises for anyone who has taken long courses of steroid tablets, has a low body weight or has a family history of hip fracture.
What kind of loading helps bone
Bone responds best to loads that are relatively high, applied quickly, varied in direction and different from what it is used to. That is why walking, while excellent for general health, does relatively little for bone density in most adults: the skeleton is already accustomed to it.
The most useful forms of loading are:
- Progressive resistance training: squats, deadlifts, lunges, presses and rows that gradually get heavier.
- Impact: jumping, hopping, skipping and running, introduced gradually.
- Varied direction: side steps, lateral hops and multi-directional movements that load bone in new ways.
Muscles pulling on bone are a significant load in their own right, which is why strength training helps even without impact. Swimming and cycling are brilliant for fitness but do little for bone because they are not weight bearing, so if they are your main exercise, adding strength work is particularly worthwhile.
How heavy should you go?
Bone appears to respond better to moderately heavy loading than to light weights for lots of reps. Supervised studies of progressive heavy lifting and impact training in postmenopausal women with low bone mass have reported improvements in bone density and physical function without the injury problems many people would expect. This is part of why guidance has moved away from telling people with low bone density to avoid lifting.
For most people, this means building up over weeks to sets of around 5 to 8 reps with a weight that is genuinely challenging, on big compound movements, at least twice a week. Start lighter, learn technique and progress gradually. Heavy lifting does not mean reckless lifting.
A typical week might include two full body strength sessions built around a squat or leg press, a hinge such as a Romanian or trap bar deadlift, a push, a pull and a carry, plus a few minutes of jumping or skipping on two or three days if that suits your joints.
Because bone adapts slowly, changes in density take months to years to show up on a scan. Treat this as a long-term habit rather than a quick fix.
If you have osteopenia or osteoporosis
If you have been diagnosed with low bone density, exercise is still recommended, and strength training is a central part of it. UK bone health guidance encourages people with osteoporosis to stay active, build strength and balance, and progress sensibly. It may suggest some care with repeated, heavily loaded forward bending and twisting of the spine, particularly if you have had spinal fractures.
It is sensible to get advice from your GP or a physiotherapist before starting, particularly if you have had fractures. A physio can help design a programme that loads bone effectively while respecting any limitations. Balance training matters too, because avoiding falls is just as important as stronger bones in preventing fractures. Carries, step-ups and supported single leg work build strength and balance together.
Food, vitamin D and lifestyle
Training works best when bones have the raw materials they need:
- Calcium: dairy, fortified plant milks, tinned fish with soft bones, calcium-set tofu and green vegetables.
- Vitamin D: the NHS advises most people in the UK to consider a daily 10 microgram supplement in autumn and winter, when sunlight is too weak for the skin to make enough, and some groups year round. See our guide to vitamin D in the UK.
- Protein: adequate protein supports both muscle and bone.
- Enough energy overall: very low calorie diets and low energy availability can harm bone, especially in young women and endurance athletes.
Smoking and heavy drinking both harm bone health, and cutting back on either helps.
Start at any age
Building bone in youth creates reserves for later life, which is one reason strength training and sport are so valuable for teenagers and young adults. But it is never too late. Older adults can improve bone density modestly and, more importantly, reduce their risk of falls and fractures through stronger muscles and better balance. Consistency matters more than any single session.
It is also worth knowing your risk. If you have broken a bone in a minor fall, have taken long-term steroids or have a strong family history, ask your GP whether a bone density scan is appropriate.
For practical starting points, see strength training over 50 and strength training for women. If you have a diagnosis and want guidance on loading safely, Lycan Strength's on-site physiotherapy can assess you and build a plan, with 20% off for members.
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Questions
Can strength training reverse osteoporosis?
It can modestly improve bone density in some people and, importantly, lowers fracture risk by improving strength and balance. It works best alongside any medical treatment you have been prescribed.
Is walking enough for bone health?
Walking is great for general health, but it adds relatively little stimulus for bone in most adults. Adding strength training and some impact is more effective.
Is it safe to lift weights with low bone density?
For most people, yes, with sensible progression and guidance. Get advice from your GP or a physiotherapist first, especially if you have had fractures.
How often should I train for bone health?
Aim for strength training on at least two days a week, plus some impact on a few days if your joints tolerate it.
General guidance for healthy adults. If you have a medical condition, injury or are pregnant, check with a health professional before changing your training or diet.