What strength training does for your bones after 40

by Rosie Stockley · Strong for Life

When fitness comes up in conversations about midlife, the focus tends to fall on energy, sleep, and how the body feels from one week to the next. Bone density rarely enters the picture, partly because you can't feel it changing, and partly because it's associated in most people's minds with something that happens much later in life.

The decline in bone density, though, starts earlier than most women realise, and the window for doing something meaningful about it is now.

Why bone density matters in your 40s

Bone is living tissue, and throughout your life it's constantly being broken down and rebuilt. In your younger years, the rebuilding process keeps pace with the breakdown, but from your late 30s onwards, and significantly more during perimenopause, that balance starts to shift.

Oestrogen plays a central role in regulating bone turnover. When oestrogen levels begin to fluctuate and decline during perimenopause, the rate of bone breakdown accelerates. Women can lose up to 20% of their bone density in the five to seven years around the menopause transition, and the long-term consequence is an increased risk of osteoporosis and fracture - roughly one in two women over 50 will experience an osteoporosis-related fracture in their lifetime.

This isn't meant to be alarming - it's meant to be useful, because the research on what you can do about it is encouraging.

What the evidence says

The type of exercise matters significantly when it comes to bone density, and the reason comes down to how bone responds to load. Activities that create significant impact or load on the skeleton stimulate bone-forming cells, called osteoblasts, to lay down new bone tissue.

Strength training is one of the most consistently effective interventions for bone density in women in midlife and beyond. A 2025 systematic review and meta-analysis of 17 randomised controlled trials found that resistance training produced significant improvements in bone mineral density at both the lumbar spine and femoral neck in postmenopausal women - two of the sites most vulnerable to osteoporosis-related fracture. The exercises with the most impact are those that load the spine and hips directly: squats, deadlifts, lunges, loaded carries, and upper body pressing and pulling movements.

The research also shows that bone responds specifically to the type of stress placed on it, which is why walking, while valuable for many reasons, isn't sufficient on its own to protect bone density. It loads the skeleton, but not with enough variation or intensity to drive meaningful bone adaptation, whereas strength training does.

How much is enough

You don't need to be lifting heavy weights to see a benefit, though progressive load does matter over time. Studies consistently show that two to three sessions of resistance training per week, done consistently over months and years, is enough to make a meaningful difference to bone density outcomes.

Current ACSM guidelines recommend strength training at least twice a week for adults - and the evidence for women in midlife specifically is strong enough that these guidelines treat it as essential, not optional. Two sessions a week is a sufficient and evidence-backed starting point.

The key is consistency and progression. Your bones adapt to load over time, so gradually increasing the challenge of your training, whether that means adding weight, reps, or complexity, is what drives continued adaptation.

The longer view

There's something I find motivating about training for bone health, which is how clearly it connects what you do now to how you feel and function twenty or thirty years from now. Bone density you build and protect in your 40s is bone density that reduces your fracture risk at 70 and 80 - and it's one of the clearest examples of training for the long game rather than the immediate result.

If you want to train in a way that's built around exactly this - progressive, structured, and designed for women in midlife - Strong for Life might be a good fit. Find out more at www.strongforlifewithrosie.com

2025 systematic review and meta-analysis, 17 RCTs (Journal of Orthopaedic Surgery and Research): pubmed.ncbi.nlm.nih.gov/40420105