40 Is the New 30 - If You Lift
How Resistance Training Reverses Biological Age
How we age is increasingly becoming something we can influence.
For those in midlife and beyond, one of the most powerful tools available is resistance training. Whether it’s lifting weights or simply using your own bodyweight, consistent strength training has been shown to preserve muscle mass, strengthen bones, regulate metabolism, and even shift biological age markers in a more youthful direction.
It’s not about becoming a bodybuilder. It’s about regaining control over the physical changes that come with age - and protecting long-term health in the process. Encouragingly, this approach aligns with the NHS Long Term Plan’s prevention-first model and is accessible to anyone willing to start with a few simple movements.
What Really Happens as We Age?
From our early 30s onwards, most people experience a gradual decline in muscle mass. Studies suggest that we lose around 3-8% per decade, with the rate of loss increasing after the age of 60. This erosion of muscle - known as sarcopenia - translates into reduced strength, a slower metabolism, and an increased risk of falls and frailty.
Ageing also affects our ability to manage blood sugar. As insulin sensitivity decreases, it becomes easier to store visceral fat around the organs, which raises the risk of developing type 2 diabetes.
Hormonal changes play a significant role too. In men, testosterone levels decline slowly over time. In women, menopause triggers a steep drop in oestrogen, which can accelerate the loss of bone and muscle mass if left unaddressed. Unless counteracted with movement or clinical care, these changes significantly impact physical resilience.
Bone density, often overlooked, also declines without regular loading. Bones are living tissue, and they need stimulus to stay strong. Without it, the risk of osteoporosis increases—especially for postmenopausal women. Meanwhile, mobility and balance can suffer, further raising the risk of injury.
These physiological changes are happening against the backdrop of a concerning trend: two-thirds of adults in England are overweight or obese, with the highest prevalence between ages 55 and 74. This makes preserving muscle not just a matter of strength, but of metabolic and functional protection.
How Lifting Reverses the Ageing Script
The good news? Resistance training addresses all of these issues head-on.
Building and maintaining lean muscle through regular strength training increases resting metabolic rate, which helps manage weight and prevent the common “middle-age spread.” Beyond body composition, research shows that strength training improves blood sugar regulation and lowers HbA1c levels in people with type 2 diabetes. Long-term studies also associate consistent strength training with a reduced risk of developing diabetes in the first place.
When combined with aerobic activity, resistance training becomes even more powerful. Together, they support healthy blood glucose levels, improve cholesterol profiles, and reduce the overall risk of cardiometabolic disease - issues that typically become more pronounced during the 40s and 50s.
There are also significant benefits to bone health. Research like the LIFTMOR trial has shown that even brief, supervised, high-intensity resistance training can improve spinal and hip bone density in postmenopausal women. It’s a clear signal to the skeleton: stay strong, stay resilient.
Strength training also enhances mobility and reduces fall risk. Stronger legs, hips and core muscles contribute to better balance and coordination. Cochrane reviews and large-scale studies have shown that well-designed exercise programmes can reduce falls in older adults by up to a third, and the sooner the habit is established, the better the long-term outcome.
Biological Age: Can Strength Training Turn Back the Clock?
There’s growing interest in how strength training influences biological age - an estimate of how well your body is functioning compared to your actual years.
Unlike chronological age, which counts birthdays, biological age considers a combination of biomarkers, including DNA methylation patterns (known as “epigenetic clocks”), blood markers, and physical fitness.
Emerging research is promising. One study found that just eight weeks of combined aerobic and resistance training reduced biological age by approximately two years in midlife women. Though small, it suggests that lifestyle interventions can measurably affect the body’s ageing trajectory.
Wider population data reinforces this. People who exercise regularly tend to show younger biological profiles across various metrics. Cardiorespiratory fitness, in particular, is associated with “younger” gene expression patterns.
What’s even more fascinating is the discovery of an “epigenetic memory” in muscle. When you strength train, your muscles undergo changes in gene expression that make them more responsive the next time you train. It’s one reason the concept of “muscle memory” is rooted in biology.
While biological ageing is still an evolving science - and different “clocks” don’t always align - the trend is clear. Strength training nudges a wide range of ageing markers in the right direction, from metabolic control to physical function to gene-level adaptations.
Strength Training: The UK’s Forgotten Health Guideline
The UK Government and NHS are actively promoting a shift from reactive treatment to proactive prevention. The NHS Long Term Plan and recent green papers have made it clear: we need to stay well, not just treat illness.
Yet strength training remains the “forgotten guideline.” According to national physical activity recommendations, adults should perform muscle-strengthening activities at least twice a week alongside aerobic exercise. But many people skip this part altogether.
Incorporating strength training into midlife is one of the most accessible, cost-effective ways to align with this prevention-first model - and it pays dividends in later life.
How to Start Strength Training in Your 40s
You don’t need a gym membership or high-end equipment to begin. Two to three strength sessions per week are enough to see benefits. Space them out on non-consecutive days to allow your muscles time to recover and adapt.
Start with movements that target major muscle groups. Think of basic patterns like squatting, hinging at the hips, pushing, pulling, and carrying. Exercises like squats, rows, press-ups, and planks cover these foundations. Use your bodyweight, resistance bands, dumbbells, or machines - whatever you feel safest and most confident with.
Each workout can last 30 to 45 minutes. Perform two to three sets of each movement, aiming for six to twelve repetitions per set. Leave a rep or two in reserve - this ensures you’re working hard without pushing to the point of strain or poor form.
For added bone health, brief bouts of impact - like gentle hops or loaded carries - can be beneficial if your joints tolerate them and your GP gives the go-ahead. This is especially valuable for women around menopause, when bone loss accelerates.
A warm-up is essential. Begin with five to eight minutes of light cardio, such as walking or cycling, then add dynamic movements to prepare the hips, spine and shoulders. This supports joint mobility and primes the body for safer lifting.
There are also important red flags to watch for. Sharp, localised pain - especially in the joints - is a signal to stop. If you live with osteoporosis, have a history of fractures, or experience cardiovascular or metabolic issues, speak to your GP before starting. With professional oversight, even heavier resistance training can be safe and effective - as the LIFTMOR trial demonstrated.
Nutrition Matters Too
What you eat supports how you train. Protein is especially important when building or maintaining muscle. Aim to include high-quality protein at each meal - sources like eggs, dairy, legumes, fish or lean meats.
While the UK’s standard recommendation is 0.75 grams of protein per kilogram of body weight per day, many experts suggest that active older adults aim for closer to 1.0 - 1.2g/kg daily to support muscle retention.
Staying hydrated, prioritising whole foods, and getting adequate sleep will all improve your recovery and performance.
Closing thoughts
The physical decline we associate with ageing isn’t fixed. Muscle responds to stimulus - at any age.
Just a few strength-focused sessions each week can help rebuild lost muscle, improve balance, preserve bone density, and reduce biological age markers. It also supports healthy weight, blood sugar, and long-term independence.
You don’t need a radical lifestyle overhaul or endless hours in the gym. Start small. Stay consistent. Your body will thank you - not just this year, but for decades to come.
