How to prevent muscle loss after 40: strength, protein and the habits that matter

The best way to prevent muscle loss after 40 is strength training two or three times a week, hard enough that the last reps are tough and a little heavier over time, with enough protein spread across your meals. Walking, sleep and losing weight slowly help too, but no habit replaces asking your muscles to work against resistance.

Below: how much muscle people lose with age and why, two simple tests you can do at home, the strength routine that works, how much protein to aim for (with a table by body weight and foods), what changes around menopause, how to protect muscle while losing weight, a 4-week start, and when weakness is a reason to see a doctor.

How much muscle do you lose after 40?

Muscle mass starts to fall slowly from around your 30s. A widely cited review (Volpi and others, 2004) puts the loss at roughly 3–8% per decade after age 30, speeding up after 60. Strength falls faster than size, because the nerves that drive muscle and the fast-twitch fibers that produce power decline too.

Those are averages across people who mostly don't strength train. They aren't a fixed timetable. How much you lose depends a great deal on how much you use your muscles, how much you eat, illness, injury and time spent in bed. When age-related loss of muscle and strength becomes large enough to affect daily life, doctors call it sarcopenia.

Why it happens

• Using muscles less. Many of us sit more, carry less and climb fewer stairs as life changes. Muscle you don't use is muscle your body stops keeping.
• Muscles respond less to food. Older muscle needs a bigger dose of protein at a meal to switch on the same amount of building, which is why protein targets for older adults are higher.
• Hormones. For women, falling estrogen around menopause is linked to faster loss of muscle and strength. A Finnish study following women through the menopause transition (Juppi and others, 2020) found lean and muscle mass fell over that time, and that more physically active women held on to more.
• Illness and bed rest. A week or two in bed or in hospital can cost a surprising amount of leg strength in older adults. Getting moving again soon, as your doctor allows, matters.
• Losing weight fast. Part of the weight lost on a diet is muscle, unless you're also strength training and eating enough protein.

Two tests you can do at home

The European Working Group on Sarcopenia (EWGSOP2, 2019) puts low muscle strength first when screening for sarcopenia, and suggests two simple strength tests. You can do one of them at home today and use it to track your progress.

Most women in their 40s and 50s will be well inside these numbers. That's fine: the point is to know your starting time and watch it fall as you train. If you're over the cut-off, or getting up from a chair is a struggle, mention it to your doctor; it's worth checking and it's very trainable.

Strength training: the one habit that rebuilds muscle

Strength training is the most proven way to keep and rebuild muscle at any age. It's never too late: in a well-known study (Fiatarone and others, JAMA, 1990), ten frail nursing home residents aged 86 to 96 did eight weeks of high-intensity leg training and their leg strength rose by an average of 174%.

Here is what the research and the guidelines point to:

"Toning" with very light weights for dozens of reps does little if the sets never get hard. Neither does a class where you move constantly but never lift anything heavy for your size. What counts is that the last few reps of a set are a real effort.

A home routine that covers everything

Six movements, each with a version for home:

No weights? You can start with body weight, bands and filled water jugs: see strength training without weights or our resistance band workout. For a full schedule with weights, see the 12-week strength training plan for women over 40.

How much protein you need to keep muscle

The US Recommended Dietary Allowance for protein is 0.8 g per kg of body weight a day, set as a minimum for most adults. Experts on aging muscle advise more. The PROT-AGE study group (Bauer and others, 2013) recommends 1.0–1.2 g per kg a day for adults over 65, and more for those who are active or ill. For people who strength train, a 2018 meta-analysis (Morton and others, British Journal of Sports Medicine) found extra protein helped muscle gains up to about 1.6 g per kg a day, with little benefit above that.

So a reasonable range for a woman over 40 who strength trains is about 1.2–1.6 g per kg of body weight a day:

If you're carrying a lot of extra weight, base the number on a healthy weight for your height rather than your current weight. If you have kidney disease, ask your doctor before raising your protein.

Spread it over the day

Many people eat little protein at breakfast and most at dinner. PROT-AGE suggests about 25–30 g of protein per meal for older adults, since muscle responds better to a good dose several times a day than to one big one. Some everyday sources, approximately (USDA FoodData Central; check your labels):

A breakfast of Greek yogurt with a couple of eggs, or a cottage cheese bowl, gets you most of the way to 25–30 g. A protein shake is fine on busy days but not required.

What changes around menopause

The years around menopause are a time many women notice they're weaker, softer around the middle, or slower to recover. Falling estrogen plays a part, along with worse sleep and often less activity. The answer isn't a special workout. It's the same strength training, done steadily, with protein and sleep looked after. Research on the menopause transition suggests women who stay active keep more of their muscle.

Menopausal hormone therapy is a medical decision with its own benefits and risks; it isn't prescribed to build muscle. If symptoms are getting in the way of training, talk to your doctor about your options. Bone density falls in the same years, and strength training helps there too: see bone density exercises for women over 50 for the impact work to add.

Losing weight without losing muscle

Some of the weight lost on a diet alone is muscle. Reviews of weight loss in older adults (Weinheimer and others, 2010) found that adding exercise, especially strength training, reduces how much lean mass is lost. To lose fat and keep muscle:

• Lose slowly. Aim for about 0.5–1% of your body weight a week rather than a crash diet.
• Keep lifting. Strength training through a weight loss tells your body the muscle is still needed.
• Keep protein high. The upper end of the table above while you're eating less.
• Track strength, not just the scale. If your lifts or chair-stand time get worse, you're losing too fast.

If you're losing weight on a prescribed weight-loss medication, these points matter even more; ask your prescriber about protein and exercise alongside it.

Other habits that help

• Walk and move most days. Walking doesn't build much muscle on its own, but moving often keeps the muscle you have in use and supports your heart. The guidelines ask for 150–300 minutes of moderate activity a week.
• Sit less. Break up long sitting with a few minutes on your feet every hour; get up from your chair without using your hands when you can.
• Sleep 7 hours or more. The CDC recommends at least 7 hours a night for adults. Poor sleep makes training harder and recovery slower.
• Go easy on alcohol. Heavy drinking is linked to muscle weakness, and alcohol disturbs sleep.
• Vitamin D. Low vitamin D is linked to weak muscles. If you're at risk (little sun, darker skin, older age), ask your doctor about testing rather than guessing a dose.
• Creatine, if you want to. Reviews of trials in older adults (Chilibeck and others, 2017) found creatine taken alongside strength training gave slightly larger gains in muscle and strength than training alone. It's optional and only helps alongside training; ask your doctor first if you have kidney problems.

A 4-week start

Then keep going. Muscle is built and kept over months and years, and what matters most is that you're still training next year. If you'd like the first weeks laid out in more detail, see how to start strength training at 50.

When weakness is a reason to see a doctor

Gradual loss of strength with age is common and trainable. See your doctor if weakness comes on quickly over weeks, is in one arm or leg, comes with weight loss you can't explain, muscle pain, fever, falls, or trouble swallowing, or started after a new medicine. Get urgent help for sudden weakness on one side of the body. Also check with your doctor before starting strength training if you have heart disease, uncontrolled blood pressure, chest pain or dizziness when active, or a recent operation.

Questions people ask

Can you regain muscle after 40 or 50?

Yes. People gain muscle and strength from strength training into their 80s and 90s. Progress is usually quickest in the first months for someone who hasn't trained before.

Is walking enough to prevent muscle loss?

Walking is good for your heart and keeps you moving, but it doesn't load the muscles enough to build them for most people. Add strength training at least twice a week.

What is the best exercise to prevent muscle loss?

No single exercise. A routine that trains legs, hips, back, chest and arms with enough weight to make the last reps hard, two or three times a week. If you could only pick one, squats or sit-to-stands train the muscles you most need to stay independent.

Does menopause cause muscle loss?

Falling estrogen is linked to faster loss of muscle and strength, alongside age and less activity. Strength training and enough protein help women keep muscle through those years.

How much protein should a woman over 40 eat to keep muscle?

For a woman who strength trains, about 1.2–1.6 g per kg of body weight a day, in 25–30 g doses at meals, is a range many researchers support. Check with your doctor if you have kidney disease.

More plain guides on getting stronger at home: all our home strength guides, including bone density exercises for women over 50.

Sources: Volpi E., Nazemi R., Fujita S., "Muscle tissue changes with aging", Current Opinion in Clinical Nutrition and Metabolic Care, 2004. Cruz-Jentoft A. et al., "Sarcopenia: revised European consensus on definition and diagnosis" (EWGSOP2), Age and Ageing, 2019. Fiatarone M. et al., "High-intensity strength training in nonagenarians", JAMA, 1990. Bauer J. et al., "Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group", JAMDA, 2013. Morton R. et al., "A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults", British Journal of Sports Medicine, 2018. Juppi H. et al., "Role of menopausal transition and physical activity in loss of lean and muscle mass", Journal of Clinical Medicine, 2020. Weinheimer E., Sands L., Campbell W., "A systematic review of the separate and combined effects of energy restriction and exercise on fat-free mass in middle-aged and older adults", Nutrition Reviews, 2010. Chilibeck P. et al., "Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis", Open Access Journal of Sports Medicine, 2017. US Department of Health and Human Services, Physical Activity Guidelines for Americans, 2nd edition, 2018. USDA FoodData Central. CDC, How much sleep do I need. This guide is about exercise and eating habits and is not medical advice; follow your doctor's advice where it differs.