Strength and independence: why it matters and how much is enough to start

What is lost over the years, and how fast

An analysis of twelve British studies with almost 50,000 people described grip strength — measured by squeezing a dynamometer with your hand — across the life course: it rises until early adulthood, holds steady until midlife and declines from then on. The highest median was 51 kg (about 112 lb) in men, between ages 29 and 39, and 31 kg (about 68 lb) in women, between 26 and 42.⁴

Between ages 30 and 80, the median drops by a little under 40% in both sexes (our calculation from those figures). Studies that follow the same people over years give similar or higher rates of loss in old age: around age 75, strength was lost at 3–4% a year in men and 2.5–3% in women, while muscle mass was lost at less than 1% a year.⁵

That's why losing muscle and losing strength are treated as different things. In the studies that measured both in the same people, strength declined two to five times faster than muscle mass, and its loss is a more consistent risk factor for disability and death than the loss of muscle.⁵ Power — strength applied quickly — declines earlier and faster than strength.⁵⁶ In studies of older people, many of them with mobility limitations, leg power was somewhat more closely related than strength to how long it took them to get up from a chair, climb stairs or walk.⁶

You may have heard the word sarcopenia. The 2019 European consensus defines it as a progressive and generalized muscle disorder associated with more falls, fractures, physical disability and mortality, and puts low strength, not loss of mass, at the center of its definition, because strength is currently the most reliable measure of muscle function.⁷ Assessing it is a job for a health professional; this article doesn't go into criteria or tests.

Why it matters day to day

According to the US physical activity guidelines, being active makes it easier for older adults to carry out activities of daily living — eating, bathing, dressing, getting in and out of bed or a chair, moving around the house or the neighborhood — and can help them keep their mobility and independence for longer.² Leg weakness in particular is associated, in older people, with slower walking, a higher risk of disability and more falls.⁹

Strength also shows up in large population studies. In the PURE study, with about 140,000 people aged 35 to 70 from 17 countries followed for a median of four years, every 5 kg (11 lb) less grip strength was associated with a 16% higher risk of death from any cause, and with more heart attacks and strokes. It was not associated with more fall-related injuries or more fractures.⁸

What training trials achieve

The Cochrane review of strength training in older people pooled 121 randomized trials with 6,700 people aged 60 or older. In most of them, people trained two or three times a week against a demanding resistance that was increased as they got stronger.⁹ Compared with control groups:

Strength can be gained past 75, too. A review of 22 randomized trials found a clear effect on strength, including in the group aged 80 or older, and a small increase in muscle size.¹⁰

How much it takes to get started

The WHO recommends that all adults, including those aged 65 and older, do muscle-strengthening exercises of moderate or greater intensity that work all the major muscle groups, two or more days a week.¹ The US guidelines list them: legs, hips, back, abdomen, chest, shoulders and arms.²

From age 65, the WHO and Spain's Ministerio de Sanidad add multicomponent physical activity — varied and focused on strength and functional balance — three or more days a week, to improve functional capacity and prevent falls.¹³ In 2020 the WHO extended this recommendation to all older people, not only those with poor mobility.¹

Is more better? It isn't clear. In a meta-analysis of 16 cohort studies, doing strength exercises was associated with a 10% to 17% lower risk of mortality and of some major chronic diseases. The largest associated reduction was at around 30–60 minutes a week, and the effect of much larger volumes was uncertain.¹¹ The WHO, for its part, found no evidence that higher volumes of strength training provide additional benefit.¹

If what's holding you back is time, in the minimums that count when you're short on time we explain that a single set per exercise is enough to start gaining strength. And strength doesn't replace aerobic activity: the recommendation is to do both,¹ so walking still counts; what the studies say about how many steps a day make sense is covered separately. For the aerobic part, we also explain how to recognize moderate intensity without a device.

Getting started and progressing without overcomplicating it

Any activity in which your muscles work against resistance with moderate to high effort counts as strength exercise: lifting weights, using resistance bands, doing bodyweight exercises such as push-ups, or pushing, pulling, carrying and lifting heavy things, including climbing stairs.³² None of those examples requires a gym.

To progress, the guidelines agree: start small and increase gradually.²³ For someone starting from zero, the US guidelines suggest beginning with one day a week at light or moderate effort, moving over time to two days, and raising the intensity a little each week until it's moderate or greater.² In the trials, progressing meant increasing the resistance as people got stronger.⁹ What follows is our reading of the sources, not a prescription:

• Pick a few exercises that, between them, work your legs, trunk and arms, and aim to do them two days a week.
• Look for an effort that's challenging but still lets you do the movement properly from start to finish.
• When an exercise gets easy, make it a bit harder: more repetitions, a little more weight or a more demanding variation.
• Tie the session to a fixed time in your week; in the habits guide we explain how to decide when and where to do it.
• Some muscle soreness in the first few days is normal; pain that doesn't go away with rest is a reason to stop and get it checked.