Benefits of Strength Training: What the Research Shows

Strength training does a lot more than build bigger muscles. Lifting weights, using resistance bands or doing bodyweight exercises is linked to a longer life, lower risk of several diseases, better mood and an easier time with everyday tasks. It has limits, too, so we separate what the studies show from what they don't.

It keeps you strong and independent

The most direct benefit is the one you'd expect. A Cochrane review of 121 trials with about 6,700 older adults found that resistance training had a large effect on muscle strength, a small but significant improvement in physical function, a modest improvement in gait speed and a moderate-to-large improvement in getting out of a chair.² The CDC adds that strength training helps adults build or keep muscle and strength, and protects bones, joints and muscles as we age.⁵

Lower risk of disease and early death

Most of this evidence comes from cohort studies, which follow large groups of people over time. A meta-analysis of 16 of them found that strength training was linked to roughly 10–17% lower risk of death from any cause, heart disease and type 2 diabetes. It was also linked to lower risk of cancer overall and of lung cancer, but not of colon, kidney, bladder or pancreatic cancer.¹

Another pooled analysis of 80,306 adults in England and Scotland found that any strength-promoting exercise was associated with 23% lower all-cause mortality and 31% lower cancer mortality. Adults who met both the aerobic and the strength guidelines had 29% lower all-cause mortality.⁶

The good news? You don't need hours of it. In the meta-analysis, the biggest risk reduction (about 10–20% for death from any cause, heart disease and cancer overall) showed up at roughly 30–60 minutes of strength training a week. For diabetes, the benefit kept growing up to about 60 minutes a week.¹

Blood pressure and blood sugar: some effects, with limits

Blood pressure. A meta-analysis of 28 randomized trials with 1,012 participants found that resistance training lowered systolic and diastolic blood pressure by about 3.9 mm Hg in groups with normal or borderline-high blood pressure. In the five groups of people with high blood pressure, the drops weren't statistically significant. The trials also found no significant effect on fasting blood sugar or most blood lipids, although triglycerides fell slightly.⁷

Type 2 diabetes. A meta-analysis of 20 studies with 1,172 adults with type 2 diabetes found that resistance training lowered HbA1c (a measure of average blood sugar) by about 0.4 percentage points compared with controls. Larger gains in strength were associated with larger reductions, and the effect was not significantly different from aerobic training. Results varied a lot between studies.⁸

Mood and thinking

Depression. A meta-analysis of 33 randomized trials with 1,877 participants found that resistance training reduced depressive symptoms, with a moderate average effect. The studies varied a lot, and better-blinded trials showed smaller drops, so the authors called for higher-quality research.³

Cognition. A meta-analysis of 24 studies found positive effects of resistance exercise on cognition overall, including overall cognitive scores and executive functions (planning and mental flexibility), but not on working memory. Results varied widely between studies.⁹

Bones: small changes, possibly protective

The evidence for bones is more modest. A meta-analysis of 7 studies with 370 older adults found small changes in bone mineral density with resistance training: about +0.6% at the hip and the spine and about −0.2% at the femoral neck. The authors concluded that this suggests, at most, a preventive effect against fragile bones.¹⁰ Think of strength training as one piece of bone health, not a treatment for osteoporosis on its own.

Sarcopenia: the main treatment

For age-related muscle loss, international clinical guidelines strongly recommend resistance-based exercise as the main treatment.¹¹ We explain the condition in What Is Sarcopenia? and why muscle matters in Muscle Is an Organ: What It Needs to Survive.

What the evidence can't tell us

• Many results come from observational studies and can't prove cause and effect.
• Results vary a lot between trials. Several of the meta-analyses above report high heterogeneity.
• Not every outcome improves. For example, blood pressure didn't drop significantly in people with high blood pressure, and most cancers weren't linked to strength training.
• Safety data are incomplete. In the Cochrane review of older adults, adverse events were poorly recorded: joint pain and muscle soreness were reported in many studies that tracked them, and serious events were rare.²

How much do you need?

The U.S. guidelines recommend strength training on at least 2 days a week, on top of aerobic activity.⁴ In one pooled analysis, adults who met both guidelines had the lowest mortality (a hazard ratio of 0.71, compared with 0.84 for aerobic activity alone).⁶ We cover the full weekly picture in How Much Exercise Do Adults Need? The U.S. Guidelines.

Frequently asked questions

Does strength training lower the risk of dying?

In large studies that followed people for years, it was linked to roughly 10–17% lower risk of death from any cause.¹ Because the studies are observational, they show a link, not proof of cause and effect.

Is strength training better than cardio?

It's not either-or: the guidelines recommend both. In one pooled analysis, adults who met both the aerobic and the strength guidelines had lower mortality than those who met only the aerobic one.⁶

Can strength training help with depression?

A meta-analysis of randomized trials found that resistance training reduced depressive symptoms, though the studies varied and the authors asked for better-designed trials.³ It isn't a replacement for professional care.

Is it safe for older adults?

Generally, yes. Serious problems were rare in a Cochrane review of older adults, but muscle soreness and joint pain were common in the studies that tracked them.² Start gradually, and get guidance if you have a health condition.

The bottom line

Strength training is linked to stronger muscles, better function as you age, lower risk of several chronic diseases and a better mood. Some benefits have stronger evidence than others, and some effects are small. Two days a week, on top of aerobic activity, is the guideline minimum.

The images in this article were created with AI tools to illustrate concepts. They are not exact anatomical depictions or scientific evidence.