Muscle is metabolic capital: why strength matters at every age
If one habit could support your metabolism, your independence, and how long you live, building and keeping lean muscle would be near the top of the list. Muscle is not just for strength or appearance. It is one of the most active and protective tissues in the body.
Muscle drives your resting metabolism. Roughly 60 to 75 percent of the calories you burn each day are used at rest, just to keep your heart beating, your brain working, and your cells running (Ravussin and Dulloo, 2022). The biggest factor in that resting burn is your fat-free mass, the lean tissue that includes muscle. It accounts for roughly 70 to 75 percent of the difference in resting metabolic rate between people (Stubbs et al., European Journal of Clinical Nutrition, 2018; Tran et al., Experimental & Molecular Medicine, 2022). Fat tissue contributes only about 3 to 5 percent of resting energy use (Ravussin and Dulloo, 2022). Build and keep muscle, and your baseline stays higher, even while you sleep. Lose it, and that baseline falls.
Muscle loss sneaks up on us. Muscle peaks around age 20 to 30. Between 40 and 70 it drops by roughly 8 percent per decade, and after 70 the losses speed up to nearly 10 percent per decade (Duan et al., Scientific Reports, 2025). This age-related loss, called sarcopenia, raises the risk of falls, fractures, disability, hospitalization, and death. Resistance (strength) training is the only non-drug approach shown to build and maintain muscle mass, strength, and power across the lifespan, and it is never too late to start (Fyfe et al., Sports Medicine, 2022).
Muscle and living longer. A meta-analysis of 56 studies and more than 42,000 people found that sarcopenia roughly doubled the risk of death (Xu et al., Gerontology, 2021). In older adults, functional sarcopenia was also linked to a higher risk of cardiovascular disease and death from any cause (Jeong et al., Scientific Reports, 2026). Any resistance training was associated with a 15 percent lower risk of death from any cause, 19 percent lower risk of cardiovascular death, and 14 percent lower risk of cancer death (Shailendra et al., American Journal of Preventive Medicine, 2022). A study following nearly 150,000 people for up to 30 years linked about 90 to 120 minutes of resistance training per week to a 13 percent lower risk of death, even after accounting for aerobic exercise (Zhang et al., British Journal of Sports Medicine, 2026). The lowest risk appears in people who do both strength and aerobic exercise (Gould et al., Cochrane Database of Systematic Reviews, 2022).
More is not always better. Benefits tend to level off at a moderate dose, roughly 60 to 120 minutes per week, and extra hours add little. The goal is consistency, not extremes.
More than calories. Resistance training also improves blood sugar control and insulin sensitivity, lowers blood pressure, strengthens bones, eases anxiety and depressive symptoms, and improves balance and function that help prevent falls (Fyfe et al., 2022; Gould et al., 2022).
Putting it into practice. Global guidelines recommend muscle-strengthening activity on at least two days per week, on top of regular aerobic activity. Train all the major muscle groups: legs, hips, back, chest, abdomen, shoulders, and arms. Use enough resistance to be challenging, whether that is bodyweight, bands, free weights, or machines. Pair it with walking, cycling, or swimming, and make protein and consistency a priority.
The bottom line. Lean muscle keeps your resting metabolism higher, protects your heart and bones, preserves your independence as you age, and is consistently linked to living longer. Strength training a couple of times a week is a modest habit with an outsized return.
This article is for general education and is not a substitute for personalized medical advice. Talk with your healthcare provider before beginning a new exercise program, especially if you have existing health conditions.