Just 90 to 120 minutes of strength training a week may deliver some of the largest long-term health benefits of any exercise type, according to a study that tracked more than 147,000 adults over 30 years. The findings suggest the minimum effective dose of resistance exercise is far lower than many people assume, and that adding muscle-building activity to a weekly routine produces measurable gains in health outcomes even at modest volumes.

The study followed participants across three decades, tracking their exercise habits alongside health outcomes including cardiovascular disease, diabetes, all-cause mortality and functional decline in later life. People who did one to two hours of strength training per week showed significantly better outcomes on most measures compared to those who did no resistance exercise, even when researchers controlled for other health behaviours including aerobic exercise and diet.

The sweet spot appeared to be between 90 and 120 minutes weekly — roughly two sessions of 45 to 60 minutes, or three shorter sessions. Above that threshold, additional strength training continued to produce benefits but at a diminishing rate. Below it, the gains were still present but smaller. The findings challenge both the idea that strength training requires significant time investment and the assumption that more is always better.

Strength training — also called resistance training — covers a range of activities from weightlifting and machine-based gym exercises to resistance bands, bodyweight movements such as press-ups and squats, and carrying heavy loads. All of these formats produced similar benefits in the study when matched for intensity and duration, suggesting the specific equipment or setting matters less than the act of loading muscles against resistance.

The health benefits identified in the study are wide-ranging. Participants who met the 90 to 120 minute weekly threshold showed lower rates of type 2 diabetes and cardiovascular disease, better bone density in later life, reduced rates of functional impairment after age 70, and lower all-cause mortality. The benefits were present across age groups and both sexes, though the magnitude was somewhat larger in women and in older adults starting from a lower baseline of physical capacity.

Public health guidelines from many governments currently recommend 150 minutes of aerobic activity per week alongside two sessions of muscle-strengthening exercises. The new findings suggest the muscle-strengthening component may deliver outsized returns relative to the time invested, and that people who currently do no resistance exercise would benefit from even a modest amount of it. Researchers said the findings should be used to encourage people who feel time-poor rather than to suggest that more exercise is unnecessary.

ScienceDaily described the study as one of the largest and longest-running analyses of strength training and health outcomes ever conducted. The research team called for updated public health messaging that makes the minimal effective dose of resistance exercise clearer, noting that current messaging often emphasises aerobic activity to the point where many people underestimate the value of strength training as a standalone investment in long-term health.