Why 90 minutes of weight training a week could be enough for boosting longevity

Before hitting the gym today or trying another exercise for your fitness journey, you must know what this new research has come up with.

A new study published in the British Journal of Sports Medicine suggests that around 90 to 120 minutes of strength or resistance training each week may be the ideal range for promoting longevity. Drawing on nearly three decades of data from more than 1.47 lakh adults, researchers found that moderate resistance training was associated with a lower risk of death from all causes, cardiovascular disease and neurological diseases. 

Considering that cardiovascular diseases remain the leading cause of death worldwide and that physical inactivity is a major risk factor for several chronic conditions, the findings may offer further evidence that relatively modest amounts of strength training could contribute to healthier ageing and longer life. 

How much strength training is enough?

Researchers analysed data from three large prospective cohorts - the Health Professionals Follow-up Study, Nurses' Health Study and Nurses' Health Study II. Weekly resistance training and aerobic activity were assessed using validated questionnaires and updated every two years. 

Overall, the study included 147,374 participants - 31,540 men and 1,15,834 women - and followed them for up to 30 years. During this period, researchers documented 35,798 deaths. 

"Compared with no resistance training, 90–119 min/week of resistance training was associated with a 13% lower risk of all-cause mortality, 19% lower risk of cardiovascular mortality and 27% lower risk of neurological disease mortality, adjusting for aerobic activity. No additional benefit was observed above 120 min/week," the researchers wrote. 

Reduced cancer mortality, however, appeared only at lower levels of resistance training. Participants performing one to 29 minutes weekly had a 9 per cent lower risk, while those exercising 30 to 59 minutes had a 12 per cent lower risk compared with people who did no strength training. 

Joint analyses showed that the lowest mortality risk was observed among people who combined resistance training with high levels of aerobic activity. 

"Compared with those with inadequate aerobic activity and no resistance training, mortality risk was lowest among participants with both high aerobic and resistance training," the researchers noted. 

Why combining weights and cardio may matter

According to the researchers, their findings are consistent with previous meta-analyses showing that any resistance training is linked to roughly a 15 per cent lower risk of all-cause mortality. 

The association with cardiovascular mortality also aligned with most earlier studies. The authors suggested that long-term resistance training may help improve arterial stiffness, a known predictor of cardiovascular events, especially when combined with aerobic exercise. 

"Our joint analyses showed that resistance training combined with >7.5 MET-hours/week of aerobic activity was consistently associated with lower CVD mortality," they wrote. 

The study also found a significant inverse association between resistance training and neurological disease mortality. Most neurological deaths in the cohorts were due to dementia. 

Randomised controlled trials have previously suggested that resistance training may induce structural changes in the brain that could potentially slow the development or progression of Alzheimer's disease. 

However, the researchers urged caution. 

"Reverse causation remains possible, given the decades-long prodromal stage of neurodegenerative diseases like Alzheimer's, and there is a progressive reduction in physical activities long before dementia is diagnosed," they wrote. 

The authors also noted that aerobic activity alone appeared to provide greater benefits than resistance training alone, but the combination of both offered the greatest reduction in mortality risk. 

"Aerobic exercise is generally linked to improved hemodynamics, lipid profiles and cardiorespiratory fitness, whereas resistance training may improve glucose metabolism, body composition and muscular strength," they explained. 

Overall, the researchers concluded that moderate long-term resistance training - around 60 to 119 minutes per week - was associated with lower mortality in both men and women, with benefits plateauing at approximately 120 minutes per week. 

Limitations to consider

The authors acknowledged several limitations. First, resistance training was self-reported, making measurement errors unavoidable. Nevertheless, repeated assessments over decades and validated questionnaires likely reduced inaccuracies. 

"Our study has several limitations. First, measurement error was inevitable as resistance training was self-reported. However, the use of validated questionnaires and cumulative averages from repeated assessments likely reduced this error compared with studies relying on a single baseline measurement," they wrote. 

The questionnaires recorded hours per week but did not capture intensity, load, repetitions, rest periods or other forms of strength training such as Pilates and calisthenics.

"It is possible that the health effect of resistance training may differ by intensity, and we could not assess this dimension as intensity data were not collected," the researchers noted. 

Another limitation was that most participants were white, middle-aged to older health professionals, which may limit how broadly the findings apply to younger or more diverse populations.

"Future research is needed to evaluate the effects of resistance training on other health aspects and in younger populations," they wrote. 

Despite these limitations, the researchers highlighted the strengths of the study, including its large sample size, inclusion of both men and women, repeated exercise assessments and nearly three decades of follow-up. 

Why is consistency more important than intensity? 

According to Dr Sanjay Bhat, Sr Consultant - Interventional Cardiology, Aster CMI Hospital, Bengaluru, the findings are broadly consistent with current exercise recommendations, which advise adults to combine muscle-strengthening activities with regular aerobic exercise. He said the study suggests that moderate amounts of resistance training may be sufficient for most people to derive significant health benefits. 

"In practical terms, 90 to 120 minutes of strength training per week could mean two to four sessions lasting 30 to 45 minutes each. These sessions may include exercises such as squats, lunges, push-ups, resistance band exercises, weight machines or free weights," he said. 

Dr Bhat noted that the findings also reinforce the importance of combining strength training with aerobic activities such as brisk walking, cycling, swimming or jogging. According to him, people who engage in both forms of exercise appear to derive the greatest longevity benefits. 

"More strength training is not always better. Consistency is likely more important than excessive exercise volume," he said. 

Explaining why weights and cardio may complement each other, Dr Bhat said the two forms of exercise improve health through different mechanisms. While resistance training helps maintain muscle mass, bone strength, balance and blood sugar control, aerobic exercise strengthens the heart and lungs, improves circulation and helps lower blood pressure and cholesterol. 

"When combined, these benefits support overall physical function and may lower the risk of several chronic diseases. For most adults, a practical routine would include at least two strength-training sessions per week, totalling around 90–120 minutes, along with 150 minutes of moderate-intensity aerobic activity," he said, adding that the focus should be on maintaining a sustainable exercise routine rather than doing excessive amounts of either type. 

Commenting on the lower cardiovascular and neurological disease mortality observed in the study, Dr Bhat said several biological mechanisms could be involved. According to him, resistance training improves blood sugar regulation, reduces body fat, increases muscle mass and lowers inflammation, all of which support cardiovascular health. It may also help lower blood pressure, improve cholesterol levels and enhance overall metabolic function. 

"For brain health, resistance training may improve blood flow to the brain, support nerve function and promote the release of growth factors that help maintain healthy brain cells. These effects may contribute to a lower risk of neurological diseases as people age," he said. 

However, Dr Bhat cautioned that the study was observational and therefore cannot establish a cause-and-effect relationship. 

"While the findings provide valuable long-term evidence linking moderate resistance training with lower mortality risk, they should be interpreted as associations rather than proof of causation. Nevertheless, they strengthen existing evidence that regular strength training is an important part of healthy ageing and should be included alongside aerobic exercise in weekly routines," he added. 

This story is done in collaboration with First Check, which is the health journalism vertical of DataLEADS