A simple question has challenged scientists, doctors, and fitness experts for decades: if your goal is to live longer and stay healthier, should you focus on cardio or strength training?
A major new study suggests the answer may not be one or the other.
Researchers analyzing nearly 30 years of health data from more than 147,000 adults have found that the greatest survival benefits appear to come from combining aerobic exercise with a specific amount of weekly strength training.
The findings, published in the British Journal of Sports Medicine, add to growing evidence that a balanced exercise routine may be one of the most powerful tools available for protecting long-term health and extending lifespan.
A three-decade look at exercise and longevity
The research team examined data collected from three of the world's most respected long-term health studies: the Health Professionals Follow-up Study, the Nurses' Health Study, and the Nurses' Health Study II.
Together, the studies followed more than 147,000 participants with an average age of 54 years.
Every two years, participants reported details about their physical activity, including both aerobic exercise and resistance training habits. Researchers then compared these exercise patterns with mortality outcomes over the following decades.
The goal was not simply to determine whether exercise is beneficial—a fact already well established—but to identify the most effective combination of exercise types for reducing the risk of premature death.
The strength-training sweet spot
One of the study's most striking findings involved resistance training.
Researchers found that adults who performed approximately 90 to 120 minutes of strength training per week experienced a 13% lower risk of death from any cause compared with those who did not engage in resistance exercise.
The benefits extended beyond overall mortality.
Participants in this range also showed:
A 19% lower risk of cardiovascular disease-related death
A 27% lower risk of death from neurological diseases
Importantly, researchers observed that the benefits appeared to plateau after roughly two hours per week, suggesting that more strength training did not necessarily translate into greater survival advantages.
Why strength training matters
According to Dr. Edward Giovannucci, Professor of Nutrition and Epidemiology at the Harvard T.H. Chan School of Public Health and corresponding author of the study, the role of resistance training in longevity has remained less understood than aerobic exercise.
"The benefits of aerobic activity for longevity are already well established," Giovannucci explained.
"What has been less clear is how resistance training relates to long-term mortality risk, especially at different volumes and in combination with aerobic activity."
The findings suggest that muscle-strengthening activities may contribute to healthy aging through biological mechanisms that differ from traditional cardiovascular exercise.
Strength training has been associated with improved glucose regulation, better body composition, increased muscle preservation, stronger bones, and reduced frailty—all factors linked to longer-term health outcomes.
The most powerful combination
While strength training alone was beneficial, researchers discovered that the lowest mortality risks were observed among people who combined resistance training with high levels of aerobic activity.
Specifically, individuals who accumulated substantial aerobic exercise while performing approximately 60 to 119 minutes of weekly strength training experienced the greatest reduction in overall mortality risk.
According to Dr. Yiwen Zhang, first author of the study and postdoctoral research fellow at Harvard T.H. Chan School of Public Health, different forms of exercise influence health through different physiological pathways.
"Aerobic activity and resistance training may benefit health through different pathways, so it is important to study them separately and together," Zhang said.
Aerobic exercise improves cardiovascular fitness, blood circulation, blood pressure regulation, and metabolic health. Strength training, meanwhile, helps preserve muscle mass, maintain functional independence, and improve glucose metabolism.
When combined, the two approaches may create a broader protective effect across multiple organ systems.
An unexpected neurological benefit
Among the study's most intriguing findings was the association between strength training and lower mortality from neurological diseases.
Participants who engaged in regular resistance training appeared less likely to die from neurological conditions compared with those who performed little or no strength exercise.
However, researchers caution that this finding requires further investigation.
Giovannucci noted that neurological diseases such as Alzheimer's disease often begin developing years before diagnosis. Early symptoms may reduce an individual's ability or motivation to exercise, potentially influencing the observed relationship.
Despite these limitations, the results add to a growing body of research suggesting that physical activity may play an important role in preserving cognitive health during aging.
Experts say exercise should not be an either-or choice
Independent experts say the findings reinforce an important message for the public.
Dr. Swapnil Patel, Vice Chair of the Department of Medicine at Hackensack Meridian Jersey Shore University Medical Center, said many people tend to focus exclusively on either cardio or strength training.
"This study provides compelling long-term evidence that resistance training offers independent benefits and appears to further reduce mortality risk when combined with aerobic exercise," Patel said.
He explained that aerobic activity and strength training affect the body in fundamentally different ways, making both important components of a healthy lifestyle.
The study is particularly significant, he added, because it highlights the potential role of resistance training in neurological health—an area receiving increasing attention as populations age and dementia rates rise globally.
Building a complete exercise routine
Experts emphasize that strength training should not replace other forms of physical activity.
Dr. David Cutler, a board-certified family medicine physician at Providence Saint John's Health Center in California, said the findings underscore the importance of a comprehensive exercise programme.
"A lot of people focus on one form of exercise," Cutler said.
He noted that the most effective long-term strategy often includes a combination of aerobic exercise, resistance training, stretching, and core-strengthening activities.
For people new to strength training, he recommends seeking guidance from qualified fitness professionals to reduce the risk of injury and ensure proper technique.
What this means for healthy aging
As life expectancy increases around the world, researchers are paying closer attention not only to how long people live but also to how well they age.
The new findings suggest that achieving longevity may not require extreme exercise routines or hours in the gym every day.
Instead, a balanced weekly programme that combines regular aerobic activity with approximately one to two hours of strength training may offer some of the strongest protection against premature death, cardiovascular disease, and potentially even neurological decline.
For millions seeking a practical roadmap to healthier aging, the message from this research is remarkably clear: cardio and strength training work best together.
Stay informed, stay alert
CLICK HERE TO JOIN Medical News Pakistan on WhatsApp for real-time health alerts, expert insights, and breakthrough medical discoveries.