Lifting weights can slow down biological brain aging in older adults

Lifting weights might help keep your mind young. A new study published in GeroScience suggests that older adults who engage in regular resistance training can actively slow down the biological aging process in their brains. These findings provide evidence that strength-building exercises offer widespread benefits for long-term cognitive health.

Scientists have consistently linked physical exercise to better memory, sharper thinking, and a lower risk of brain diseases. Past studies tend to focus on how aerobic workouts, like running or swimming, change specific isolated parts of the brain. For instance, many projects look at changes in the physical size of the hippocampus, a brain region tied to memory.

As a result, the effects of resistance training on the entire brain remained mostly a mystery. Scientists wanted to see if lifting weights could improve overall brain health rather than just tweaking a single area. To do this, they used advanced computer models called brain clocks.

A brain clock is a mathematical tool that analyzes medical images of a person’s brain to guess their age based on biological wear and tear. If the tool guesses an age lower than the person’s actual chronological age, it suggests the brain is aging slowly and healthily. The researchers set out to quantify exactly how a year of strength training influences this biological brain age.

“For years, we’ve known that exercise is good for the brain, but most studies looked at isolated pieces (like the hippocampus or specific networks) without telling us whether exercise actually slows brain aging as a whole. At the same time, results across studies have been inconsistent, and resistance training has been particularly understudied,” explained study author Agustín Ibáñez, a professor at the Global Brain Health Institute and director of the Latin American Brain Health Institute (BrainLat) at the Universidad Adolfo Ibáñez.

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“What we wanted to address was a very practical and urgent question: can a real-world intervention like strength training actually change the trajectory of brain aging? To do that, we used brain clocks, computational models that capture global brain health, in a randomized trial. That allowed us to move beyond fragmented evidence and test whether exercise impacts the brain at a systems level.”

To measure these changes, the scientists first trained their brain clock model using brain scan data from 2,433 healthy adults. These scans were taken using functional magnetic resonance imaging. This technology measures brain activity by detecting changes in blood flow while a person is simply resting.

This large dataset helped the computer program learn what a typical brain network looks like at any given age. Next, the researchers applied this trained brain clock to a study sample of 309 healthy older adults. These participants were between 62 and 70 years old and were approaching retirement age.

The scientists randomly divided the volunteers into three different groups to compare different exercise habits. The first group engaged in heavy resistance training. They attended three supervised weightlifting sessions at a training center every week for a full year.

The second group completed moderate-intensity training. This routine included one supervised session and two unsupervised home workouts each week. The exercise intensity for both groups progressed gradually over the one-year period to safely build endurance and balance.

The third group acted as a non-exercise control group. These participants were instructed to stick to their normal daily routines and avoid strenuous physical activity. All 309 participants underwent comprehensive brain scans and physical fitness tests at the beginning of the study.

The researchers tested the participants’ physical fitness by measuring their leg strength using standardized equipment. They repeated all the brain scans and strength tests after one year of training. The scientists also brought the participants back for a final round of testing after two years to see if any changes lasted.

The scientists found that resistance training led to noticeable improvements in brain connectivity. In the heavy resistance training group, the brain scans showed increased communication between prefrontal brain regions compared to the control group. The prefrontal cortex is an area located at the front of the brain that handles complex tasks like planning and paying attention.

The brain clock analysis provided evidence for even broader benefits across the whole brain. After the one-year fitness program, both the heavy and moderate exercise groups showed a significant reduction in their biological brain age. On average, the physical training reduced the participants’ brain age by 1.4 to 2.3 years. These younger brain ages were maintained when the researchers tested the participants again at the two-year mark.

“A 1-year, or even a few months, reduction in brain age might sound modest, but in aging research, that’s actually meaningful,” Ibáñez told PsyPost. “Brain aging is a slow, cumulative process, and differences of this magnitude have been linked to better cognitive function, lower risk of decline, and a healthier future lifespan. Think of it less as a ‘quick fix’ and more as shifting your long-term trajectory—small changes sustained over time can have large downstream effects.”

The non-exercise control group did not experience any significant changes in their brain age during this same period.

The scientists tested specific networks, like the systems controlling movement or vision, to see if the changes were isolated. They found that the anti-aging effects did not come from just one network. This suggests that resistance training causes a widespread reorganization of brain activity that benefits global brain health.

“The effects were global rather than localized,” Ibáñez explained. “We expected changes in specific networks, but instead we saw a distributed, whole-brain pattern. That suggests exercise works through systemic mechanisms (like vascular, metabolic, and inflammatory processes) rather than targeting a single brain region.”

The researchers also looked at how physical performance changes related to these younger brain ages. They found a modest link between improved leg strength and a reduced brain age, specifically in the moderate-intensity group. This indicates that gaining physical strength tends to track alongside improvements in global brain health.

This association did not appear in the heavy training group, which the scientists suspect might be due to a ceiling effect. Essentially, more intense training does not always yield a proportionally larger reduction in brain age. Even moderate amounts of physical work can provide substantial biological benefits.

“The key message is simple but powerful: regular strength training can slow your brain’s aging,” Ibáñez said. “We found that people who engaged in resistance exercise (moderate or intense) showed brains that looked about 1–2 years younger over time compared to those who didn’t exercise. This is not about elite fitness. Even moderate, consistent exercise can have measurable benefits for how your brain ages.”

While the findings are promising, the scientists noted a few limitations to keep in mind. The study focused entirely on healthy older adults living in a high-income European country. This specific demographic means the results might not apply to people with existing medical conditions or those from different socioeconomic backgrounds.

“A key caveat is that this does not mean exercise ‘reverses aging’ or replaces medical care,” Ibáñez noted. “Also, brain age is a probabilistic biomarker (it reflects patterns of brain health), not a literal clock. So we should interpret these results as evidence of improved brain resilience, not as a precise measure of turning back time.”

Future research will help clarify if these numbers translate into noticeable protections against memory loss decades later. Future studies could also test these exercise programs in more diverse groups of people. Additional projects might also explore the exact biological mechanisms that link muscle strength to brain health.

“We want to move toward precision prevention,” Ibáñez said. “That means understanding who benefits most from which type of intervention, integrating exercise with other factors like social environment, cardiovascular health, creativity, nutritions, and the mitigating exposome (environmental factors that impact health). We’re also working on combining brain clocks with biological and behavioral data to better predict individual aging trajectories. We dream of scalable, personalized strategies for brain health across populations.”

The study, “Randomized controlled trial of resistance exercise and brain aging clocks,” was authored by Raul Gonzalez-Gomez, Naiara Demnitz, Carlos Coronel, Anne Theil Gates, Michael Kjaer, Hartwig R. Siebner, Carl-Johan Boraxbekk, and Agustin M. Ibanez.