A new study has revealed that regular weight training not only strengthens the body but also protects the aging brain from deterioration.
In older adults already experiencing mild cognitive impairment, twice-weekly resistance workouts helped preserve brain structure and improved memory - offering a promising, low-cost approach to slowing or possibly preventing the onset of dementia.
A strong ally against dementia
The research was carried out at the State University of Campinas (UNICAMP) in São Paulo, Brazil. The study involved 44 individuals with mild cognitive impairment, a condition that bridges the gap between normal aging and early Alzheimer’s disease .
Isadora Ribeiro is a doctoral fellow at UNICAMP’s School of Medical Sciences and first author of the study.
“We already knew that there would be physical improvement. Cognitive improvement was also imagined, but we wanted to see the effect of weight training on the brains of older people with mild cognitive impairment,” said Ribeiro.
“The study showed that, fortunately, weight training is a strong ally against dementia, even for people who are already at high risk of developing it.”
Resistance training and brain structure
Participants who completed six months of weight training, with two sessions each week, showed significant neurological benefits.
MRI scans conducted before and after the study revealed that areas of the brain associated with memory and Alzheimer’s disease - the hippocampus and precuneus - were protected from the shrinkage typically seen in individuals with cognitive decline.
Additionally, there were improvements in the integrity of white matter, which reflects the health of neurons and their communication pathways.
Weight training and mild dementia
These findings mark the first time that the structural impact of weight training on the brains of people with mild cognitive impairment has been demonstrated.
“As well as neuropsychological tests, we also performed MRI scans at the beginning and end of the study,” said Marcio Balthazar, the study’s supervisor and a researcher at the Brazilian Institute for Neuroscience and Neurotechnology (BRAINN).
“These results are very important because they indicate the need to include more physical educators in the public health system at the primary health care level since increased muscle strength is associated with a reduced risk of dementia . It’s a less complex and cheaper treatment that can protect people from serious diseases.”
Weight training for dementia intervention
The researchers pointed out that exercise could offer a cost-effective alternative to expensive drug treatments.
“For example, the new anti-amyloid drugs approved in the United States indicated for the treatment of dementia and for people with mild cognitive impairment, cost around USD 30,000 a year. That’s a very high cost,” noted Balthazar.
“These non-pharmacological measures, as we’ve shown is the case with weight training, are effective, not only in preventing dementia but also in improving mild cognitive impairment.”
To evaluate the effects of strength training, participants were split into two groups. One group engaged in supervised resistance training with progressive loads at moderate to high intensity, while the other group - the control - remained sedentary.
At the end of the trial, only the active group demonstrated improvement in verbal episodic memory, greater neural integrity, and brain regions shielded from atrophy. The control group, in contrast, exhibited continued cognitive and structural decline.
Hope for reversing cognitive decline
According to Ribeiro, the results suggest that the benefits of resistance training might grow over time.
“A characteristic of people with mild cognitive impairment is that they have volume loss in some brain regions associated with the development of Alzheimer’s. But in the group that did strength training, the right side of the hippocampus and precuneus were protected from atrophy,” said Ribeiro.
“This result justifies the importance of regular weight training, especially for older people.”
Longer weight training may delay dementia
Ribeiro also noted that a longer training period might lead to even more promising results.
“All the individuals in the bodybuilding group showed improvements in memory and brain anatomy. However, five of them reached the end of the study without a clinical diagnosis of mild cognitive impairment, such was their improvement.”
“This leads us to imagine that longer training sessions, lasting three years, for example, could reverse this diagnosis or delay any kind of dementia progression. It’s certainly something to be hopeful about and something that needs to be studied in the future.”
How weight training protects the brain
The team believes that resistance exercise protects the brain through both biological and systemic mechanisms.
On one hand, it increases levels of neural growth factors essential for neuron survival and communication. On the other, it combats inflammation - an underlying factor in neurodegenerative diseases.
“Any physical exercise, whether weight training or aerobic activity, is known to increase levels of a chemical involved in brain cell growth. It can also mobilize anti-inflammatory T-cells. This is key,” explained Balthazar.
“After all, the more pro-inflammatory protein that is released in the body, the greater the chance of developing dementia, accelerating the neurodegenerative process and forming dysfunctional proteins that eventually kill neurons.”
Uncovering the biological links
To explore this further, the researchers measured participants' levels of irisin and brain-derived neurotrophic factor (BDNF) - proteins stimulated by muscle activity and associated with brain plasticity and resilience. The data from these measurements are currently under review.
“It’s a continuation of this study in which we’ll try to better understand how these factors are related to changes in brain anatomy. We believe that it’s a set of anti-inflammatory and neuroprotective factors that lead to these changes,” Ribeiro said.
As researchers continue to uncover the biological links between physical strength and cognitive health, this study adds to the growing body of evidence that lifestyle interventions - like weight training - can be powerful tools in the fight against dementia.