A groundbreaking new study has uncovered a powerful connection between what your body is made of and how old your brain appears to be. The research suggests that higher muscle mass is associated with a younger-looking brain, while increased levels of deep belly fat are linked to an older-appearing brain.
The Study: Scans Reveal a Clear Pattern
Researchers from Washington University School of Medicine in St. Louis, Missouri, along with other institutions, conducted the analysis. They examined whole-body MRI scans from over 1,000 healthy individuals aged between 40 and their early 60s.
Using artificial intelligence, the team calculated each participant's total muscle mass and body fat levels. To determine the apparent age of each person's brain, they compared the brain scans against a vast database containing tens of thousands of other scans. This allowed them to see if a participant's brain matched their chronological age or appeared younger or older.
The results were striking. "The larger the muscle bulk, the younger-looking the brain," explained the study's senior author, Dr Cyrus Raji, an associate professor of radiology and neurology. "And the more visceral fat that was present, the older-looking the brain."
The Wider Context of Cognitive Health
This research, presented in December 2025 at the annual meeting of the Radiological Society of North America and highlighted in The Washington Post, adds a significant piece to the puzzle of brain health and ageing. It is important to note that the study is awaiting formal publication and peer review.
The findings align with established knowledge about the benefits of physical activity for the mind. The Alzheimer's Association states that exercise may help lower the risk of developing Alzheimer's disease or other forms of dementia. Currently, more than seven million Americans aged 65 and older are living with Alzheimer's, a figure projected to soar to nearly 13 million by 2050.
A Multi-Pronged Approach to Brain Protection
While building muscle through activities like weight training appears beneficial, experts emphasise that it is just one part of a holistic strategy for maintaining cognitive function as we age.
Supporting evidence comes from a separate two-year clinical trial known as the U.S. POINTER study, published in July. That research found that simultaneously targeting multiple risk factors yielded the best results. A combined regimen of physical and cognitive exercise, improved nutrition, and careful health monitoring was shown to enhance brain function in older adults.
The successful exercise plan in that trial included 30 to 35 minutes of moderate-to-intense aerobic activity four times per week, complemented by strength and flexibility workouts twice a week.
Together, these studies reinforce a powerful message: the choices we make about our physical health, from the food we eat to the weights we lift, have a profound and measurable impact on the long-term vitality of our brains.
