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Could exercise reverse dementia? Study finds activity hormone may protect brain

Cognitive decline in patients with Alzheimer’s could be helped by a hormone that is naturally released during exercise, according to a study in Brazil and the US.

Scientists researched the effects of irisin, a protein emitted by the body during physical activity, and found that it could help stave off dementia.

Power of exercise? Scientists in Brazil and the US studied the impact of exercise hormone irisin on genetically engineered mice and found that mental faculties were impaired when the levels of the protein were lowered

During research on genetically engineered mice, irisin levels were lowered to study how brain function was affected. When impairment was recorded, scientists were able to remedy it by bolstering irisin levels.

Patients diagnosed with Alzheimer’s were found to have lower levels of irisin in their brains compared to those who didn’t have dementia.

Led by Dr Fernana de Felice, from the Federal University of Rio de Janeiro in Brazil, researchers concluded that irisin, in either natural or drug form, could offer a ‘novel strategy’ for helping preserve mental faculties in people with Alzheimer’s.

British scientists have said further research is needed on humans but said the study was promising.

Dr Rosa Sancho, from Alzheimer’s Research UK, said: “We know that physical activity is linked to better brain health as we age, and this research highlights a biological mechanism that may contribute to this beneficial effect.


Head of research at the Alzheimer’s Society charity, Dr James Pickett, said more research was needed but the study showed ‘mounting evidence of the relationship between lifestyle factors, like physical fitness, and dementia’.

“Drugs designed to target the hormone identified in this research could potentially bring some of the benefits of physical activity to people who may be less able to exercise.”

Dr James Pickett, head of research at the Alzheimer’s Society charity, added: “Although this study was only in mice, it adds to mounting evidence of the relationship between lifestyle factors, like physical fitness, and dementia.

“This is a promising avenue for more research and potential new therapies in future.”