Exercise can regrow brain cells and help avert dementia

EXERCISE could protect against Alzheimer’s by triggering a hormone that helps regrow brain cells, a study has found.

Scientists have known for some time that exercise reduces the risk of developing dementia, but did not know if there was a direct link.

Now a series of studies has shown that a hormone released during exercise, called irisin, is depleted in the brains of people with Alzheimer’s, and can protect animals against memory loss and brain damage.

Mice who swam nearly every day for five weeks did not develop memory impairment despite getting infusions of beta amyloid – the brain-cell clogging protein implicated in Alzheimer’s.

The studies suggest not only that exercise really does protect against dementia, but also that a drug mimicking irisin could be the answer to preventing the disease.

“I would certainly encourage everyone to exercise, to promote brain function and overall health,” said Dr Ottavio Arancio, a professor of pathology and cell biology at Columbia University.

“But that’s not possible for many people, especially those with age-related conditions like heart disease. For those individuals, there’s a particular need for drugs that can mimic the effects of irisin and protect synapses and prevent cognitive decline.”

There are currently 850,000 people living with dementia in Britain and that figure is expected to rise as the population ages.

But despite decades of research, no drug has yet been found to reverse or prevent the condition, and several major drugs companies have now pulled out of testing altogether.

The research was published in Nature Medicine.