It’s easy to understand the links between exercise and bodily health. You can see muscles grow, or – if you’re a scientist – slice out a tiny sample of muscle and measure the molecular changes triggered by your workout.
In contrast, it’s not intuitively obvious why or how lifting weights or going for a bike ride should boost brain health. But as evidence of the strong links between physical activity and brain function keeps piling up, scientists are finding new ways of peering into the brain to unravel the mechanisms – and they’re discovering that exercise has more ways of improving your neural wiring than previously suspected.
The latest finding, published this week in the journal Cell Reports by researchers at the Ottawa Hospital and the University of Ottawa, is that exercise helps kick-start a repair process that strengthens existing brain connections, in part by fixing the myelin “insulation” that protects nerve fibres in the brain. That’s particularly intriguing because myelin damage is a hallmark of certain brain diseases such as multiple sclerosis.
The study, led by senior author David Picketts and his former doctoral student Matías Alvarez-Saavedra, involved mice that were genetically modified to have a brain condition called cerebellar ataxia that disrupted their balance and movement. These mice typically lived for only 25 to 40 days – unless they were given access to an exercise wheel.
“We found that exercise could help these animals survive,” explains Picketts. The running mice lived for more than a year, and showed other signs of brain recovery such as improved balance. Examining the brains of the exercising mice showed that neurons in the damaged region had more myelin insulation.
The key difference? A protein called VGF, one of many molecules produced throughout the brain and body during exercise (the name stands for … nothing – it’s “non-acronymic”). When the researchers used a non-replicating virus to inject VGF into the bloodstream of non-exercising mice, these mice also lived longer and had signs of myelin repair in their brains.