Under extreme conditions like running a marathon, your body might look to unlikely sources for fuel
Pushing your body to its limits isn’t always pretty. From severe muscle damage, to stress fractures, to joint wear-and-tear, marathon running can leave your body battered and bruised.
As the London Marathon fast approaches, new research suggests running more than 26 miles could have an alarming effect on your brain.
According to a new study, your brain starts ‘eating itself’ during strenuous endurance exercise to make up for lost fuel.
By scanning the brains of marathon runners just after a race, scientists have found that brain cells can start munching on myelin, a fatty sheath that protects nerves in the brain. The researchers say their findings suggest that the brain consumes myelin as an energy source under extreme exercise conditions.
Myelin, which helps messages travel quickly and efficiently in the brain, is essential for things like muscle movement and coordination. Damaged myelin can cause problems with nerve signals, leading to conditions such as multiple sclerosis.
The new findings suggest that some brain cells may even recycle myelin for fuel, but in extreme conditions, when other fuel sources are depleted.
The researchers scanned the brains of 10 marathon runners before and after a race. In the 24 to 48 hours after a marathon, they found big changes in the amount of myelin in their brains, specifically in regions related to motor function and emotional integration. In some cases, brain areas were depleted by up to 28 per cent.
However, the effects seem to be temporary. The study found that it took two weeks for the myelin to start coming back and two weeks for their myelin levels to stabilise.
The team, led by Pedro Ramos-Cabrer and Alberto Cabrera-Zubizarreta, says their findings “may open up a new view of myelin as an energy store ready to use when common brain nutrients are in short supply.”
“The areas that we saw have more significant changes were those related to motor circuits and the centre of emotional control of the brain,” Cabrer told Live Science, suggesting that this reflects the mental and physical effort the brain must maintain to get through a marathon.
The findings hint at a whole new level of neuroplasticity, which may help keep the human brain functioning during prolonged stints of intense endurance.
The study was published in the journal Nature Metabolism.