would you eat your own brain to run a marathon?
you might already have! new research suggests this could be so!
Before I jump into this fascinating research an update from my running life!
I ran the Spring Equinox half marathon on March 23rd. I accidentally won the race because the woman who should have won blew up so I passed her with two miles to go, solidifying my tempo effort onto the podium. It felt like a tempo workout with more wind and hills than I would have picked, but definitely not something I’d be proud to call my half-marathon effort. I think I held back way too much in the interest of not blowing up, and actually enjoyed the race, meaning I did not run it in the way I should have. I’d consider it a humbling reminder that I need to practice racing and ride the potential of blowing up. It took me many half marathons, and many blow ups, to understand how to truly race something of that distance.
The good news is, I recovered pretty quickly and put in a solid 13x400 meter workout today. The body is feeling good. My ego has taken a hit and recovered. I am healthy and ready for the next one in a few weeks.
Anyway, back to the fun! Turns out when all we talk about is slamming carbs, we could be counting brain energy!
Reversible reduction in brain myelin content upon marathon running
The human brain is chuck full of neurons. Neurons carry information to and from the brain to control every single thing that happens in the body. Whether we can control them or not, the body is under a constant state of neuroendocrine control that maintains homeostasis. Neurons that need to travel long distances, like say from your spinal cord to your leg, have insulation around them that allow for faster movement of electrical impulses. This insulation is called myelin. Myelin is made by oligodendrocytes or Schwann cells, which are two types of supporting tissue called glial cells.
In mouse models, myelin is used to buffer energy. This means that when the brain is using a high amount of glucose, myelin is a protective mechanism against brain degradation. Using energy is a toxic process. Glycolysis, oxidative phosphorylation, lactate shuttling, creative-phosphate. These mechanisms that provide us with energy for metabolism, have other end products that can be harmful to tissues when they build up. Though debunked, this is probably where the concept of lactic acid comes from. The build up of lactate during exercise needs to be buffered or used for energy. As athletes approach their lactate threshold, the build up of lactate that is not converted is one of the many reasons we slow down.
The research presented here examined brains in runners surrounding a marathon race. Scans were taken pre and post run, then followed up a few times in the weeks and months after the effort. The results showed a decrease in myelin in the motor cortex, the sensory cortex and emotional processing centers immediately after the race. This makes sense because not only are we exercising our skeletal muscles during a long endurance event, we are also in a constant state of negotiations between our brain and body. When will we take fuel? Should we slow down going up this hill? Is it time for the final 5k surge? Representing about 40% of brain tissue, myelin is a fatty substance that can be used for energy in times of high demand. If you’ve ever felt a bit foggy after a hard effort or race, this could be why. The buffering system that helps to send electrical signals around the brain and body has been “eaten away”.
Is this a bad thing? Not necessarily! The researchers also found that myelin was back to normal levels two months post event, the neurons beginning to remyelinate already at 2 weeks. The degradation in brain tissue is completely reversible! Furthermore, there looks to be no permanent change in brain function and actually might help teach the brain to repair nerve tissue more efficiently! The information generated here could actually influence future research in understanding neurodegenerative diseases like multiple sclerosis, which occurs when myelin deteriorates causing neuronal abnormalities and eventual lack of motor control.
One item stuck out to me: “Matute suspects that the temporary reduction in myelin would be greater in people who are less fit, and that the opposite would be true in ultra-runners, people who run races longer than the 42 kilometres that make up a marathon.”
So maybe all this running is making us smarter and more emotionally aware…but also maybe don’t take the MCAT right after your marathon.
I see that Matute has run 18 marathons, but I’m skeptical or at least nervous of his assertion that Ultra runners are in better shape. In general, I would guess that ultra runners and marathon runners might have comparable levels of fitness at a minimum. I would also postulate that the potential for cognitive impact is greater for ultra runners as the slow burn of an ultra event combined with sleep, deprivation, complex, fueling, and hydration requirements make ultra’s strain on the brain greater than that of a marathon. Although I have ended up in the medical tent several times at the end of hard marathon efforts, once I was properly fueled, I generally felt more or less normal afterwords. Whereas ultra events have left me at times in a brain fog for at least a few weeks. But hopefully the body is able to adapt to this brain, stress and recover faster after time.