Saturday, 4 August 2012

Olympics special: Exercise makes you smarter

It's the Olympics! Woohoo! I love the Olympics, so I'm going to celebrate with a series of sports-and-brain related posts.

Taken by me at the Vancouver 2010 Opening Ceremony. Awesome, eh?
          You are born with hundreds of billions of neurons in your brain. They wire together in vast networks that control all your thoughts and feelings, and everything that you do. And then they start to die.
          I've got some bad news for you. Throughout most of your life, your brain cells are dying. The good news is, that isn't always a bad thing. You're born with more neurons than you need. When you're very young, those extra neurons die, but that's okay. If they all wired into the network, it would be like being stuck in an overcrowded room with 50 different people trying and have deep conversations with you while the lights flash and the floors rumble and the music blasts forever. In other words, it would be too much for your brain to handle. You'd have a seizure. Really. That's not an analogy. If those extra neurons didn't die, you would seize. So it's a good thing that some neurons die during infancy and early childhood.
          But not all neuron death is good, especially when you're older. There's a group of diseases called the neurodegenerative diseases, where too many neurons die, leading to difficulties in memory, muscle movement, learning, and, in many cases, death. Even in healthy people, neurons are always dying. About 5-6% of them die every year. This is a large part of the reason why even healthy elderly people are less able to remember things. Even people in their late 20s, like myself, don't learn or remember as well as they did when they were kids.
          The good news is, you can slow this down. The better news is, even though your neurons are always dying, they're also always being born. You have a potentially endless supply of new neurons just waiting to be born. This is huge news. It's the great big thing in neuroscience right now. When I was in school, I was told that new neurons were never born. A person was born with all the neurons they would ever have, and once those neurons started to die, too bad! There was nothing to be done. But thanks to the work of neuroscientists over the last decade, we now know that this is a myth! New neurons can be born. Thank you, neural stem cells!

This picture shows new neurons being born in an area of the brain called the hippocampus, which is important for learning and memory. The red neurons are the newborn ones. I got this picture from Wikipedia, but it's originally from Faiz, et al., BMC Neurosci, 2005

           And not only are new neurons being born all the time, but you can increase the rate at which they're born. You can make new neurons! You can slow neuron death! You can't reverse the process completely, but you can start to apply the brakes.
          One way is to keep your brain active. Do puzzles, learn new things, debate issues, read books, and for the love of all that is good and brainy, get away from that TV.
          The other way is to keep your body active. That's right! Exercise your way to a smarter brain!
          One of the hot topics in neuroscience right now is that exercise increases neurogenesis. "Neurogenesis" means "neuron birth". When you exercise, new neurons are born. This translates to better memory and faster learning. You don't have to do much. No one's asking you to be an Olympian. But take the stairs instead of the elevator. Bike a mile instead of driving. Grab a ball and some friends and get your sport on. The type of exercise doesn't matter, just that you do it.
           Keeping both your brain and body active is a great way to slow neuron death, increase neuron birth, and increase the number of connections that neurons make with each other. That means faster learning and longer-lasting memories. To me, that sounds like an excellent reason to work up a sweat.

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