Exercise Boosts Your Brainpower - Part 2

old dog new trick

Part 2 - Cardio Exercise Helps You Make New Brain Cells And Keep Old Ones.

I just finished telling you that thousands of your brain cells die every day because they don't the get resources they need to stay alive. What I haven't told you is that your brain can potentially make thousands of new neurons every day to replace the ones that die. I'll bet you didn't know that your brain makes thousands of new brain cells every day throughout your entire life. It's true! New research has shown that even eldery adults produce new neurons every day1! So the saying "You can't teach an old dog new tricks" can finally be laid to rest as nothing but gibberish. The only catch is that not all of these new neurons survive. In fact, the majority of them die within the first week. But, there is something you can do to increase the number of new neurons being produced and keep them alive. You guessed it - exercise. Let me tell you a story about two groups of mice:

A Story:

One group of mice were placed in a cage with nothing in it but food and water. Another group was placed in a cage with food, water, and a running wheel. They discovered that mice in the cage with the running wheel would run an average of 3 miles per day. After a few weeks both groups of mice had the number of new neurons counted. And guess what - the mice with the running wheel had 200% more new neurons than the sedentary group2!

This experiment can't be performed on humans because it involves killing the animal to count the new brain cells, but what holds true for one mammal almost always holds true for others. As an example, consider this: Just a decade ago no one thought that the human brain makes new neurons in old age, but then it was discovered that rats do3, and then it was discovered that guinea pigs do4, and then in monkeys5, and finally, just a few years ago, in humans1. This means that cardiovascular exercise dramatically increases the number of new brain cells created in your very own brain! This process, called neurogenesis, has more of an impact on your cognition the older you get since the number of new neurons continues to add up. Over a lifetime, an exerciser could have 10%-20% more brain cells than someone who didn't exercise! The scientist who did the mice study went out and bought a pair of running shoes when the results came in. I would too!

Furthermore, the mice study showed that the exercise group of mice had a better memory and better spatial recognition and perception. Just because of running! The mice were bred to be genetically the same.

This all makes sense though, because the stronger your cardiovascular system is, the easier it for your brain cells to get oxygen and nutrients, which makes your cells work better and stay alive. And not only do they survive, they migrate to other areas of your brain and continue to grow and incorporate into your existing network of neurons6, making your brain better. Do you think this might have something to do with how new memories are formed? I certainly think so.

So here's the take-home message:

Your brain makes new neurons every day. Exercise flips on genes that tell your brain to make more new neurons and keep them alive. More new brain cells means you learn faster and remember more.

I hope you're convinced by now that you need exercise to maximize your brain's potential, but if you're not, in the next article in this series I will discuss actual human studies that look at the direct impact of cardio exercise on human cognition.

References:

  1. Eriksson PS et al. Neurogenesis in the adult human hippocampus. Nature Med. 4:1313-1317. 1998.
  2. van Praag H, Kempermann G, Gage FH. Running increases cell proliferation and neurogenesis in the adult mouse dentate gyrus. Nature Neurosci. 2:266-270. 1999.
  3. Altman J, Das GD. Autoradiographic and histological evidence of postnatal hippocampal neurogenesis in rats. J. Comp. Neurol. 124:310-335. 1965.
  4. Altman J, Das GD. Postnatal neurogenesis in the guinea-pig. Nature. 214:1098-1101. 1967.
  5. Gould E et al. Proliferation of granule cell precursors in the dentate gyrus of adult monkeys is diminished by stress. PNAS. 95:3168-3171. 1998.
  6. Tashiro A et al. NMDA-receptor-mediated, cell-specific integration of new neurons in adult dentate gyrus. Nature. 442:929-933. 2006.

Other articles in this series: