Exercise is interesting in terms of effects on the brain because it works in about 4 or 5 different ways.
One of the most obvious ways is blood flow. So if you get your heart working your brain is going to be filled with
oxygen rich blood and nutrients, so that’s the main way that we thought it helps.
The other way that’s sort of interesting, is it’s been thought that exercise produces new neurons.
So exercise induces the production of growth factors, one’s called BDNF and it actually
stimulates the production of new brain cells.
Now, when I was in school 20 years ago we were told you can’t get any new brain cells, so when you’re born, that’s it, you’re not going to make any more. But more recently we’ve found that exercise is a really good
way of stimulating brain cell production. And some of these are functional. And so just
this notion that something that you can do can generate new brain cells is a really great
thing to think about.
We were wondering why exercise helps the brain, and what one theory is, is that it just reduces stress.
So maybe it’s not that blood is coming to the brain.
Maybe you’re less stressed. And that was something that imaging allowed us to test.
And so we scanned a whole lot of people with high cortisol levels, and so
if you’re stressed, if you’re angry about something, or even if you’re stuck in traffic,
your cortisol levels can be very high.
One of the things we found is that the people with high cortisol levels has lost brain tissue faster.
Well, that’s a serious problem so as soon as you know that’s true, you can look at ways of reducing
your cortisol and so that’s a very easy thing to do.
We can get less stressed by exercising, walking, taking breaks.
And so imaging established a physical connection, between something in your blood, cortisol
that’s a sign of stress, and actual physical changes in the brain and that’s very useful to know.
Take care of your brain. There’s a lot of ways we know that you can take care of your brain.
You can eat a good diet, you can exercise, you can reduce stress, you can make sure you’re well educated,
and these things just build up a sort of mental bank account for the future
and so even though it seems like work is hard, you’re building a store of brain connections
that you’ll need the for the rest of your
life. So these are practical messages that we’ve learned from imaging a lot of people.