A British study, repeated in other countries, took 10,000 civil servants aged 35 to 55. They rated their exercise habits high, medium or low, and then measured their cognitive function. You can hear it coming can’t you? Those who did the most exercise had the highest cognitive function, especially when it came to problem-solving which uses more of the brain.
OK! Let’s look at what’s going on. Why is exercise good for the brain?
It’s all to do, believe it or not, with digestion. That’s the process of turning the food you ingest into sugar – glucose, which provides energy for your body. The glucose is absorbed into the blood from the intestines and then, through the blood, reaches every part of the body. It goes into each cell of your body, which utilises it for energy, creating waste as a byproduct in the process. Not everybody realises that this waste is actually toxic to the body and quite deadly. It can even cause DNA mutations, and we all know that can be a tad inconvenient, to say the least!
So what happens is that the oxygen we breathe behaves like a sponge and mops up this toxic waste, transforming it into carbon dioxide, which is also poisonous, but transferable, and is then carried via the blood to the lungs, and breathed out into the atmosphere.
Your brain weighs about 2% of your total body weight but uses up about 20% of the total energy used by the body. This is about 10 times more than you might expect. It’s so fuel-hungry that it can only fire up about 2% of its neurons at any one time. In fact if it tried to work harder than that the glucose supply would be exhausted and you’d faint. That’s like nature’s way of telling you to slow down!
So now it’s beginning to make a bit of sense. Your brain is using a hell of a lot of energy, and is therefore making a lot of toxic waste in the process. And remember it’s oxygen that transforms that waste and gets it out of the body. Exercise makes you breathe faster and deeper and gets oxygen into your system.
And just to demonstrate how essential oxygen is to the good functioning of your brain, you’ve only got to look at what happens when you starve it. You can go without food for 30 days. You can go for about a week without water. But 5 min without oxygen gives you permanent and serious brain damage. Oxygen is absolutely essential to the brain. But how does it improve your memory?
Let’s have a look at what’s actually happening when you exercise. Exercise stimulates the release of nitric oxide by your blood vessels which dilates them and regulates the flow of blood. As a consequence, new blood vessels are created and work their way deeper into your tissues so that there is more access by those tissues to the oxygen and glucose they need, and the resultant toxic waste is removed quicker. Aerobic exercise causes the heart to pump faster which increases the blood flow.
But, not only that, exercise stimulates one of the NGFs (Nerve Growth Factors) in the brain: BDNH. In other words, Brain Derived Neurotrophic Hormone is created when you exercise. What’s more, the more exercise you do, the more BDNH is produced.
So what, I hear you ask! BDNH behaves a little like a fertiliser does on your flower bed. It encourages existing brain cells to stay young and healthy and also stimulates neurogenesis -in other words, the creation of new cells and healthy tissue. Brain imaging shows increased levels of blood in the brain, particularly in the dentate gyrus in the hippocampus, which is essential for the formation of memories.
So there you have it! Exercise makes you breathe faster and deeper. That gets more oxygen into your brain and stimulates the formation of new brain cells.
Quite simply – exercise will improve your memory.