As a neuroscientist, I've always been fascinated with the awesome malleability of our brains. I focused much of my early career studying the changes in the brain that occur as we form new long-term memories. But more recently, I've become fascinated with a very different form of brain plasticity.
This new research direction was inspired by striking changes I noticed in my own brain after an exercise “wake-up call” finally motivated me to start a regular exercise routine. Yes, I got stronger and fit, but the most profound impact of this new exercise routine was not on my body but on my brain. I was in a great mood, my memory and attention seemed to work better and my productivity skyrocketed.
Exercise has literally transformed my life, and it can transform yours, too. Here I’ve shared with you some of the key findings about how exercise changes the brain’s anatomy, physiology and function.
1. It makes you happy.
Exercise boosts your mood in a number of different ways, including increasing the levels of the mood-related neurotransmitters serotonin and noradrenalin as well as the neurohormone endorphin, a natural version of morphine produced by the brain and associated with “runners high”.
2. It releases "feel-good" chemicals associated with pleasure.
The neurotransmitter dopamine has been associated with pleasure and reward. Dopamine is released in the brain when you fall in love, when you win a jackpot at the slot machines and … when you exercise. The dopamine release may also be related to that positive “addiction” some people experience with regular exercise that can lead to general crankiness when you don’t get your regular exercise “hit.”
3. It improves your attention span.
The finding in humans that's been replicated the most is that aerobic exercise enhances our ability to maintain and shift attention. Attention is a function dependent on the prefrontal cortex. In fact, just an hour of aerobic exercise has been shown to cause significant improvements in attention in people. It has also been shown that long-term increases in exercise enhance attention in people.
4. It's great for your brain.
Studies in rodents as well as in humans show that exercise can enhance the growth of new blood vessels in the brain (angiogenesis). Because the brain is the number one consumer of oxygen in the body, the more blood vessels in the brain, the more oxygen available to better help us do everything from thinking to seeing, feeling to moving.
5. It (literally) helps your brain grow.
There are only two types of cells in the brain: neurons and glia. While the neurons (brain cells) are the workhorses in the brain, glia are the support cells. Early studies showed that if you raise rats in “enriched” environments with lots of toys, large spaces to run around and other rats to play with, you could actually see the outer covering of the brain (the cortex) get thicker.
These changes in thickness were largely due to the birth of new glia cells. Like a muscle, a bigger brain is thought to be one with enhanced functions, with the additional glia cells are contributing to these improved functions.
6. It helps you sprout new synapses.
Synapses are the connection point where one neuron communicates with another. Studies in rats show that when they were trained on complex mazes requiring balance and motor learning, both the size and the number of synapses (connections between brain cells) increased in the motor areas of the rat brain. These new synapses are thought to underlie the increased amounts of motor learning taking place in these animals.
7. It boosts your memory.
Since the 1950s, we've known since that the hippocampus is important for memory. It was later discovered that the hippocampus is one of only two brain areas where new neurons are born in adulthood. This phenomenon is called adult hippocampal neurogenesis. With rodents, it was also found that exercise (in the form of a running wheel for rodents) can enhance the normal levels of adult hippocampal neurogenesis that results in better memory performance in rats.
8. Exercise increases the size of your hippocampus.
There's convincing evidence that aerobic exercise can increase the size of the hippocampus in the elderly. While a bigger hippocampus is thought to be a better functioning one, it remains to be shown that people with larger hippocampi due to exercise also perform better on memory tasks.
9. It can help you regulate your moods and beat stress.
An exciting new finding is that the hippocampus is not only important for memory, but is associated with regulating mood as well. Increased exercise can protect rats from the destructive effects of stress in the brain and it is thought that hippocampal neurogenesis plays a key role in this projective function.
10. It may build your imagination.
My favorite example of how exercise can change your brain is currently a possibility, rather than a given. It's recently been shown that the hippocampus is important for imagining future events. Patients with damage to the hippocampus are impaired at imagining possible future events and during brain imaging studies, the hippocampus is activated when subjects are asked to imagine possible future scenarios. These findings raise the intriguing possibility that enhanced neurogenesis in the hippocampus may not only improve memory and mood, but could enhance our imagination as well.