HOW DOES EXERCISE AFFECT THE BRAIN?
I was walking into the gym yesterday when I suddenly realized how good I felt. My feet felt firm and strong on the pavement as I took sure strides across the parking lot, my posture was erect, and I felt calm, but energized and purposeful. I also noticed a sense of confidence within myself -- of competence and capability -- that I didn't feel even a few days ago. And underneath my skin, my muscles felt like they were humming.
I think I'm like a lot of people in that I tend to go through long periods of regular exercise, only to fall out of my routine for a month or two. I got back on the proverbial horse a few weeks ago, so I'm not surprised I noticed a change in the way I felt. I'd describe it as my "working out feeling," and it's a major motivator behind my healthy lifestyle. When I feel this way, I find myself making positive choices that reach far beyond how often I move and what I eat. I speak my mind more thoughtfully and more often, I'm more patient, productive, and detail-oriented. I generally feel like I'm more together when I'm active. But where is this feeling coming from? It's more than feeling confident in the way I look and what my body can do, and certainly deeper-reaching than the well-reported endorphin response we get from exercise. So I decided to investigate, and here's what I discovered:
It's all about the neurotransmitters. The much-hyped endorphins are just one of the chemical messengers the brain releases during exercise. Working out also gives us such a potent boost in serotonin that psychologists often prescribe exercise to help treat patients suffering from anxiety and depression. But perhaps what interested me most is the release of two neurotransmitters that have seemingly opposite effects. According to a recent article on Huffington Post:
The brain releases dopamine and glutamate, too, to get those arms and legs moving, as well as gamma-aminobutyric acid, or GABA, a prohibitive neurotransmitter that actually slows things down, to keep you moving in a smooth and controlled manner.
That would explain the feelings of control and quiet motivation I was experiencing. But the thing is, I was on my way into the gym. So why was I already feeling so good?
Blood flow. It turns out the increased blood flow that results from an elevated heart rate also benefits the brain. As the heart drenches the body with oxygen to replenish tired muscles, the brain also gets a boost of O2. This supports the creation of more brain cells -- cells which don't die even if you ditch your exercise routine. In fact, a study at the University of British Columbia found that exercise actually prompts growth in the hippocampus -- the part of the brain associated with learning and memory. And an Irish study found that participants were able to improve their scores on memory test after 30 minutes of cycling, while a sedentary control group saw no such improvement. Even better: the increased blood flow prompts the brain to turn certain genes on and off, which could be why regular exercise can help ward off demential and Alzheimer's disease.
More brain benefits. The deeper I dove, the more science I found to back up the way I felt. For example, a reporter for Fast Company worked out for a month to see if she noticed a change in her overall mental health. Before starting her experiment, she consulted clinical exercise physiologist Dr. Bill Sukala, who told her that -- in addition to warding off diseases of the brain, treating psychological illness, and promoting the growth of new brain cells -- it can also help control the stress hormone cortisol, improve our ability to think clearly and logically (hence my sense of focus and productivity), and help control the collateral damages done to the brain by other diseases like diabetes.
Distance runners may know something the rest of us don't. Imagine this: three groups of rats are participating in a study in Finland. One group is doing BBG (or an equivalent high intensity interval training workout), another is lifting tiny weights while saying the word "bro" every two squeaks, and the third is on a Forrest-Gump-style distance run. While I may have slightly embellished the scenario, I'm referencing a real study. And that research found that the distance-running rats saw big time growth in the hippocampus, while the resistance training rats saw none and the HIIT rats' results were negligible. (Although their abs looked fantastic.) While more research is needed, this suggests that straight-up cardio may be best for hippocampal growth.
Maximize your exercise to get the most benefit. Despite the Finnish fitness rats' results, experts agree that a balanced approach to exercise containing HIIT, cardio, and weight training is likely best for brain health, and that regular, daily exercise regardless of duration can reap major benefits for overall wellness.
Where they disagree is on what time of day we should be hitting the gym. For example, many experts will tell you to work out first thing in the morning to help create alertness and boost your energy. However, competing research suggests that our circadian rhythms make us strongest and most resistant to injury between 2 and 4pm, which would make that the best time to work out.
Personally, I don't know anyone who can build their schedule around their workouts. Like most people, I fit it in wherever I can: whether it's at 5am before my son wakes up, or a quick 5pm session after work. The key is consistency because while the way I feel may not be scientific, I know I lose that "working out feeling" if I don't move my body at least five days a week. And that's evidence enough to keep me motivated.