You’ve heard people going on and on about the physical effects of exercise, but what about the mental effects? Aífe McHugh looks at the neuroscience behind exercise.
MY housemate and I have started this “running” thing recently. We go out at dusk, listen to music or podcasts or the others’ cajoling for about half an hour as we go as fast as we can for as long as we can. It’s fun. It hasn’t been life changing so far.
Some of the physical effects are noticeable straight away; your heart rate increases, breathing becomes more rapid. Muscles pushed past their normal usage level start to ache, and when you stop you may keep breathing heavily for a minute as your body repays the oxygen debt to these areas. Oh, and depending on your personal biology, you might get sweaty and gross. Like I said, fun.
Over time, your body adapts. Muscles grow and strengthen with regular use. Aerobic exercise, like running, makes your heart and lungs stronger too. In the long term regular exercise reduces your risk of heart disease, bone disorders, and even some cancers.
Most of us know something about these physical effects. But what really keeps all those fitness freaks going are the psychological effects. They’re not as immediately noticeable as breathlessness, but they’re far more interesting.
“Aerobic exercise is literally the most effective stress management tool known to science”
The moment your body is doing more exertion than it usually handles, your endocrine system starts pumping out cortisol, AKA “the stress hormone”. Stress narrows and sharpens your focus to the task at hand. The combination of stress and activity then make your brain light up with glutamate, serotonin, and norepinephrine – which gives you that ‘buzz’ which sticks around for a while.
Most times you feel stress, you don’t get a fun buzz alongside it. That’s because most stressors in our modern lives aren’t physical challenges, whereas most stressors in the EEA, or Environment of Evolutionary Adaptedness (where modern humans evolved) were. Stress is meant to be something we switch on for a few minutes when there’s a lion chasing us. The act of exertion is the “off” switch. As our modern stressors are more likely to be stuff like essays and taxes, we can be stuck in a high stress state for most of the day, because your body doesn’t realise that this problem doesn’t need a fight or flight response (the autonomic nervous system can be a little dumb sometimes).
This is why aerobic exercise is literally the most effective stress management tool known to science. It’s like a reset button. The more you exercise, the more your body gets used to dealing with stress as a short lived, positive, and manageable thing.
“Exercise addiction, for one thing, is a serious disorder, which tends to coincide with eating disorders”
And that ‘buzz’ I mentioned up there? It helps regulate your mood, sleep cycle, and neurotransmitter activity. Thirty minutes of intense exercise a day strengthens your memory, focus, creativity, processing speed, self-control, problem solving skills … and so on. We’ve known for a while that exercise is extremely effective in the treatment of anxiety and mild to moderate depression (this doesn’t mean you should tell your mentally ill friends to throw out the pills and climb a mountain. Please don’t do that). It also helps alleviate the symptoms of ADHD and might also be helpful in the treatment of substance addiction, Alzheimer’s, and Parkinson’s.
It’s not all sunshine and roses, though. Exercise addiction, for one thing, is a serious disorder, which tends to coincide with eating disorders. You can imagine how dangerous that can be. Too much aerobic exercise does weird things to your heart, which makes you susceptible to circulation issues and stroke. Joints and muscles can be damaged by exercises which use ‘jarring’ motions, and lack of proper rest periods between exercise can cause muscles to weaken.
All in all, exercise is a very weird concept in the context of humans, bodies, and evolution. For most of human existence, physical activity was something that just happened, as we dodged predators and found food. The idea of taking time out of your day specifically to exercise is very new, and very local. Exercise seems very weird to people living in hunter-gatherer, or even unmechanised agricultural societies.
But you know what? Getting your 30-60 minutes a day really seems to be worth it. Even if you have to make your housemates join you…