Why does exercise have such a big impact on the brain?


If I go 3 days without exercising, I start experiencing brain fog and get depressed & more anxious. When I workout again, I gain mental clarity, become more motivated to take on the day, and like 75% of the self-deprecating thoughts I experience go away. Why does this happen to me? What’s the science behind this?

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When you exercise you get dopamine. Dopamine increases motivation. Dopamine makes you feel good.

biologically, exercise causes your brain to release neurotransmitters (most importantly dopamine and endorphins). neurotransmitters basically carry the chemicals that are used to trigger certain feelings, and distributes them throughout your brain.

that being said, endorphins can physically lower feelings of stress and pain and increase mood and energy. dopamine contributes to feelings of pleasure, reward, and satisfaction. exercise is among the healthiest and most natural ways to trigger the release of these neurotransmitters in your brain.

there are also a few much more simple ways that it could help clear up negative feelings.

for one, it feels good to be productive. exercise is productive. when you exercise, you might feel a sense of purpose. and fulfilling that goal gives you an immediate sense of accomplishment for how hard you’re working.

it also loosens your muscles that are probably otherwise tense from feelings of anxiety and depression while forcing you to breathe more steadily. this reminds your anxious brain that you are safe.

exercising gives you something healthy to focus on. it can interrupt your rumination and anxious thoughts, and refocus your energy onto something real. i think that’s a big reason why its clearing up the brain fog and anxiety for you.

Exercise (strength, endurance, etc) increases brain derived neuropathic factor (BDNF). This protein helps with brain cell survival (maintenance) and growth.

More exercise = more BDNF = more brain cell integrity

To add to other comments, something not touched on is why exercise causes the release of these neurochemicals (dopamine, endorphins, BNDF). As far as I know, we don’t know the answer to that question, but if someone does know, I’d love to learn.

Some of what works for me is a sense of accomplishment.

There’s a bike trail near my house which has mile markers on it, and the start, where it says “0.0” is just over a mile from my house. The first time I got to the other end, where it said “10.0,” I felt like I’d climbed Everest.

Sure, maybe sometimes I feel worthless, but in that moment, I had achieved something, and making it all the way back home left me feeling proud of myself. At a guess, most people can’t ride more than 20 miles after they turn 60.