Why Exercise Can Make You Happier: What Happens in Your Brain
by Nandita Kamalakannan
Have you ever gone for a run or finished a workout when you didn't really feel like exercising,
only to feel better afterward?
That feeling isn't just in your imagination.
Exercise doesn't only change what happens to your muscles and heart. It also changes what
happens inside your brain.
When we exercise, our heart rate increases and our body needs more oxygen. This causes greater
blood flow throughout the body, including the brain. But the interesting part is what happens
inside the brain as a result.
One of the best-known effects of exercise involves neurotransmitters. Neurotransmitters are
chemical messengers that allow nerve cells to communicate with each other.
Exercise can influence several neurotransmitter systems involved in mood, motivation, attention,
and stress.
One of them is dopamine.
Dopamine is involved in motivation, reward, attention, and learning. When you accomplish
something difficult during exercise—finishing a run, lifting a certain weight, or beating your
previous time—your brain's reward system can become involved.
That can make completing a challenging workout feel satisfying.
Another neurotransmitter involved in mood is serotonin. Exercise can affect serotonin signaling,
which is one reason physical activity is being studied for its effects on mood and emotional well-
being.
And then there are endorphins.
You may have heard people say that exercise releases endorphins. Endorphins are chemicals
produced by the body that can help reduce the perception of pain and contribute to positive
feelings during or after exercise.
But the story doesn't end there.
Exercise can also affect a protein called brain-derived neurotrophic factor, or BDNF.
BDNF helps support the growth, survival, and function of neurons. It is involved in processes
related to learning and memory. Physical activity can increase BDNF signaling, which is one
reason researchers are interested in the connection between exercise, brain health, and cognitive
function.
Exercise also interacts with the body's stress system.
When you're stressed, your body activates systems involving hormones such as cortisol. Exercise
itself is a physical stressor, but regular physical activity can help the body adapt to stress and
may influence how the stress-response system reacts over time.
This may help explain why going for a run after a stressful day can sometimes make your
problems feel a little more manageable.
There is another connection between exercise and the brain that teenagers should probably care
about: sleep.
Regular physical activity is associated with better sleep for many people. And sleep is extremely
important for the brain because it supports memory, learning, emotional regulation, and recovery.
So exercise can potentially create a cycle:
You exercise.
Your body and brain respond.
You sleep better.
Your brain gets time to recover and process information.
You may feel better the next day.
And then you're more prepared to be active again.
Of course, exercise isn't a magic solution for every emotional problem. Feeling sad, stressed, or
anxious is a normal part of life, and serious or persistent mental-health concerns deserve support
from trusted adults and health professionals.
But there is something pretty amazing about the fact that moving our bodies can affect our
brains.
We often think of exercise as something we do to become stronger, faster, or healthier physically.
Maybe we should also think of it as something we do for our brains.
The next time you put on your running shoes, go for a walk, ride a bike, or play a sport,
remember that you're not just training your muscles.
You're giving your brain a workout too.
Works Cited
"Benefits of Physical Activity." Centers for Disease Control and Prevention, 4 Dec. 2025,
www.cdc.gov/physical-activity-basics/benefits/ .
"Neurotransmitters: What They Are, Functions & Types." Cleveland Clinic, 14 Mar. 2022,
my.clevelandclinic.org/health/articles/22513-neurotransmitters .
"The Ultimate Brain Booster: Exercise and Mental Health." Stanford Lifestyle Medicine, 1 May
2024, lifestylemedicine.stanford.edu/the-ultimate-brain-booster-exercise-and-mental-health/ .