Health and medical experts like to talk about the ripple effects of exercise: improved muscle tone, a stronger heart and lungs, and healthier joints. But an under-appreciated, and very rewarding, benefit of training is its effect on our brain and general nervous system. So what effect does exercise have on the nervous system? Find out!
The benefits of exercise for your nervous system
We know all the ways exercise can benefit us in terms of strengthening our bodies and improving our health, but it helps our nervous system in a few ways.
1. Helps you relax
The autonomic nervous system — the mechanism responsible for ramping you up for action and cooling you down afterward — gets a nice workout every time you exercise:
- When you start your workoutYour body briefly ramps up the sympathetic “fight or flight” system: your heart rate increases, digestion slows down, and pain sensitivity decreases.
- After your workoutHowever, your body settles into a relaxed, parasympathetic state: blood vessels dilate, breathing and heart rate slow, and digestion resumes.
- Over time, research suggests that heart rate variability (HRV) increases when your body responds well to both sets of inputs (parasympathetic and sympathetic signals). A low HRV means that one system is dominant. Exercises are shown to help the ability to communicate effectively in each system.
2. Nerves keep you guessing — and growing
Exercise makes you think: “Especially when you’re just starting out, exercise is a form of learning,” says Angelo Poli, ISSN, creator of the MetPro app.
Strength-training moves like squats, lunges, and rows, as well as cardio moves, like trail running and dancing, involve lots of muscles, dozens of joints, and thousands of miles of neural connections. In addition to stimulating the muscles, exercise also stimulates the nervous system, which can make work more enjoyable.
“Nerves crave novelty,” Polly says. You may feel awkward after working out or dancing or playing basketball for the first time, but your nervous system lights up from the new stimulus and you’re probably in a better mood for it. With practice, you gain fluency and proficiency in your new activity.
Repetition of the same movement becomes less stimulating over time. This is one reason why you should regularly change your routine and expose yourself to new and different activities as your fitness increases.
The difference doesn’t have to be huge. Even changing from a reverse lunge to a rolling lunge or running on a trail or hill over a flat surface stimulates new muscles and new learning. Changing the speed of your movement — lifting faster and lowering slower, for example — places a different demand on your nervous system, stimulating learning and growth.
Can exercise have a negative effect on the nervous system?
Exercise is a form of stress. However, if you do it right — enough, but not too much, with adequate recovery — you’ll stimulate growth not only in your muscles, bones, and connective tissue, but also in your nervous system.
Extreme exercise, however, can have the opposite effect. A 2019 study of triathletes suggests that significantly increasing the amount of weekly endurance exercise leads to “brain fatigue” and poor decision-making. Taken to extremes, exercise not only destroys athletes’ bodies, but also their brains.
This only seems to happen in extreme cases, though. On a more rational level, exercise is a balm for the nervous system and a brain-enhancing activity.
What does science say about exercise and its effects on dopamine levels?
Something to remember when you’re thinking about skipping a planned workout: Exercise gives you a healthy hit of dopamine. Feel-good hormones associated with joy, motivation and hope are part of why we feel more optimistic and charged-up after a vigorous gym session.
Exposure to these mini-dopamine spikes over time rewires your brain’s reward system. More dopamine circulates through your system and your system simultaneously becomes more sensitive to circulating dopamine. This makes exercise an effective mood-booster, both in the short and long term.
How does exercise help fight fatigue?
You might think that expending energy through exercise will tire you out, but in fact, the opposite is true. A recent study highlights what trainers and regular exercisers have known for a long time: working out reduces fatigue.
Studies have shown this to be true in many populations, including healthy adults, cancer patients, and people with diabetes. All of them found that exercise alleviated feelings of fatigue and made them more alert.
How does it work? Researchers theorize that exercise-induced increases in norepinephrine, serotonin, and dopamine (again)—three energizing neurotransmitters that relieve fatigue and increase energy in animal studies—are responsible for these responses in humans.
“When you’re completely sleep deprived, exercise won’t help you much,” says Polly “But if you’re just feeling lazy, a workout might be all you need to turn it around.”