What is the Nervous System, and How Does it Play a Crucial Role in Your Workouts?
Every squat, sprint, lift, and burpee starts long before your muscles move – it begins with your nervous system, firing signals milliseconds ahead of any conscious thought1.
But what is the nervous system – and why does it matter so much to your training?
The nervous system is your body’s way of sending messages between your brain, spinal cord, muscles, and organs1. Without it, you couldn’t move, react, balance, or recover1. In an F45 workout, the nervous system is firing constantly – choosing which muscles to work, keeping you coordinated, and matching your heart rate to the effort2.
In this article, we’ll be breaking down what the function of the nervous system is – from the central and peripheral systems to the autonomic, sympathetic, and parasympathetic branches – so you can understand the system behind every movement you make.
What is the nervous system?
The nervous system is your body’s communication network – it carries messages between your brain and the rest of your body, so they work together in real time1.
Using electrical and chemical signals, your brain reads information coming in from your muscles and senses, then fires instructions straight back out1. Right now, as you read this, it’s firing thousands of signals a second – moving your eyes across the page, holding you upright in your chair, and keeping your heart beating.
What is the function of the nervous system?
To understand what the function of the nervous system is, picture a constant loop: it gathers information, makes sense of it, and directs your body to respond – keeping you moving, feeling, and alive. During a workout, that loop is what lets your body:
- Coordinate movement – timing dozens of muscles together so your body moves as one. It fires them in the right order and holds back the ones that aren’t needed, so a lunge, a burpee, or a clean-and-press flows as a single smooth action.
- Maintain balance and posture – constantly making tiny adjustments, like steadying you on one leg in a split squat or keeping your spine stacked and stable while you hold a plank.
- Regulate heart rate, breathing, and temperature – reading how hard you’re working and adjusting to match, lifting your pulse to pump more blood to your muscles, deepening your breath to pull in more oxygen, and making you sweat to keep you from overheating.
- Adapt and recover – recruiting more muscle fibers as you fatigue to keep you going, then slowing your heart rate, and breathing as you begin your cool-down.
Ready to put your nervous system to work? Find your closest F45 studio and start a trial today.
What is the central nervous system?
Your central nervous system (CNS) is your brain and spinal cord – the control center where every decision gets made1. It takes in information from all over your body, works out what needs to happen, and sends the orders out1.
What is the peripheral nervous system?
Your peripheral nervous system (PNS) is the delivery network connecting your CNS to the rest of your body – every nerve branching out beyond your brain and spinal cord1.
The PNS carries information both ways: picking up signals from your body to send inward, then delivering the brain’s instructions back out1. The peripheral nervous system splits into two branches, each handling a different kind of job: the somatic nervous system runs the movements you choose to make, and the autonomic nervous system runs the background processes you never have to think about3.
Below, we explain what the peripheral nervous system is in more detail.
What is the somatic nervous system?
The somatic nervous system controls voluntary movement: activating your skeletal muscles and carrying out every exercise you consciously choose to perform3. When you press a barbell overhead, it’s the somatic system carrying that command from your brain to your arms, firing the right muscles to push the weight up.
What is the autonomic nervous system?
The autonomic nervous system controls the functions you rarely have to think about – including breathing, heart rate, and digestion3 – adjusting them automatically to maintain your body’s internal balance (known as homeostasis).
Sweating is a perfect example of your autonomic system at work: as you heat up mid-workout, your body starts sweating to cool you down.
The sympathetic vs parasympathetic nervous system
We’ve covered what the autonomic nervous system is – but it doesn’t stop there. It splits into two separate systems: sympathetic and parasympathetic. One winds your body up to perform; the other winds it back down to recover4.
Read on as we explain each side, and how they work together to help you train hard and recover well.
What is the sympathetic nervous system?
The sympathetic nervous system activates your body’s “fight or flight” response – the ancient survival reflex that primes you to act fast under stress4.
Your body can’t tell the difference between sprinting from danger and sprinting an interval, so it responds to a hard workout the same way by:
- Increasing your heart rate4
- Delivering more oxygen to your muscles4
- Redirecting blood flow towards the muscles doing the work4
- Heightening your alertness4
It drives all this by releasing adrenaline and noradrenaline – your body’s natural accelerants. Rather than holding you at your resting baseline, it shifts you up a gear to meet the demand, a process known as allostasis. It’s the surge you feel as you brace for a heavy lift or push through a final sprint.
What is the parasympathetic nervous system?
The parasympathetic nervous system is the opposite side of the coin, often called the “rest and digest” system because it takes over once the effort stops and steers your body back towards calm by4:
- Slowing your heart rate4
- Encouraging digestion4
- Directing energy towards repairing and rebuilding muscle4
Cooling down, stretching, and slow, controlled breathing all help flip the switch from “fight or flight” into “rest and digest”. Your body does most of its repair and muscle-building during post-workout recovery, when the parasympathetic system takes over.
Incidentally, this is exactly why rest days are important – as they give your body the time it needs to turn your hard work into results.
How F45 workouts challenge your nervous system
So, what is the role of the nervous system in your workout?
Your nervous system controls every movement you make – and every movement trains it right back2. F45’s functional exercises and metabolic conditioning push that relationship, challenging your brain to coordinate your body and hold control.
As F45 athlete Nic Wilson explains: “We associate being fit with lifting heavy and running fast, but what I notice in our members is their coordination, their balance, how naturally the movements come – and that’s all coming from the nervous system.”
Now, read on as we explore the connection between exercise and the brain in more detail.
Resistance workouts
Our resistance workouts build strength through controlled, repeated movements like squats, presses, and deadlifts. As Wilson describes: “We use progressive overload – adding a little weight or a few more reps each session, so you’re always challenging your muscles.”
As you lift heavier, your nervous system learns to recruit more muscle fibers and fire them in tighter coordination. It’s why you can often lift more within just a few sessions, before your muscles have visibly grown – your body has simply gotten better at using the muscle you already have2.
Cardio workouts
Cardio workouts get your blood pumping and make you breathe faster, calling on your nervous system to push more oxygen to your muscles and brain.
As Wilson details: “Expect to be challenged. Our cardio workouts are built to grow your stamina and improve your running endurance through sprints and explosive plyometric movements, all driven by timing and tempo.”
That extra oxygen keeps you sharp as well as moving – helping you hold your form, react quickly, and make good decisions even as fatigue sets in2.
Hybrid workouts
Hybrid workouts blend strength and cardio into a single session, so you’re constantly moving between very different demands.
As Wilson continues: “It’s cardio and HIIT in one – a strength station with dumbbells or a barbell, straight into cardio bursts on the bike or rower, then balance and bodyweight work. You’re never doing the same thing for long, so your body’s always adjusting.”
Every switch between movement patterns forces your nervous system to adapt – and with practice, that sharpens your reaction time and helps you pick up new movements faster2.
Now that you understand what the nervous system is, why stop there? Learn about the connection between hormones and weight loss – and discover how dopamine and endorphins work in your body.
1 https://www.ncbi.nlm.nih.gov/books/NBK542179/
2 https://www.ncbi.nlm.nih.gov/books/NBK482280/
3 https://pubmed.ncbi.nlm.nih.gov/37170957/
4 https://pmc.ncbi.nlm.nih.gov/articles/PMC7987796/
Written and published by F45 Training HQ, and reposted here for the F45 Morris Plains community.
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