What Exercise Does To The Body
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Exercise does many things to the body. It acts on and improves the skeletal system, the neuromuscular system, the cardiovascular system, the respiratory system, as well as our overall health and its various components. Even the brain and the very cells of our body are aided by exercise.
What Exercise Does To The Skeleton
There are both short and long term benefits to the skeleton from exercise.
Reduces Wear And Tear On The Joints
There are 3 types of joint: fixed (such as those joining the bones in the skull), cartilaginous (the vertebrae of the spine), and synovial (everything else).
Synovial joints come in various forms, like ball and socket (hip and shoulder) and hinge (knee and elbow), but regardless of the type of synovial joint we’re talking about, they all have the same structure.
One such part of that structure is a cavity. The cavity is surrounded by a membrane, and this membrane secretes fluid into the cavity during movement. The purpose of this fluid is lubrication, and the purpose of this lubrication is to reduce wear and tear and allow it to move more freely.
This is one of the reasons why warming up (both muscles and moving joints through their range of motions) before exercise is advisable. Not having lubricated joints before high impact occurs, especially if done regularly and over the long term, will quite likely lead to joint problems.
Increased Blood Flow
Increased blood flow means increased nutrient delivery. So basically a happier and healthier skeleton.
Improves Range Of Motion (ROM)
Moving joints through their range of motion increases the range of motion of that joint, especially the ease with which a range of motion can be achieved.
It’s perhaps easier to notice this by considering the opposite, such as not moving joints through a range of motion inhibits your ability to move those joints through that range of motion.
For instance, consider that you’ve been sitting down and hunched over for a large portion of the day, or bent over at a less than ideal angle for a protracted period. From such positions you’ll often find yourself feeling ‘stiff’ and having difficulty with, for example, squatting or straightening your back.
It’s your lack of movement that has reduced your range of motion here. Moving your joints through these ranges of motion, such as squatting or straightening your back, brings back your ability to perform these movements easily and painlessly.
Improves Range Of Motion (ROM)
Exercise also improves the range of motion over the long term, which itself improves your flexibility. Maybe you’ve got a stiff elbow or knee and find it bothersome or painful to straighten, or even unable to straighten.
However, if you persevere with routinely straightening these joints then your chances are good that you’ll be able to straighten them eventually and be pain-free with it.
Likewise with squatting. Even some people in their 20’s can no longer squat (which is a little shocking, to be honest), even though squatting is something that humans have been doing for millennia.
In the majority of cases, the reason people can’t get down into a squat position is that they’ve been limiting the range of motion of their hip for too long.
The long and the short of all this is that if you move joints through a range of motion then a greater range of motion will develop.
This is largely a consequence of an increased range of motion and neural programming (the relative activation of your muscles), which are both improved through exercise.
Maintaining a good range of motion in the shoulder girdle and scapula, for example, can offset the rounding of the shoulders and the hunching of the back (hyperkyphosis).
Maintaining a good range of motion in the hips (hip flexor, piriformis, etc) can help prevent pelvic tilt (such as with hyperlordosis) and lower back pain.
Although the concept of ‘an ideal posture’ is something of a misnomer because individual anthropometry is pretty unique for each individual (and lifestyle and how you habitually hold yourself are certainly the largest factors influencing posture), exercise can certainly point you in an improved direction due to increasing the range of motion of your joints and improving the neural programming of your muscles.
Increased Bone Density And Strength
Stressing your frame forces the frame to adapt to the stresses. Technically, your body ramps up ossification (bone formation) by removing old bone and depositing new bone.
Although stressing the frame for increased density and strength is more potent in our formative years (pre 25) and sets the skeleton up for being hard and strong throughout life, it’s still beneficial at any age since ossification happens throughout our entire lives.
For sure, age causes calcium to be continually lost from bone, thereby reducing its density and strength (in real terms) as we age. But this consequence of ageing can be pushed back against and delayed by making the skeleton experience stress and force.
The result is denser and stronger bones for longer, which reduces the risk of osteoporosis, which reduces the risk of fractures.
Improved Cartilage Health
Use it or lose it, as the saying goes. Making the cartilage do its job is the route to ensuring they stay healthy and are continually able to do their job. Running, for example, is not bad for the knees; it promotes healthy cartilage.
Of course, too much stress could certainly have the opposite effect, such as with ageing powerlifters or extreme distance runners—perhaps even more likely if they ramp up too fast and don’t allow enough time for necessary adaptations to take place—and some sports (like skiing) certainly appear harmful to joints.
But this is generally a consequence of excessive body punishment, often for performance and competition purposes, not exercise for health purposes.
Increases Joint Stability
Exercise strengthens the ligaments (the things that attach bone to bone) and tendons (the things that attach muscle to bone) that surround our joints, thereby increasing the stability of the joints themselves.
Ligaments and tendons strengthen much slower than muscles. This is likely the main reason why you see those on performance-enhancing drugs tearing their muscles during bouts of heavy lifting. Something very unlikely to happen to a natural lifter, especially if they’re not incredibly strong.
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Of course, various other things can affect our skeleton and bone formation. Nutrition being a hugely important and obvious one. Moreover, this is not only good nutrition that ensures you’re fuelling your skeleton with what it needs to grow, develop, and be strong, but also nutrition that doesn’t inhibit its growth in the first place.
Calcium, for example, is very important for the skeleton, but calcium absorption can be inhibited through various means (such as excessive alcohol, caffeine, or carbonated drinks). Likewise with sunlight. Vitamin D is essential for the proper absorption of calcium.
Inhibiting calcium absorption will lead to the bone matrix being deficient in calcium, which could lead to weak or deformed bones.
A properly functioning endocrine system (your hormones) is also essential for proper bone formation. In children, this is growth hormone. In adults, it’s testosterone and oestrogen.
But exercise and stressing our frames does wonders for the skeleton and pushes back against the effects of ageing, so don’t look upon exertion as a punishment. Instead, seek it out and maintain your youth for longer.
What Exercise Does To The Neuromuscular System
The Neuromuscular System—A Primer
The neuromuscular system comprises all of our internal and external muscles as well as the nerves connecting them.
Nerves (or neurons) are the transporters of messages, which travel down the neuron to the neuromuscular junction. The neuromuscular junction is where the messages enter the muscle fibres.
And the whole thing, the nerve, the neuromuscular junction, and the muscle fibres it’s connected to, is called a motor unit.
How many muscle fibres a motor unit is connected to depends on the site and purpose of the muscle, with motor units involved in more dexterity of movement (such as the hands) being connected to fewer muscle fibres than those involved in power and strength (such as the shoulders and glutes).
The motor units involved in the movement and control of the hands might be connected to 10’s of muscle fibres, whereas those in the glutes might be connected to 1000’s.
How your neuromuscular system develops will largely depend on your individual makeup.
For instance, maybe you have a higher degree of fast-twitch muscles in your legs, so are well suited to excelling at strength and power work (like sprinting).
Conversely, maybe you have a higher degree of slow-twitch fibres in your legs, so are well suited to excelling at endurance and fatigue resistance work (like marathons).
Most likely though, you’ll just be average, and so are well suited to being a pretty good all-rounder but not well suited to becoming top of the world’s rankings in something.
Like most of the body’s adaptations to exercise, the changes, and the degree of them, often depend on the exercise being performed. Endurance work will mainly develop the muscle’s aerobic capacity whereas strength and resistance work will mainly increase their size, but here are the general adaptations from exercise.
Increases Resting Energy Expenditure
This is largely due to an increase in muscle mass because muscle is a costly tissue, and the more muscle you have the more energy is required to maintain it.
Muscle is so costly that if you don’t use it and demand output from it then the body will just get rid of it. It’s such a large drain on resources.
It’s why you or I might be able to maintain our weight and physique on 2000–2500 calories a day, but yet a bodybuilder who is the same height as us might require 3000–3500 calories a day. The additional calories are required to maintain their extra muscle.
This isn’t a given, and exercise can pervert posture if you don’t do it right.
For example, if all you do is train the ‘mirror muscles’ (biceps and chest), then you’ll probably end up developing a worse posture because the increase in chest muscle will eventually start pulling the chest in and rounding the shoulders, which will (often) lead you to round your upper back also.
To prevent this (and actually improve your posture) you want to train opposing muscle groups. Such that if you train your chest be sure to also train your back.
The idea is balance, and if you train correctly and for health (and not the mirror) your posture will nearly always improve through exercise.
Increased Glycogen Stores
Glycogen is an energy store around the muscles. It’s percentage-based, so the more muscle you have the more glycogen stores (in energy terms) you have.
Increased glycogen stores means you can store more energy. So not only can you eat more before gaining fat but you’ll also have increased muscular endurance.
Improves Motor Unit Recruitment
Basically, the more you call upon a muscle the more adept you become at calling upon that muscle. This allows you to generate more force (and get stronger).
Improvements In Skill And Motor Related Fitness
Exercising and calling upon muscles causes an increase in neuromuscular connections, which, as with the motor units, makes you more adept at using and calling upon your muscles.
Improvements in skill and motor-related fitness will lead to improvements in things like coordination, balance, reaction time, agility, and power.
Increase In Size And Number Of Capillaries Surround The Muscle Fibres
Bigger and more capillaries serving the muscles means higher blood flow, which means higher nutrient and oxygen delivery and therefore healthier muscles. The increase in blood flow will also speed up recovery.
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Muscle is so good for us for so many reasons that we should all be looking to maintain a decent amount of lean tissue to keep us healthier and independent for longer. Muscle is hugely important for all things involving movement and bearing loads. From carrying the groceries, to getting yourself out of a chair, to not falling over.
What Exercise Does To The Cardiovascular System
Over the short term, some of the effects of exercise look as though exercise is something we should be avoiding. Indeed, exercise doesn’t look good at all in the short term: increased heart rate, blood pressure, free radical production, inflammation. All things we’d say are taking us away from health, not towards it.
However, as with many things physiological, short term effects are not indicative of long term outcomes, and it’s in the long term effects of exercise that we should be paying attention.
There are 4 benefits of exercise on the cardiovascular system over the long term, and they all work together and in tandem to bring about an overall increase in health.
Increase muscle growth of the left ventricle.
Increased aerobic capacity.
Increase in size and elasticity of arteries.
Decreased resting and working heart rate.
Basically, the left ventricle of the heart (the chamber that pumps blood around the body) gets stronger so it can deliver more blood per beat.
This, along with higher oxygen intake and increased size of arteries, increases our aerobic capacity—we’re transporting and delivering more blood and oxygen with each beat of the heart, which increases performance and recovery. Higher blood supply also means more able cooling, which keeps performance up.
And all of this works together leading to a decreased resting and working heart rate.
Basically, your body is working better and, colloquially, you’ve got ‘fitter’.
Normalised Blood Pressure
A further result of this is a normalisation of blood pressure. This further increases cardiovascular health by allowing the heart to work more easily, which leads it to experience less strain.
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In essence, exercise (most notably aerobic exercise) keeps the heart strong, keeps the arteries clear and supple, and keeps blood pressure down.
What Exercise Does For Health
The definition of health depends on where you get it from. The WHO, for example, defines it as “complete physical, mental, and social well-being, and not merely the absence of disease or infirmity”.
There are also different components to health:
Mental & Emotional Health.
This is easy enough to understand and is basically what we’ve been covering in this post on what exercise does to the body. Physical health covers all of the body’s systems, including the heart, lungs, muscles, bones and joints.
It’s generally broken down into health-related components, like cardiovascular fitness, muscle strength and endurance, flexibility, etc., and skill-related components, like balance, coordination, reaction time, agility, etc.
Exercise benefits all of this, but the degree to which it benefits any one specific component depends on the type of exercise being performed. Resistance training can benefit muscle strength and endurance and aerobic exercise can benefit our cardiovascular fitness.
Mental & Emotional Health
Whether we’re talking about the short term effects of exercise gained through the release of a wide variety of chemicals (the 4 most prominent being endocannabinoids, endorphins, dopamine and serotonin) or having powerful effects for improvements in general mental health and stress, depression and anxiety (studies here are numerous, but here’s a few: 1, 2, 3, 4, 5,), reducing the risk of neurodegenerative diseases, or aiding with sleep, exercise has many potent advantages for the brain.
Exercise has a wide variety of beneficial effects in regards to our medical health, from greatly reducing the risk of atherosclerosis to improving body composition in respect of fat mass (both prevention and relapse).
It helps with metabolic syndrome, reduces the risk of several cancers (1, 2, 3, 4, 5, 6,) and chronic disease in general, as well as seemingly slowing the deterioration of the immune system as we age (1, 2, 3,).
Nutritional health can even be improved through exercise as a somewhat secondary effect.
Those who exercise often improve their nutrition due to wanting to take full advantage and reap the benefits and adaptations that exercise forces the body into. After all, if you don’t eat right then your body doesn’t improve as good as it could.
Common examples would be improvements in the quality of protein to assist with new tissue (muscle) generation as well as improvements in fibre intake to assist in improvements in body composition.
Those who exercise and incorporate it into their lifestyle will often take it upon themselves to learn (at least the basics) of nutrition and macronutrients, as well as how to appropriately use food for their purposes.
Knowing what’s what is the first, and arguably the most important, step to improving your nutrition.
This can be improved by exercise through 2 main routes:
It can make you feel good, which allows you to interact better with others. It can also improve your confidence (through things like a sense of achievement, emotional well-being, appearance, attention and concentration, among other things), which allows you to function better in social settings.
Depending on the exercise you take part in, the act itself can be a social experience (which can further help with confidence).
Granted, gym-goers can sometimes seem anti-social, especially at the time of the exercise because they’re focused on their routine and the exercise they’re currently doing. But going to the gym with a friend turns it into a social experience.
Further, gym-going is not the only route to exercise. Sports, for example, are mostly very social experiences. And sports, assuming your body is up to it, are generally excellent forms of exercise.
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In the final analysis of what exercise does to the body, the answer is a whole lot of good!
We’ve been covering the board strokes here, and quite literally a book could be written on the topic. And while that would certainly be interesting from an academic point of view, convincing people of the benefits of exercise is not all that difficult. What’s difficult is getting them to do it.
With regards to the former, we hope we’ve convinced you of some of the beneficial results of exercise. The sources we’ve used are of course authoritative, but bear in mind that there are hundreds of good studies linking exercise to improvements in the various components of health. Hundreds! The ones linked here are, basically, just the ones that we chose to (somewhat randomly) pick out the pot.
We haven’t even covered things like massively improving glucose control, lowering inflammation, adjusting hormone levels beneficially, pushing back against (and even preventing) cellular senescence (the ageing of cells, through various means), and improving cognition.
No reasonable person can deny the overwhelming evidence of the powerful, health-promoting effects of exercise.
And in an attempt to assist you in the latter point, make no mistake, exercise is one of the very best things you can do for your overall health (especially over the long term).
Not only will exercise make you and your body more adept at (basically) everything in the here and now, it will also help you keep your vigour into old age by strengthening the skeleton, maintaining high aerobic capacity (cardiovascular and respiratory), avoiding debilitating muscle loss, and promoting the upkeep of basically every system in the body.
Conversely, and given that we never evolved to function optimally without lifelong physical activity, not exercising will see nearly all our systems enter a state of degradation, starting in our early 30’s.
Exercise, quite literally, has anti-ageing benefits and reduces our risk of mortality and morbidity across the board. In fact, if there was only 1 thing you could do to improve your health, then exercise, from a quantitative perspective, should be the thing you choose to do.
Couple exercise with other lifestyle factors, such as not smoking, not being obese, having good relationships, getting good sleep and healthy nutrition and you’re giving yourself the very best chance you can!
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Before we leave you, it’s probably worth touching on a nagging question you may have. That of “okay, great, so I know what exercise does to the body, but what exercise should I be doing?”
While this question can seem important, it’s really not. What’s important is that you exercise. Only after you’ve established an exercise regime and incorporated it into your life should you be concerned about what exercise you should be doing.
If you’re not currently someone who exercises then your thoughts should be concerned with finding something that you enjoy and that’s rewarding. Whether this is a physical reward (performance, aesthetics, etc.) or an emotional reward (social, elevated mood, etc) is not as important as there being a reward in the first place.
When you’ve got exercise into your life regularly you can start considering the specific benefits of the different types of exercise. At which point, your wishes, wants, and reasons will inform you on whether you should be doing exercise X or exercise Y.
Generally speaking, aerobic exercise has more of the direct anti-ageing benefits and resistance training has more of the mobility benefits.
But regardless of how you weigh the benefits of each type of exercise, from a pure health perspective, you should be doing both aerobic exercise and resistance training.