We all heard countless times about the benefits of exercising and experienced it at a certain time, so it’s pointless to repeat it over and over, it won’t have that good of an impact. That’s why today we’re going to discover step by step how your body is changing with regular exercise, you’ll be amazed to see things this time from a different perspective and I’m pretty sure you will be motivated more than ever.
The key thing to remember is ‘Regular’ because the changes which we’re gonna discuss require persistence. Also, we are going to take for an example, an adult sedentary male who exercises occasionally.
During the first workout after a long period of inactivity:
Your heart rate starts accelerating gradually pumping more and more blood and increasing the cardiac output to provide your organs with more oxygen, your breathing rate increase alongside with every heartbeat.Your VO2 also called maximal oxygen uptake isn’t a good as an athlete so you will not have the best endurance.
Your muscles are now well nourished and they consume more nutrients for energetic and growth purposes.
After a while, Lactic acid begins to build up quickly due to the depletion of glycogen(long chains reserves of glucose) in your liver and muscles.lactic acid is a final product of anaerobic energy consumption, you will feel fatigue and pain accumulating but you will survive eventually.
If you continue anyway for a long period without any carbs intake, you could enter the Ketosis state where your body turn fats into ketone bodies for energetic purposes until you stop exercising.Ketogenic state happens when your glucose levels are low, fats are transformed to ketone bodies in your liver and they are now used instead of glucose, your heart and brain are the biggest consumers of these metabolic resources.
Now you are tired, you need to sleep and your body is completely useless, what the hell is going on?
Researchers have found that acute exercise stimulates the production of melatonin.If you don’t know what’s melatonin, it’s a hormone produced by a special gland called the pineal gland found in the center of the brain.
Its main action is regulating the circadian rhythm, in fact, the levels of melatonin increases throughout the day and they are very affected by the Light cycle(Ref3).Computer and cell phones emit more blue light than normal exposure, the result is a disturbance in the circadian rhythm and regular exercise can get rid of this problem.
Your cognitive functions are slightly improved, a study found that people who perform cognitive activities after short-term exercise are able to concentrate better, memorize better and perform better than people who didn’t work out before the tests (Ref2)
The Day After:
When you wake up you feel pain in all the muscles of your body, it’s like a burning or stiffness sensation. You probably experienced that feeling, it’s actually a medical condition called Delayed onset muscle soreness or simply DOMS. It appears after 24 to 48 h of a workout and lasts for 1 or 2 days.
This chart shows approximately the evolution of DOMS in the following 120 H, but things differ from a person to other.The next time you workout, you won’t feel as much pain as the first time, but why?
Different theories tried to explain this phenomenon but neither one of them is perfect.For a long time, we thought that the microlesions of muscle fibers triggers an inflammation response explaining the pain and as the muscles fibers adapt by increasing their number and volume, the same physical activity won’t have the same effect as the last time and the inflammation is decreased.But in 2015 a study found that inflammation markers don’t drop after a regular exercise, they can even increase! This suggests that workout soreness is not caused by inflammation itself but by something else that inflammation actually prevents (Ref4).Other theories include enzymatic changes and neurological adaptability, we still don’t know what triggers DOMS and usual treatments such as massage and anti-inflammatory drugs aren’t that effective but still, DOMS isn’t harmful and disappear in few days.
A few days later:
You will notice that your endurance increases and that you can run faster for longer periods.
Our cells use ATP as the main fuel source, ATP can be generated from different reactions, either anaerobic reactions(without Oxygen) for shorter periods of action or aerobic reactions for a longer period of actions eg: a marathon.
Aerobic synthesis of ATP requires a specific part of the cell called Mitochondria inherited from only your mother through a mitochondrial DNA.
When you exercise regularly, your aerobic metabolism increases and triggers Mitochondria biogenesis.More mitochondria=more energy=more endurance! Mitochondrial biogenesis depends on different factors including age, caloric restriction and of course exercise. It has been shown that the oxidative stress leads to a decrease in the functions of mitochondria.we know that any living cell uses oxygen to produce ATPs in the mitochondrial wall, with this consistent use reactive oxygen molecules are released. They are oxygen molecules with two additional electrons O2-.
They are able to react with almost any part of the cell, from the membrane to the DNA itself and cause some serious damage, luckily for us, molecules such as antioxidants react with these free radicals and neutralize them.
On one hand, caloric restriction alongside with increased glucose utilization reduce this oxidative stress, so that your mitochondria preserve its function and on the other hand exercise triggers the gene responsible for mitochondrial biogenesis PGC-1 by increasing the levels of a protein called AMPK (short for AMP-activated protein kinase).(Ref 5)
A few weeks later:
Clearly, you are in a better shape now and you can feel it ! you take a look in the mirror and you see a sexy body but what really happened?
The process of successive microlesions and regeneration finally start to pay off, your muscle fibers have grown in number and size shaping your muscles.
Also, you will be able to activate more motor units.A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron’s axonal terminals.
If the fact that’s why some skinny people are able to generate more power than bigger people, simply because they activate more motor neurons, thus more power.Training is, after all, a neurological process, it increases the number and the control over motor neurons.
That’s not it! , remember VO2? it starts increasing gradually that you become able to use oxygen more efficiently, you will able to run faster, longer and better.
Beyond one year of regular exercise:
Now you are more disciplined than 90 of people to be proud of that first. Your blood vessels are made of a certain set of cells called endothelium, with regular exercise your endothelial cells start producing more and more nitric oxide NO which has a vasodilative effect. As more and more accumulates, your blood flow is now better and the antioxidant activity of the endothelial walls is increased, this protects you from future atherosclerosis.
”Atherosclerosis is a disease in which plaque builds up inside your arteries”. (Ref 6)
You start producing more collagen and elastin which are types of fibers found in all connective tissues of the body. Your vessels increase in size and flexibility so you are less likely to suffer from hypertension and other cardiovascular diseases especially Strokes and heart attacks.
Moving on, your bones are now denser, thicker and you are fairly protected against osteoporosis, a disease that affects elderly due to decreased osteocytes or bone cells, alongside with other common diseases such as type 2 diabetes and joint pain. Scientists established a relationship between muscle mass and bone density, they found that more muscle solicitations anatomical response in the bones and the process of bone growth kick off.
This indicates that athletes are less likely to suffer from osteoporosis in the future or have fractures, but of course first, you need the proper nutrition for bone growth.(Ref 7)
Serotonin and dopamine levels in the brain normalize, so you feel joy and satisfaction. You are also able to tolerate more pain and life problems because your endorphin levels have increased dramatically. A workout is now your escape from any kind of stress. You literally become addicted to workout!
Now you are healthier and happier. You will definitely save a lot of money on medical care in the future,there is even a study that demonstrated that regular exercise makes you smarter by decreasing cortisol levels, the main stress hormone which can be responsible for early neurons degeneration and rising Irisin and BDNF levels which are two hormones responsible for neuron growth (Ref 8). Workout protects you from neurological degenerative diseases such as Alzheimer.
I found out after years of experience that telling is very different from explaining, when people understand how things work and why workout is wonderful for their health, they become more determined. This post is dedicated to any lazy person to raise his awareness.
References & Sources:
http://www.businessinsider.com/benefits-of-regular-exercise-2018-1?IR=T (Original inspiring article)