Exercise: A Look From The Inside
So we all know that exercise has several benefits. We know it helps us control our weight, boosts our mood and energy, prevents illness and diseases, and so on. But how many of us actually know what goes on inside of our body every time we workout? If we thought about our health from the inside versus the outer effects, we may be more inclined to get our butts out there and exercise! Here is a look at the effects inside the body from one single bout of exercise.
Let’s start with the basics. Our bodies are constantly regulating themselves. This is called homeostasis. The systems of our bodies work together to keep our temperature, blood pressure, heart rate, and etc. balanced. When we exercise, whether it lifting weights or running an ultramarathon, we challenge our body’s homeostasis which forces it to adapt and build strength and endurance. Here are the challenges made by exercise to each system in our bodies:
When a workload is placed on the body, the heart must pump faster to deliver blood which contains nutrients and oxygen to our muscles. The amount of blood our heart pumps with each beat, known as the stroke volume, must increase too. The blood pressure, which is the force of blood pushing against the walls of the arteries, is maintained by many blood vessels in our bodies constricting while those that supply our muscles expanding.
Interesting fact – research has shown that one single bout of aerobic exercise can reduce the risk of a major cardiovascular event, such as a heart attack, in those with cardiovascular disease. It was found that arterial stiffness and systolic blood pressure were reduced following sub-maximal aerobic exercise (1). If anything, we should exercise for the sake of our hearts!
The cardiovascular system delivers oxygen to your muscles, but the respiratory system is responsible for exchanging of gas with the outside environment. At the beginning of an aerobic workout, the depth of your breathing increases until it reaches a plateau. Further increases in ventilation come from breathing faster. When exercise is very intense, such as interval training, lactic acid produced by our muscles builds up in our tissues. As our bodies buffer lactic acid, it produces excess carbon dioxide, stimulating a further rise in our breathing rates to expel the CO2.
Some of us may find that we continue to breathe heavily after our workouts have been completed. That is because our bodies continue to need greater amounts of oxygen to break down the lactic acid build up in the muscles and restore any oxygen deficit acquired during exercise. Exercise affects lung function in the period immediately following exercise.
Our nervous systems orchestrate our body’s response to exercise. The autonomic nervous system is responsible for unconscious processes in our bodies. The sympathetic division, also known as the “fight of flight” system, prepares the body for action, while the parasympathetic division is active when you’re in “rest and digest” mode. During exercise, parasympathetic activity declines while the sympathetic division goes into overdrive, stimulating your heart and breathing rate and reducing blood flow to your digestive organs.
Our endocrine systems also helps to coordinate our body’s response to working out. Our adrenal gland secrete stress hormones which include epinephrine (or adrenaline), and cortisol. Epinephrine stimulates our heart to beat more forcefully and our sweat gland start to perspire. Epinephrine also prompts our fat cells to release fatty acids, while cortisol stimulates our liver to produce more glucose, or blood sugar, providing fuel to our muscles.
Now we know exercise is MUCH more than just looking good and feeling good. There is a lot that goes on inside of our bodies. These are the effects from just one single little workout. Imagine what the effects of lifetime of exercise would be like! If we start thinking about what is actually going on inside of our bodies and the gains that are being made towards our health, we may be less likely to skip our next workout. And hey, looking good and feeling good isn’t so bad either!