How does physical fitness affect the body's anatomy and physiology?
Physical fitness is defined as a state of well-being,health and the ability to do tasks without undue fatigue. Physical fitness can be achieved through good nutrition plan, moderate physical exercise and rest.
NOTE: there are picture wich some readers might find disturbing
Lets look at the picture below so we can see the difference between a physical fit person and a unfit person and determine how does it affect on our body.
Lest assume the person with 120 lbs is physically fit and the person with 250 lbs is a physically unfit person.
In this answer the focus is on unfitness and its damage to the body because physical fitness does the opposite to a particular system
#1 our heart and lungs
A person with 120 lbs is able to do longer tasks with more energy than a person with 250 lbs. This is because the person with 120 lbs has a better cardiorespiratory endurance. This is a measure which shows the ability of the circulatory and respiratory system to deliver oxygen and nutrients to cells and eliminate waste products from cells.
During physical activity our cells are "hungry" and they need oxygen and nutrients in order to fuel our muscles and they produce wastes that need to be eliminated. Cardiorespiratory endurance show us how efficent aou body is in doing this tasks.
To strenght our endurance we have to do aerobic exercises.
Atherosclerosis, the hardening of the artery walls, appears because of the high intensity of fat that accumulates inside your arteries.
Thicker walls allow a narrower space for blood to pass through and to maintain the same pressure the heart must work harder and blood circulation through the body suffers.
Picture 1. Obesity leads to development of osteoarthritis, sleep apnea...
Picture 2.The heart of the person with 250 lbs is two times heavier than the heart of the fitter person with 120 lbs. The heavier heart seems like a paper bag that is not able to pump blood.
Our lungs face risk in the presence of excess fat. Poor lung function results in lack of oxygenin blood vessels. The persin with 250 lbs has a bigger risk for obstructive sleep apnea than the person with 120 lbs.
#2 Our Colon
Colon cancer has a high connection with obesity. A diet high in processed meats and red meats increases the formation of colon polyps what can lead to colon cancer.
#3 Our Brain
Mental, social and emotional health is an important part of fitness. It seems reasonable to include the nerve sistem to this question.
In a 2010 study the white matter sheathing was more damaged in the brains of the obese.
#4 Our Skin
Obesity has an influence on hormone changes. Acanthosis nigricans, the skin appears darker and thicker. The person with 250 lbs on the top picture has a stretched skin what can cause redness and irritation. Poor vein function in ankles can lead to ulcers, because of lacking blood flow.
Our outer layer of the skin is our "protector" form infectious agents.
Stretched layer of skin can turn into illness, because the body’s mass in not compatible with the skin’s elasticity.
Physical fitness and unfitness has an impact on other systems like: muscle strength, muscle endurance, flexibility, body composition etc.
As you can see on the top on 250 lbs body the musles are a little bit squashed and the bones are "loaded" with "unnecessary burden".