Cardiovascular fitness is frequently considered the most important aspect of physical fitness because those who possess it are likely to have a lessened risk of coronary heart disease – the number one killer in our society. Cardiovascular fitness is also referred to as cardiovascular endurance, cardio-respiratory capacity and circulatory fitness. Regardless of the word used to describe it, cardiovascular fitness is complex because it requires fitness of several body systems.
Physical activity that leads to improved cardiovascular fitness has dramatic health and wellness benefits that extend well beyond heart disease risk reduction. It is important to the effective performance of virtually all types work and play activities.
Aerobic Exercise – Exercise for which the body is able to supply adequate oxygen to sustain performance for long periods of time
Anaerobic Exercise – Exercise that requires the use of the body’s high energy fuel. This type of exercise is of short duration and does not depend on the body’s ability to supply oxygen.
Hemoglobin – Oxygen carrying pigment of the red blood cells.
Maximal Oxygen Uptake (VO2 Max) – a laboratory measure of fitness commonly held to the best measure of cardiovascular fitness.
GOOD CARDIOVASCULAR FITNESS REQUIRES A FIT HEART
The heart is a muscle: to become stronger, it must be exercised like any other muscle in the body. If the heart is exercised regularly, its strength increases; if not, it becomes weaker. Contrary to belief that strenuous work harms the heart, research has found no evidence that regular, progressive exercise is bad for the normal heart. In fact, the heart muscle will increase in size and power when called upon to extend itself. The increase in size and power allows the heart to pump a greater volume of blood with fewer strokes per minute.
GOOD CARDIOVASCULAR FITNESS REQUIRES A FIT VASCULAR SYSTEM
Blood flows through a sequence of arteries to capillaries and to veins and back to the heart. Healthy arteries are elastic, free of obstruction and expand to permit the flow of blood. Muscle layers line the arteries and on impulse from nerve fibers control the size of the arterial opening. Unfit arteries may have a reduced internal diameter (atherosclerosis) because of deposits on the interior of their walls, or they may have hardened, non elastic walls (arteriosclerosis).
Fit coronary arteries are especially important to good health. The blood on the four chambers of the heart does not directly nourish the heart, rather, numerous small arteries within the heart muscle provide for coronary circulation. Poor coronary circulation precipitated by unhealthy arteries can be the cause of a heart attack.
GOOD CARDIOVASCULAR FITNESS REQUIRES A FIT RESPIRATORY SYSTEM, FIT BLOOD, AND FIT MUSCLES CAPABLE OF USING OXYGEN
In order for a healthy heart to transport oxygen through a healthy artery the blood must also be healthy. It must contain adequate hemoglobin in the red blood cells. Insufficient oxygen carrying capacity of blood is called anemia.
As fit blood travels through the lungs, adequate oxygen must be transmitted from the lungs to the blood.
A limited respiratory system will limit cardiovascular fitness. Delivering oxygen to the tissues from blood is called internal respiration. Internal respiration requires an adequate number of healthy capillaries. In addition to delivering oxygen to the tissues, these systems remove carbon dioxide.
Once the oxygen is delivered, these muscle tissues must be able to use oxygen to sustain physical performance. Physical activity that promotes cardiovascular fitness stimulates changes in muscle fibers that make them more effective in using oxygen.
FACTS ABOUT CARDIOVASCULAR FITNESS AND HEALTH BENEFITS
1. Good cardiovascular fitness reduces the risk of heart disease, other hypo-kinetic conditions and early death.
2. Low cardiovascular fitness...