September
Function:
The function of the heart is to deliver blood to the various systems and organs in the body. Blood carries both oxygen and nutrients, providing the body with nourishment and energy.
Mechanics:
The heart pumps blood by contracting, or squeezing, blood out of its chambers.
At rest, a normal heart rate is in the range of 60-80 beats per minute, but may vary widely from one person to another. It is not unusual for a well conditioned individual to have a heart rate of less than 60 beats per minute at rest.
Teh maximal heart rate someone can achieve is approximately (220 - their age). For example: If you are 10 years old, your maximal attainable heart rate would be 220 - 10, or 210 beats per minute. As people get older, they do not have the same heart rate capacity. Using the formula of 220 - age, calculate the maximal attainable heart rate for your parents or an older brother or sister.
Oxygen Transport:
When someone exercises, blood is redistributed from organs and non-working muscles to those muscles that need energy. Blood is carried away from the heart in the arteries and returns to the heart by flowing through the veins.
During exercise, blood pressure increases as blood becomes concentrated in those working muscles while the heart continues to beat faster and more strongly.
Thes changes are normal during exercise. Blood pressure and blood flow return to normal after the several minutes of cool down activity that follows exercise.
Volumes:
During exercise, the amount of blood pumped out of the heart (blood flow) increases, the strength with which the heart contracts increases, the rate at which the heart beats increases, and the body's ability to take oxygen from the blood to create energy increases.
A stronger, better-conditioned heart beats at a lower rate during easy exercise and has a greater capacity during all-out exercise.
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