Everyone knows that the heart is a muscle and many diseased hearts works on a pacemaker basis. Many do not know, however, that the heart is an extremely particular muscle as a whole and it works due to contraction of trillions of tiny cells called cardiomyocytes.
Researchers at the Cardiac Exercise Research Group, NTNU, have found out many benefits of both moderate and high intensity physical training on the heart cell functions even when animals have had myocardial infarction. Individual cells contracts better due to many structures rearrangements inside them! But how can this be linked to an improved heart function?
Curious and important characteristics of the heart:
- Initially, an electrical impulse (like turning the lights on) reaches a cell. Cells are connected to each other like electric cables, this makes the cells contract almost simultaneous from top of the heart to the bottom and then, like lights turns on in a room, the heart contracts in a synchronized way and pumps blood.
- While it has an electrical impulse, if supplied we enough oxygen, a heart beats even away from body, if there are ill cells in the way of the electrical impulse, it fails to propagate and this can lead to heart diseases due to arrhythmias or errors in contracting, just like a blinking lamp that suddenly turns off.
- Electrical properties and contracting of the isolated heart cells can be seen by special microscopes.
- Early in 1903, William Einthoven, as physiologist, (1860-1927) found out a way to measure this electric current in the heart, that was the electrocardiograph. This is the best way to measure and diagnose abnormal rhythms of the heart, particularly abnormal rhythms caused by damage to the conductive tissue that carries electrical signals.
- The heart needs to pump blood to the entire body, this means about 75 trillion cells, the only exception being the corneas. The heart works more than any other muscle through life; so it is important to have as many healthy cells.
- The amount of pumped blood from the heart varies from five to 30 liters per minute, a trained heart is stronger and work less to give the same amount of blood per minute. Squeeze a small rubber ball to try to imagine how the heart pumps blood to the body, the stronger one is, the more the balls will be squeezed.
Bearing this in mind, it is important to keep your heart healthy! The most important things you can do to prevent cardiovascular disease is to stop smoking, get enough physical activity, eat healthy and avoid obesity.
Written by Marcia Alves, Post doc at CERG.
Cardiac Exercise Research Group 