Almost one and a half times the size of a fist and weighing between 300 and 350 grams, it beats more than 100 000 times a day. It pumps 4.5 to 5 litres a minute when beating 60 to 80 times at rest. In total it can beat more than two billion times during a lifetime. This impressive machine, our heart, is a hollow muscle that allows us to live.
A sturdy yet fragile muscle, the heart must be cared for closely. Find out about its mechanisms to better understand how to look after it.
Located between the lungs, in the middle of the thorax, the heart is the motor of the cardiovascular system, the pump for the circulatory system. Its role is to pump blood which is then sent to the tissues of our bodies, allowing them to function. To pump all of this blood, the heart needs oxygen and nutrients which are supplied by the coronary arteries.
The heart is made up of four cavities:
- two upper cavities, the auricles,
- two lower cavities, the ventricles.
These cavities have the role of pumping almost 8000 litres of blood per day with the help of around 60 to 80 heart beats per minute at rest. At the top of the right auricle is a small piece of heart tissue called the sino-atrial node. This is what controls the beating mechanism. In fact, it is what tells the heart to accelerate its beats during exercise or to slow them down when we are resting.
Each half of the heart is independent of the other. The right side receives "dirty" blood, lacking in oxygen, that has been used by the body and sends it to the lungs for them to remove the carbon dioxide and re oxygenate the blood. The pulmonary artery, which sends the "dirty" blood to the lungs, is the only artery in the human body to transport blood low in oxygen. The left side receives "clean", re oxygenated blood and distributes it around the body.
When the heart contracts, the blood is pushed into the aorta, which is the biggest blood vessel in the body, and is distributed throughout the body through a network of arteries. The left ventricle is in fact much bigger than the right because it needs to have enough strength to pump blood around the whole body.
The heart has, on average, a diameter of 12 to 14 cm although it is slightly larger in men. An adult heart weighs between 300 and 350 grams. Its structure is the same in all mammals as well as birds, although the heart rate changes (for example, for a gray whale, it is 9 beats a minute!). In humans, the heart rate is higher in women than men and in children than adults.
Finally, large variations in the heart rate have a name: tachycardia when the pulse is fast, and bradycardia when it is slow. The heart's electrical activity can be recorded with an electrocardiogram.
The heart is a rather sturdy organ. But that doesn't mean that if you don't look after it, it won't become fragile and vulnerable. So here is some advice for limiting the risk of cardiovascular disease or heart attacks:
- eat healthily by controlling your consumption of fatty or very salty foods to maintain a stable weight (obesity considerably increases the risk of heart attacks). You should also avoid drinking alcohol to stop the appearance of "bad" cholesterol.
- Similarly, eat fruit and veg every day and regularly eat food rich in omega 3 such as oily fish, colza oil, nuts or even soya which protect from cardiovascular diseases.
- Avoid smoking to reduce the risk of suffering from these illnesses
- Don't ignore medical advice, and follow your doctor's recommendations. Watch out for the symptoms of heart disease.
- Reduce stress by finding a good outlet such as meditation. Stress is very bad for the heart.
- Do exercise (30 to 60 minutes a day is recommended) to tone up your heart and maintain a stable weight. And yes, the heart is a muscle so take care of it!
- Check your cholesterol levels every year to prevent the risk of illness and maintain a healthy level (below 100). However, you still need "good" cholesterol.
- Likewise, you should check your blood pressure and maintain it at a steady level.
If you would like more information about heart health, do not hesitate to consult your doctor.