If a coronary artery is partly blocked by a build-up of fatty material, it will begin to narrow.

This causes coronary heart disease and reduces the flow of blood through the artery to the heart, resulting in chest pain and shortness of breath.

The restricted blood flow to the heart also means that less oxygen will be transported by the coronary artery to the heart’s muscle cells.

This means less oxygen will be used by the heart muscle cells in respiration to provide energy for contraction.

Over time, this may weaken the heart muscle, meaning the heart cannot pump out enough of the blood it gets from the lungs. This negatively impacts the respiratory system, and leads to breathing problems.

Weakened heart muscle can also lead to heart failure, which means that blood cannot be properly transported around the body. This means that body cells and tissues do not receive enough oxygen and nutrients, such as glucose.

Finally, if the heart becomes starved of oxygen, this could result in a heart attack, which can be fatal.