The circulatory system's role is to circulate blood to and from all parts of the body. This is a conveyor belt that circulates amino acids, minerals, vitamins, electrolytes, oxygen, carbon dioxide and hormones. Our circulatory system nourishes the body and helps fight disease, stabilises temperature, transports waste materials and maintains pH. The centre of this system is the heart.
Blood consists of plasma, red blood cells, white blood cells and platelets. An adult has around 5 litres of blood, and our kidneys filter 180 litres per day.
The human body evolved to move around and be active most of the day. A sedentary lifestyle, particularly sitting, hurts circulatory health. When you sit, blood flows slower and muscles burn less fatty acids which can dwell in the blood.