Blood is heavier than water, having specific gravity 1055, compared to that of distilled water which has the value 1000. Blood density depends on the proportion of its components and in particular of red blood cells and proteins.
Blood is more viscous than water. Relative value of blood viscosity is 4.5, compared with the viscosity of water considered 1. Blood viscosity is the property of blood to adhere to vessel walls and is based on the number, shape and size of red cells. Viscosity ensures laminar flow (in layers) of blood through the vessels, viscosity increasing over certain values aggravates circulation.
Blood viscosity and blood density are two different physical properties that are closly related and dedending on the properties of water. We are looking at the factor to change physical characteristics of a liquid mixture of biological and non-biological component.
1. Blood viscosity depends on the content of the blood, or the concentration of each of many components in the plasma fluid. It depends on the concentration of red blood cells and the proteins present in the plasma.
2. Blood density is a measure of weight per volume unit. Certainly it depends on the configuration of concentrations of many components in plasma. However, blood density can be changed by gesture because local blood pressure has an effect on blood's volume and density.
There is a broad range of factors affecting blood viscosity and viscosity. They can be anything from the food and drink one consumes, medications, health conditions, heart conditions, temperature and altitude, body activities, and mental wellness, ... etc. Keep in mind that species having blood are complex one and the blood inside is a complex mixture which is not under controlled conditions