Human blood boils at approximately the same temperature as distilled water, 212 degrees Fahrenheit. This assumes that the liquid, either blood or water, is at 1 atmosphere of pressure. Any decrease in barometric pressure lowers a fluid's boiling point.
Human blood is a solution, but it is not very hypertonic when compared to distilled water. The tonicity of human blood is comparable to a 0.9 percent saline solution. An intravenous solution of 0.9 percent saline is often called normal saline because it has the same tonicity as the human body. This less than 1 percent increase in tonicity has a negligible impact on a fluid's boiling point.
