How many cells can our blood tolerate?

June 14, 2012
Around 40 percent of the blood consists of red blood cells. They contain the red pigment hemoglobin and are responsible for the transport of oxygen. Credit: Jan-Peter Kasper/FSU

Bioinformaticians of Jena University (Germany) have found out that the optimal value of hematocrit -- which indicates the volume fraction of the red blood cells -- can be calculated with an equation that dates from no less a person than Albert Einstein. The red blood cells form the greatest part of bloods solid components -- all in all around 40 percent of the blood. The percentage of this component is not only similar in all human beings but also in many other vertebrates.

When people say "Blood is thicker than water," they are literally right. Because nearly half of the 'life liquid' consists of solid components. The form the greatest part of it – all in all around 40 percent of the blood. They contain the red pigment hemoglobin and are responsible for the transport of oxygen.

"It is amazing that the percentage of this component is not only similar in all human beings but also in many other vertebrates," Prof. Dr. Stefan Schuster of the Friedrich Schiller University Jena (Germany) says. Therefore it can be assumed that this value represents an optimum established by evolution. "If there was a lower volumetric content of blood cells, less oxygen would be transported," the chair of Bioinformatics of the Biological Pharmaceutical Faculty says. "If there was a higher content, the oxygen transport would be increased. But as the blood would then be more viscous, the speed of transport would go down at the same time."

As Prof. Schuster and his colleague Dr. Heiko Stark have just found out, the optimal value of hematocrit – which indicates the volume fraction of the red blood cells – can be calculated with an equation that dates from no less a person than Albert Einstein. The ingenious scientist engaged himself not only in the theory of relativity and quantum physics but also in the viscosity of liquids. "There are already a number of theoretical attempts for calculating the optimal hematocrit value in specialist literature," Schuster says. The Bioinformaticians of Jena University tried to find out which of those equations would be best suited to express the dependence of the viscosity on the liquid (blood) of the volume of the particles () and struck lucky with Einstein. The Jena scientists published their results in the latest edition of the science magazine Journal of Applied Physiology.

According to this the viscosity of a liquid is dependent on the viscosity of the solvent and the percentage volume of their solid components. Moreover Einstein's equation also has the factor 2.5. "If you apply a modification of this equation suggested by Arrhenius to the equation describing the speed of transport and establish the maximum, you obtain the optimum of exactly 40 percent," Dr. Stark says and calculates: 1 divided by 2.5 equals 0.4 or 40 percent. Therefore the normal hematocrit of human beings seems to be optimal from the point of view of fluid dynamics as well. This would also explain why the same value can be found in many animal species like for instance in lions, antelopes, goats, elephants and rabbits.

In their article the Bioinformaticists listed the experimentally calculated hematocrit values of a total of 57 species of from the literature. "However there are some aberrations from the optimum," Stark points out. The hematocrit of seals for instance is considerably higher with 63 percent. "Additional criteria might apply in this case." Marine mammals for instance need a bigger capacity to store oxygen as they dive for long periods of time.

With their results the Jena scientists also question the illegal practice of blood doping in sports: This means trying to raise the concentration of the oxygen transporting hemoglobin in the blood and thereby trying to increase the athlete's performance. This leads to an artificial increase of the hematocrit value. "This is not only a criminal offence, but at the same time its physiological effect is highly questionable according to our calculations", Prof. Schuster summarizes.

Explore further: Anemia may more than triple your risk of dying after a stroke

More information: H. Stark, S. Schuster, Comparison of various approaches to calculating the optimal hematocrit in vertebrates, J. Appl. Physiol. 2012, DOI: 10.1152/japplphysiol.00369.2012

Related Stories

Anemia may more than triple your risk of dying after a stroke

February 2, 2012
Being anemic could more than triple your risk of dying within a year after having a stroke, according to research presented at the American Stroke Association's International Stroke Conference 2012.

The doping-drug Epo has an impact in the brain

June 11, 2012
Sportsmen and women dope with the blood hormone Epo to enhance their performance. Researchers from the University of Zurich now discovered by animal testing that Epo has a performance-enhancing effect in the brain shortly ...

Recommended for you

The unexpected role of a well-known gene in creating blood

August 16, 2017
One of the first organ systems to form and function in the embryo is the cardiovascular system: in fact, this developmental process starts so early that scientists still have many unresolved questions on the origin of the ...

Researchers unlock clues to how cells move through the body

August 16, 2017
During its 120-day cycle the circulatory system transports red blood cells and nutrients throughout the human body. This system helps keep the body in balance and fight against infections and diseases by filtering old or ...

Eating habits affect skin's protection against sun

August 15, 2017
Sunbathers may want to avoid midnight snacks before catching some rays.

The lining of our intestines uses an approach known to business to quickly process food

August 15, 2017
Every time we swallow food, cells that line the intestines must step up their activity in a sudden and dramatic manner. According to a new study by Weizmann Institute of Science researchers, reported in Science, they rise ...

Therapeutic fusion protein could mitigate blood vessel damage from cardiovascular disease

August 15, 2017
Scientists from Boston Children's Hospital Vascular Biology Program have revealed an engineered fusion protein that could recover blood vessel health following the onset of hypertension, atherosclerosis, stroke, heart attack, ...

Chewing gum rapid test for inflammation

August 15, 2017
Dental implants occasionally entail complications. Six to 15 percent of patients develop an inflammatory response in the years after receiving a dental implant. This is caused by bacteria destroying the soft tissue and the ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

RobertKarlStonjek
not rated yet Jun 14, 2012
This equation should also consider air pressure eg residents at high altitude may well be different to that of low altitude.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.