# What is the speed of blood in when flows through the fingertip?

What is the average speed of blood as it flows through the index finger on the right hand?

• The answer is going to be highly dependent on the level of the vasculature you are talking: through the largest artery or capillaries you will get different results, and different results in veins as well, and it will depend on many other physiological parameters. You are asking a seemingly specific question but with almost no details, like if I asked "what is the average speed of a person?" Well, do you mean their average max running speed? Their day-averaged velocity including walking, sleeping, driving? Average of all people or just adults? As-is, your question is far too broad. Jan 18, 2017 at 1:13
• @BryanKrause I'm asking for use in a heart rate detection application which detects the heart rate based on the user's fingertip pressed against the camera. I'm not knowledgeable about veins and such.
– fi12
Jan 18, 2017 at 1:16
• @BryanKrause because of that, which of those blood vessels would directly impact what I'm doing?
– fi12
Jan 18, 2017 at 1:16
• Why do you think velocity is important for that? Jan 18, 2017 at 1:16
• @BryanKrause my algorithm is slightly different than other ones out there, because it attempts to find the user's blood speed as well. That's why I'm asking.
– fi12
Jan 18, 2017 at 1:17

This reference gives about 10-20cm/s in the major arteries and 5 cm/s in the major veins of the index finger in 5 male subjects, though there was a lot of variation.

The answer is going to be highly dependent on the level of the vasculature you are talking: through the largest artery or capillaries you will get different results, and different results in veins as well, and it will depend on many other physiological parameters.

Because it will vary greatly, even within individual vessels, you can't use the speed to estimate volume per time because the vasculature does not maintain a constant diameter; in fact, changes in vessel diameter are the major contributors to changes in flow volume.