Bernoulli, hypertension, migraine

  1. I found the following thread on PF:
    https://www.physicsforums.com/showthread.php?t=207950
    that relates hypertension to Bernoulli's fluid pressure equations, and it got me to thinking:

    I am aware that sometimes migraine headache leads to temporarily elevated blood pressure. I have read various explanations for this (pain -> stress, etc.) - but could it be just plain Bernoulli?

    Since migraine is caused by (or causes?) dilation of blood vessels, wouldn't that lead to faster velocity for the same flow rate, thus lower pressure?

    Bernoulli also perhaps explains how exercise temporarily elevates blood pressure, i.e. by increasing the total energy ("head") in the system..?

    Any thoughts?

    --LG
     
  2. jcsd
  3. Bernoulli's principle works fine for large vessels and for very low viscosity fluids like air. But, it neglects viscous pressure losses. As a fluid mechanics guy, I can tell you that in flow through capillaries, such as blood capillaries, the pressure variations are dominated by viscous losses. This is the reason, for a given flow rate, the pressure drop per unit length is greater in a constricted region of the capillary than in an unconstricted region. In short, there is much more to fluid mechanics than the Bernoulli equation.
     
  4. SteamKing

    SteamKing 9,911
    Staff Emeritus
    Science Advisor
    Homework Helper

    People in extreme pain, like from a migraine, can also show elevated BP and heart rate. Exercise will raise BP because the heart rate is elevated to supply the muscles with increased oxygen.
     
  5. According to Bernoulli's principle, from all my nanoseconds of research, if a vessel was reduced, would presure subside a little?
     
  6. Migraine headaches are caused by neurogenic inflammation and vasodilation (increased diameter) of cerebral blood vessels. With stretching of the vessel walls, pain sensors are stimulated. Generalized symptoms of migraine result from pain related activation of the sympathetic nervous system. Medications used to treat migraines act to constrict cerebral blood vessels and reduce the stretching. This is precisely the opposite of what happens with most types of hypertension (high blood pressure) where systemic blood vessels may be constricted and are treated with medications which dilate blood vessels. Unlike migraines, hypertension is usually asymptomatic until there is end organ damage.

    http://www.ncbi.nlm.nih.gov/pubmed/11480266
     
  7. Thank you!
     
  8. russ_watters

    Staff: Mentor

    Welcome to PF. Did you read and understand my post in the thread?
     
  9. Also, the post #15 by Q_Goest in the thread is right on target, and elaborates on what I said in post #2 of this thread.
     
  10. DrDu

    DrDu 4,452
    Science Advisor

  11. I started a thread that may be interesting to some of you. It's not a researched hypothesis, or really a proper hypothesis at all, but rather a question to see if anyone else shares similar thoughts on the topic of hormones and coditions similar to the ones listed. https://www.physicsforums.com/showthread.php?t=722345
     
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