Does hot blood flow faster?


When we warm up for exercise we raise out body temperature to do thinks like thin the synovial fluid for range or motion

But the blood gets hotter - so you'd think it flows faster?
But if we sweat and do not dehydrate the blood get more viscous i presume and flows slower making exercise harder

Is this correct?
What other benefits does hot blood have on exercise (no innuendos please )

Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Guy Hengel [angelIII / a3]Billing EngineerCommented:
if it flows faster, it's not because it's hotter, but because the heart is feating faster...
it may also flow easier because the blood tubes get a bit larger (due to the temperature increase), but compared to the heard beat increase this has much lower impact

but having the blood running faster there will be faster (and hence more) transportation of oxygen and other nutritional "stuff" to the organs that need it, and faster off-loading of the "crap" generated that has to get off (CO2 etc)

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
First, the blood doesn't get hot. Second your ideas about its viscosity is also incorrect. It's better to leave medical theories to trained researchers; as such speculations, if believed and acted upon, are dangerous.

Thanks and Regards.
Your body will try to regulate blood temperature within a limited range.
Within that range, the effect of temperature on viscosity should be small.
Outside of that range, your body may have more pressing concerns than viscosity.

Sweating is one of the ways that your body may use to regulate temperature.
But excess dehydration can increase blood viscosity, which can be one of the dangers of excess dehydration.

Your heart will try to maintain blood flow required to supply to meet the oxygen requirements of tissues,
which tends to increase with exercise.
Blood viscosity can have an effect on the effort required to maintain this flow, but blood vessel dilation would usually be a greater factor.
Blood vessel dilation would allow greater flow at lower velocities which eases the effort required to maintain desired flow.
Learn Ruby Fundamentals

This course will introduce you to Ruby, as well as teach you about classes, methods, variables, data structures, loops, enumerable methods, and finishing touches.

The viscosity of blood is definitely meaningful (see, e.g., Blood Viscosity (Hemorheology) and others) , though it should only be minimally related to general exercise and common dehydration in a reasonably healthy person.

And blood being "hot" should only be considered as a relative description. Blood temperature will vary as thermoregulation takes place, and it will correlate with core temperature. In that sense, it does get "hot".

One mitigating factor will be dilation of blood vessels at large areas of skin that act as heat sinks. As the vessels widen, flow rate should increase. I'd expect that to be one of the largest factors, one that would more than offset any effect from normal dehydration through exercise.

Indeed, long term effects of exercise on blood viscosity may be more interesting than short term effects.

But if the original question is "Does hot blood flow faster?" I would say that the body's efforts to regulate excess temperature would generally tend to increase blood flow (assuming that "faster" refers to flow rather than velocity)
Agreed. Terminology might be tricky, so velocity can be inappropriate. Increased heart rate with decreased resistance (i.e., dilation) could seem to contribute to velocity, and it seems reasonable that elevated circulation rate would be an objective for regulation. But it might not actually translate to 'velocity'.

Many medical researchers (experts?) on Experts Exchange.  ;-)

Is there enough interest to open a new topic of "medical advice"?  Sorely needed by all.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Math / Science

From novice to tech pro — start learning today.