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Friday, March 1, 2013

Is this why running out a stress works?

Another tidbit from clas.

Way back, last year, I learned an interesting thing about stress and physiological response to stress. There may be a beneficial physiological consequence of a flight or flight stress response ending in actual flight or fight!!!!!

This is very relevant to our horses, since is seems like most of our interaction with them is about either not triggering that flight/fight response, or teaching the horse to NOT respond to a stressful situation in either flight or fight. Instead we ask them to chose a non-phyiscal ending (such as standing there) to the stressor, or (applying this concept to ourselves) perhaps we are dealing a stress that is triggering a flight/fight response in us, that we do not respond to in a physical way --> such as the stress of studying for an exam, and that stress culminating into taking the exam (which is NOT a physical conclusion).

I've noticed in both myself, my horses, and my dog that the best way to completely resolve stress, whether physical or mental, is to do something physical that causes me to get out of breath and my blood to start pumping. Farley is calmer after being allowed to explode (safely) after a stressful training session - perhaps in a good turnout session in the arena. Tess needs to go into zoomies around the property if I've pushed her in a shaping session. If I'm stressed I can try a lot of different techniques to try to forget and relax, but the most effective way to "reset" myself is something involving cardio.

It turns out there may be an actual physiological mechanism to this.

The flight and fight response causes activation of the sympathetic autonomic nervous system response. A quick refresher on the nervous system......the parasympathetic is the "rest and digest" control. Heart rate is relatively low, blood pressure low, blood flow is going to the gut to digest that big meal that was just eaten. Sympathetic is what kicks in when you see that bear. The eyes dilate, the heart rate increases, the peripheral blood vessels constrict which raises your blood pressure.

So......You've seen the metaphorical bear whether it's an actual carnivore, or something more insidious like an exam or a public speaking engagement. Your sympathetic system has been activated and you are poised to flight or flight.

Let's say you allow an actualy physical flight response and you are now pounding the pavement or urging your horse down the trail to escape the jaws of death.

The arterioles, tiny vessels containing oxygenated blood, usually moving towards a capillary bed, in the skeletal muscles dilate. Remember that initially these peripheral vessels constricted due to the sympathetic response! Why would they dilate? Exercising muscles accumulate byproducts/metabolites that (through a mechanism that I had to learn but I'm not going to make you learn......) cause a reflexive dilation of that vessel......

This "vasodilation" in the arterioles of the skeletal muscle, can actually reverse the effect of overall sympathetic vasoconstriction in other organs of the body.

Remember that the overall vasoconstriction due to the sympathetic response in the beginning of this scenerio means that you are pumping a constant amount of fluid (blood) through smaller "pipes" than usual so your blood pressure is up, blood is returning to the heart faster etc. Dilating the arterioles is going to cause the amount of blood returning to the heart to be less because the pipes just got bigger in one area.

This will cause your blood pressure to return toward normal despite the increase in cardiac output (cardiac output is the amount of blood your heart is pumping).

Thus, a flight or fight stimulous that ends in actual flight or flight/strenuous activity, actually causes the system to return to the non-stressed, normal state!!!!!!!!

What about situations that do not resolve in physical activity? Emotional stress often provoke a flight-or-fight response but don't always resolve in muscle exercise. Medical students taking an examination is an example. A stalled horse that doesn't like ballcaps who has ball-capped-clad humans passing in front of his stall all day. A horse in a small paddock that is being exposed to lots scary stimuli but can't respond by running. A horse at his first endurance ride tied to a trailer.

While my reading on the subject didn't give any definitive answers to this, it did state that "it seems likely that repeated elevations in blood pressure because of dissociation of the cardiovascular component of the flight-fight response from muscular exercise component are harmful".

Seems like an excellent hypothesis for why stress in humans can cause disease, why my horse seems calmer if allowed to run a bit after being good (ie not bolting) through a scary situation, and why a horse in a small paddock on a windy day is "high", even if they are technically getting enough exercise.

How do I use this information? I'll make sure that I'm resolving stress in my life through PHYSICAL release, and I'll make sure that I'm allowing my animals the opportunity to do so in a safe manner as well.


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