Chronic Stress and Cardiovascular Disease
if you sit and think about a major deadline looming next week, driving yourself into a hyperventilating panic, you still alter cardiovascular function to divert more blood flow to your limb muscles. Crazy. And, potentially, eventually damaging. (Location 738)
⇒ The Cardiovascular Stress-Response
The little blood vessels distributed throughout your body have the task of regulating blood flow to the local neighborhoods as a means of ensuring adequate local levels of oxygen and nutrients. If you chronically raise your blood pressure—chronically increase the force with which blood is coursing through those small vessels—those vessels have to work harder to regulate the blood flow. Think of the ease it takes to control a garden hose spritzing water versus a firehose with a hydrant’s worth of force gushing through it. The latter takes more muscle. And that’s precisely what happens at these small vessels. They build a thicker muscle layer around them, to better control the increased force of blood flow. But as a result of these thicker muscles, these vessels now have become more rigid, more resistant to the force of blood flow. Which tends to increase blood pressure. Which tends to further increase vascular resistance. Which tends… (Location 746)
Once this layer is damaged, you get an Inflammatory Response—cells of the Immune System that mediate inflammation aggregate at the injured site. Moreover, cells full of fatty nutrients, called Foam Cells, begin to form there, too. In addition, ==during Stress the Sympathetic Nervous System (SNS) makes your blood more viscous.== Specifically, Epinephrine makes circulating platelets (a type of blood cell that promotes clotting) more likely to clump together, and these clumped platelets can get gummed up in these aggregates as well. (Location 768)
==Stress can promote plaque formation== by increasing the odds of blood vessels being damaged and inflamed, and by increasing the likelihood that circulating crud (platelets, fat, cholesterol, and so on) sticks to those inflamed injury sites. (Location 774)
How can you measure the amount of inflammatory damage? A great marker is turning out to be something called C-reactive protein (CRP).
subordinate males show a lot of the physiological indices of chronically turning on their stress-responses. And often these animals wind up with atherosclerotic plaques—their arteries are all clogged up. (Location 797)
the animals precariously holding on to their places at the top of the shifting dominance hierarchy who do the most fighting and show the most behavioral and hormonal indices of stress. And, as it turns out, they have tons of atherosclerosis; some of the monkeys even have heart attacks (abrupt blockages of one or more of the coronary arteries). (Location 803)
But if you couple the social Stress with a high-fat diet, the effects synergize, and plaque formation goes through the roof. (Location 808)
Clog up a blood vessel in the brain and you have a brain infarct (Location 817)
Just when your heart needs more oxygen and Glucose delivered through these already clogged vessels, acute stress shuts them down even more, producing a shortage of nutrients for the heart, myocardial ischemia.(Location 829)
by definition, if you are turning on the sympathetic nervous system all the time, you’re chronically shutting off the parasympathetic. And this makes it harder to slow things down, even during those rare moments when you’re not feeling stressed about something. (Location 848)
Whenever you ==inhale, you turn on the Sympathetic Nervous System (SNS) slightly== , minutely speeding up your heart. And when you exhale, the parasympathetic half turns on, activating your vagus nerve in order to slow things down (this is why many forms of meditation are built around extended exhalations). (Location 853)
==Large amounts of variability (that is to say, short interbeat intervals during inhalation, long during exhalation) mean you have strong parasympathetic tone counteracting your sympathetic tone, a good thing.== (Location 857)
see also
Tags: neurobiology science
Superlink: 051 ☣Neurobiology 050 🧠Neuroscience
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3 Stroke Heart Attacks and Voodoo Death
Erstellt: 01-09-22 11:23