Why Zebras Don’t Get Ulcers Part 2: Stress Hormones and Cardiovascular Diseases

In the last part I covered how energies are redirected during stress to cause long-term implications in the body. But who directs these energies? You guessed it, various parts of the brain & body, through their messengers called neurotransmitters (acting locally) and hormones (acting towards distant organs mostly through transport by the blood). Here’s part 1 before you read on. 

Before I begin this, again I put a disclaimer and an apology if I get some of the technicalities not quite right. I’m just a biology, neuroscience, psychology enthusiast, not much technical training here.

Again going back to childhood biology, we all learnt of the sympathetic and parasympathetic nervous systems, parts of brain activating the stress response and relaxing us after respectively. (Taking a pause here to appreciate my biology teachers, so far, never had a bad one. Thank you for helping me remember all this.)

[start of technical jargon] When faced by a stressor, the sympathetic nervous system (let’s just say SNS for convenience) releases adrenaline/epinephrine and noradrenaline/norepinephrine. Adrenaline/epinephrine is released when SNS nerve endings act on our adrenal glands, noradrenaline/norepinephrine is released by SNS nerve-endings throughout the rest of our body. [Your SNS also diverts blood flow to your muscles (to fight or flee the stressor) and your PNS does the opposite.] Another important class of hormones in the response to stress are called glucocorticoids. Glucocorticoids are steroid hormones, also released in the adrenal gland through the signal of the hypothalamus-pituitary (parts of the brain). [end of technical jargon]

Epinephrine/adrenaline acts within seconds, glucocorticoids back this activity up over the course of minutes or hours.

If I were you, this is where I’d start raising alarm. I’m so glad my body is ready to support me if I’m in actual physical danger. But if I’m only in psychological danger/stress and that too daily, would I really wants minutes of that stressor (like an altercation with a colleague/boss) to keep hurting my body chemistry for hours? And what if that stressor is repeated many times a day, 6 days a week? I can actually leave this article right here; you’ve probably understood that the implication of this will be that glucocorticoids will be in your blood for hours after each such stressor. What does that mean? That means that your stress-response is activated for hours & hours daily. So yea, that’s that. But let’s see what more the book has to say. 

The author then goes on to tell us that ‘sympathetic arousal is a relative marker of anxiety and vigilance, while heavy secretion of glucocorticoids is more a marker of depression. 

Your SNS & glucocorticoids increase the rate at and force with which your heart beats. Rate is increased by the action of glucocorticoids, epinephrine and norepinephrine on your heart muscles; force is increased by your SNS (through epinephrine & norepinephrine) by constricting the veins supplying blood to the heart. The incoming blood pushes into the heart, the heart pushes back; force is increased. Thus, your heart rate and blood pressure have gone up. Please remember why your SNS & glucocorticoids are doing this, the blood flow rate is increased to provide more blood & energy to some muscles to fight or flee the danger. But hey, can you really fight or run away from that boss, guess not? So sit on your desk with increased heart rate and BP.

[Also note, the body is smart, blood flow may be increased to some muscles, but is decreased from other ‘non-essential’ parts, you know, basic physics law also learnt in school, conservation of energy; if more energy is supplied to the muscles, it’s probably taken away from other parts of the body. Also refer to part 1 to know which parts.]

So the heart beats at an optimal rhythm in regular conditions, and you guessed it, all that forceful tedious activity if prolonged can’t be good for your heart. All this can cause tissue damage in the heart and blood vessels and cause blocked arteries, heart attack, disturbed heart rhythm, even brain stroke (through the blood vessels reaching the brain). In case you need even more detail on how all this is actually occurring at a more micro level, go ahead and read the book. 

Let me present a few more fun facts that the author shares. If you do have thickened arteries, the increased heart rate and blood flow requirement through those arteries with less space for blood to flow, during your orgasm, can also put your heart under more stress and hurt your heart. What can a lay-person like me interpret from this? Once my stress has given me bad blood vessels, I should probably cut down on the orgasms, because those are now hurting my heart further. 

Also interesting study that Dr Sapolsky quotes is where animals chronically stuck in subordinate positions have twice the thickened-walled and narrow arteries as dominant ones, even on a low-fat diet. Also quotes a study in which working women with kids back home may be more susceptible to cardiovascular disease (guess leaving Guddu with papa/nani/dadi/nanny doesn’t really help). Also, women with unsupportive bosses seemed to be at higher risk as well. Totally surprised by this, are we? (It’s Sarcasm, clarification for the Sheldon Cooper-types.)

Anyway, I must end this article here with a small tip from the author, that unfortunately I fail to practice, but you should. Meditation with extended exhalations. When you inhale, you turn on the SNS slightly, minutely speeding up your heart. When you exhale, the PNS turns on, activating your vagus nerve to slow things down. I remember this Art-of-Living workshop back in my MBA college that taught us this. They didn’t give us the science behind practising it. Now I know the science behind it and still don’t practise it. But you can. You may or may not take this unsolicited advice. 

The author correlates stress and many other ailments. Guess I’ll write about those soon as well. You know, the usual, stomach problems, reproductive problems, immunity, memory, mental health issues, drug abuse. He’s kind enough to help us manage stress as well, so I will also share the same with myself? I guess when I write, the only constant reader is me…

But you should read the book in case you don’t have the patience to wait for my articles (if at all you are interested).