Free Breadsticks at Olive Garden

There's this joke about elite athlete heart rates...
Question: What does (insert Olympic athlete's name here) heartbeat sound like?
Answer: Boom. (pause 5 seconds)...Boom.

The joke being that it only takes one heartbeat every 5 seconds to circulate the blood instead of the regular-human, two-beat cycle every 2 seconds.

Let's talk about heart rate.
The basics:
Heart - the boom-boom thingy in your chest, protected by your ribcage. One of the strongest muscles in your body, besides the tongue and glutes.  It's got four chambers (atriums and ventricles), and an aorta, and blood is rushing through it all day, everyday...as long as you need oxygen, that is.

Electricity - energy, basically. The heart runs on it (yah, truth. Betcha didn't know you were running on electricity, eh?)  and there are other things in the heart's wiring like S-A and A-V nodes and a His-Purkinje system, but that's just boring Cook-Family dinner table banter.

Blood - that reddish fluid in your veins, made of plasma and cells, that travels around the body, cleaning out cells while delivering nutrients and O2.  Like your friendly sanitation team. Only, they drop off vitamins while collecting that week's worth of composting.

Respiration - breathe in. breathe out. Congratulations, you've just respired.  Now would also be an appropriate time to mention something medical professionals like to call the "cardiopulmonary cycle" - lungs and heart jam session, I call it.

Exercise - exerting yourself. See also: climbing stairs, swimming through rip currents, and yelling at the ref of every World Cup game.

Good, you have the basics.  Now let's give you a little overview of what happens to produce your heart beat...
You breathe in. Ahh, delicious fresh air. Lungs expand, oxygen is incoming and Boom that heart contracts and that incoming oxygen hits the blood flow currently going through your heart and Boom, say sayonara to that newly oxygenated blood being sent back into the body, while you breath out. Ahh, see ya later carbon dioxide.  Like a nicely functioning wait staff at your local Olive Garden: order up to the heart, blood delivers the free breadsticks, cleans off the muscles, and waits until you're ready for a free refill.  Every few seconds, boom-boom on autopilot - that's your heart rate.

Electrical charges help automatically regulate that heartbeat so that the blood keeps flowing and your breathing keeps going, but the heart rate may get adjusted, based on how much oxygen you need at any given time. For example, try holding your breath for as long as you can...
At some point, your body is gonna start screaming for a refill on O2 - and you're gonna be sucking in that air like you've never known relief.  You might find the heart rate speeds up a bit after you've gotten those huge gulps of air back into your lungs.  Herein lies the crux of exercising:

See, when you start exercising, more blood in your body gets directed to the muscles so that they can function better, making your breathing heavier as blood flow increases.  Imagine dinner rush at the Olive Garden.
Your Blood is just hanging out, happily attending to the tables, when, whammo!  Hyperspeed Delivery System alert...
Your Muscles start yelling, like, "Yo! I need some oxygen up in here!", like some hungry, disgruntled bachelor with no sense of table manners.
The Blood is like, "Oh yes, yes, right away!" and starts rushing around like the attentive front-of-house wait staff, ignoring the other Organs that are just awaiting their soup and salad refill, and sends a message to the Kitchen (heart and lungs) that they better get some bread sticks (oxygen, if you haven't figured that out) pronto for that Muscle over there in the corner.
And Kitchen gets all huffy, like, "Joe! More bread sticks for that table with legs!"
And Joe (your breathing) is like "Yah, ok! SPEEDING UP!"
And then there's those screaming Muscles, shoveling down the bread sticks as fast as they can, and throwing up crumbs all over the place, so Blood comes over and is like "Ugh god, they're making a MESS over here. Bob! Cleanup on Aisle 3!"
And Bob (Hemoglobin, Blood's back-of-house busser) rushes in, and takes all the gunk off the table and back to the Kitchen....
And those Muscles are just gonna keep refilling on the free bread sticks until the Kitchen can't make anymore...
And so it goes until dinner rush is over and Blood can resume normal service.

You've got to consider that doing dinner service like that, all the time, or at least for 30 minutes, 3 times a week, makes the staff more efficient - which is true.  Your whole cardiopulmonary system will learn to functioning more efficiently during the high stress time, and your muscles will be more polite about putting up such a fuss.  Technically speaking, all that stress makes your left ventricle adapt to hold more blood, and pump out a higher volume with each beat.  So, the more you speed up that heart rate and work those muscles out, the more O2-bread sticks your Blood can crank out of the Kitchen with any one order.
Hence, you get a lower resting heart rate at the end of the day.
(Which makes those Olympic-athlete cardiovascular systems seem like mild-mannered, Early-Bird-Special diners.)

This leads me to my main realization concerning last week's runs: my body is learning to be more efficient, but until the staff learns to operate calmly, I'm gonna be huffing and puffing for a while.  Part of the stress comes from the anxiety of knowing that I'm not getting enough O2 into my system fast enough, which causes enough panic to make anyone abandon ship and start walking.  The other dread comes from understanding that this metabolic-cardiopulmonary/vascular system doesn't take kindly to change, and so every time I start to exercise, there will be an elevated heart rate.  The revelation is that I've been working at 80-90% of my max HR during most every run, trying to maintain a race pace, or endure for more than 5 miles consistently, when I might benefit faster by training my body at 60-70% exertion, so I don't burnout my resources before happy hour.

It's like that saying: If it doesn't kill you, it makes you stronger.
Or that other saying: If you can't stand the heat, get out of the kitchen.

Or that one I like to say: It takes immortal strength to refuse Olive Garden bread sticks.