Been reading this book on Heart rate training and I've started jogging again with purpose. It spells out specific heart ranges for specific adaptations and since I'm an utter novice, I can feel comfortable simply being a white-belt, that is, running to build my endurance. So I've been going on a couple of hour long jogs at a very easy pace.
I've had a lot of time reading and studying physiology and exercise and I guess I have for a long time known that your heart rate is elevated for hours after you finish a strenuous bout of exercise. But I don't think it ever occurred to me why that was. It was only in this book that it spelled out the obvious: the metabolic demands for recuperation following tissue breakdown brought on by strenuous work sends messages to your heart to increase its resting rate to facilitate the recovery. Thus your heart rate is an impartial and accurate measure of whether you have fully recovered from your previous stress.
I've been measuring my heart rates in the morning and without fail, my resting heart rate in the morning is around 70 beats. But measure it the day after a jog and it's up to 78. A day later, it's back down to 70. Like clockwork.
I can't believe I never knew this. How many times did I wonder whether I was going too hard or too soft? And my heart was telling me the whole time.
"My heart skips a beat"
I was dead tired after that first run and I was taking my pulse to get a sense of where my heart was at. I was lying down panting and the rhythm was...troublesome. It wasn't even. It would beat three times in sequence, then take a beat off, then repeat the three beats. I thought for a second that I was having an arrhythmia. I sat up and took it again. This time, it was five beats on, one off, five beats on. Then I stood. It was beating uninterruptedly.
I shook my head. Depending on whether I was standing, sitting or supine, the signals from my baro-receptors (blood pressure sensors) were changing the beat to compensate for the higher or lower blood pressure. Though the rate of beating seemed to be determined by my oxygen debt and fatigue, the rhythm was being altered to balance out the pressure that my system needed. So even though the frequency of beats stayed the same, an off-beat was inserted every 3 beats when lying down and every 5 beats when sitting to adjust my heart's output to my body's demand taking into account the effects of gravity.
I feel like I have this magical clock beating inside of me all this time and I didn't even realize it. Maybe I should see what it can really do!