Is pulse the most direct measurement of metabolism?
-
Is it even better than body temperature? Newborn babies have a bpm of up to 200, gradually declining until they reach the adult average of 60-100 bpm at 18. Body temperature stays mostly consistent throughout life as far as I know. That children have a higher metabolism than adults is well established.
Long distance athletes (i.e. people who trained their bodies to be in a perpetual state of stress) have a resting bpm as low as the 40s, while according to Ray Peat students who perform best on tests have a bpm of 85. That huge difference seems easier to make inferences from than the few degree differences in body temperature.
As a bonus, pulse is easier to measure than body temperature. No need for a thermometer, just use a 15 second timer on your phone while counting your pulse, then multiply by 4. Also, body temperature is influenced by the external environment to a degree that pulse rate is not. Ray Peat acknowledged this in an anecdote about taking the pulse rates of people during the summer while working in a clinic. They had hypothyroid symptoms and a pulse rate in the 40s while having high body temperatures.
Yesterday my bpm was 130+ in the morning. I was giddy, euphoric, randomly bursting into laughter while reading Wikipedia articles about British and German royal houses (not something particularly comedic). I ate some Bugles (made of starchy cornmeal) and I immediately felt sleepy. My pulse gradually decreased to 60 bpm in the evening and before I went to bed at night my normal depression had returned. This morning I had some sugar, my pulse went back above 100 bpm, my depression vanished and I started thinking more quickly. I didn't feel noticeably colder or warmer throughout this. All this makes me prefer pulse as a measurement to body temperature.
