HR down but BP up?

#1

Hi folks,
I was wondering if anyone had an answer to this.

My typical resting HR is between 55-57. When I water fast for 20+ hours, I notice that my HR can go between 49-51 while just sitting on a couch watching TV (according to my FitBit Charge 2).

When I measure my blood pressure I notice that my systolic goes up about 10 points and my diastolic can go up by 3-5 points.

I would have figured that my blood pressure would also go down since there’s less stress on my system from not having to digest anything. Is this typical?

(Joey) #2

There’s a fairly common condition known as “postprandial hypotension” … i.e., one’s blood pressure drops after eating.

Perhaps the experience you’ve noted illustrates the flipside of that same metabolic dynamic, which would be having blood pressure rise when not eating?

#3

Interesting. I didn’t know that was a thing.

Maybe my heart is overcompensating because it’s expecting me to digest something and there’s nothing there to digest. I dunno.

(Joey) #4

Not sure what your heart might be expecting :thinking: … but our systems tend to slow down when we’re digesting (we get tired, sluggish) as energy is directed toward that intensive process of metabolizing nutrients.

The lack of food to digest allows one’s metabolic energies to be directed elsewhere. It may just be that simple.

#5

I’ve also noticed that my resting HR goes up for a couple of days after ending a 36+ hour fast. I hit 60 bpm and am now on the way back down.

I take it that my body is doing good things with the new-found calories that I ingested causing the temporary increase in HR.

#6

Both of those are pretty ignore-able amounts, probably just a stress response of not eating for a day.

(Kirk Wolak) #7

Actually, I notice this generally.
Think of it this way. The higher the PRESSURE the fewer beats it takes to move the blood.
The lower the pressure, the more beats…

The lower beats could be less cortisol, or lowered metabolism.

But those are small numbers. I can see my change by 30+ / 30+
And I typically have a slightly elevated BP @ 60 BPM.