Rapamycin crushes my hrv, but then it recovers. It also decimates my Training Readiness.
What are the figures? When do you measure it,? Is it elite with polar or something else. When do you take rapa?
for me rapamycin increases parasympatic activity and increases hrv which elite sometimes interprets as more or less training readiness depending on my previous state
I’ve found something similar (especially when paired with meditation)…… Oura Ring is used to track changes
I have an Oura ring, and my HRV numbers are consistently horrible. (In the 20s, teens, and even single digits). Like, for a few years now. I exercise, am in great shape, etcetera, so I have no idea why.
I used to think my HRV meant I was going to just drop dead at some random point in the near future, but it hasn’t happened yet. 
I have both a Garmin Epix2 and an Oura ring. My HRV ranges from 35-25. I take Rapamycin 5mg once a week. I started around 2 months. I started slowly with 1 mg at night and my hrv plummeted with my first dose. It responded as if I’d just done a marathon. It recovered but I did find it interesting how quickly it declined. As I increased by 1mg a week to 5mg it never declined as much as the first time but every time I take it my hrv decreases for a few days. I have not had any side effects and I’m not surprised my hvr decreased. I would think taking rapamycin would be a stress on the body and hrv would decrease. I wonder how many people on this forum measure their hrv. I don’t think a decrease in hrv is necessarily bad. It’s just an observation.
I’m not sure of the significance of these changes in HRV, but it would certainly be helpful if we knew whether mice had the same impact from rapamycin (of course, probably too much to expect that the ITP is going to be measuring HRV on mice ;-).
But - there is an ongoing study in Macaques using rapamycin at UTexas and I need to contact them for some other stuff, so perhaps its something they might be able to track on them.
Do you mean " taking rapamycin would be a stress on the body and hrv would decrease"?
I measure my HRV in two ways. I use Elite (free software) combined with a Polar H10 strap. That IMO gives the best result I have an HRV when lying down in bed having woken for the day. This gives me a range between the mid 40s and mid 60s. Normally when I drink a lot of alcohol my HRV drops to about 48. However, when I am doing reasonably well my HRV is in the low 60s.
It is also measured when asleep by fitbit and then it ranges between the mid 20s and mid 30s.
I am 62. I don’t run very often. I do walk briskly, however.
*when I say best result I mean most reliable. It is also a higher value, but there tends to be a higher value when awake.