Resting HR spikes (and sleep HR goes up) when sick

[angelafoodcake]

I've had my Fitbit HR since March now and I've been sick many times, and Very Consistenly I notice that my resting HR spikes up to "72" and stays there while I'm at the peak of sickness, and comes down when I'm well. Whatever formula they have seems to be extra magical in predicting the onset of viral illness because it starts to go up 2 days before I get any symptoms. Interestingly, the resting HR doesn't directly relate to overnight HR -- my overnight HR is "normally" 54-59, and when i'm sick and my resting HR is 72, my overnight HR is in the mid-to-high 60s. Most people's reactions to this is that the scale of change is insignificant (I'm a scientist / I get comments from other scientists), and I'd agree except that it's alarming precise and these noticeable spikes *only* happen when I'm sick. Anyone else noticing this magical prediction ability and mirroring of illness state??

[Perro]

My HR also went up two days before I got sick.  Got a sore throat and stuffy nose.  Went  from 70 to 96, will let you all know if it goes down when I’m over my sickness 

[Kglo]

My usually runs 59-65, but spiked to 70 when I was sick. Scared me until I saw these other posts!

[Vic1987]

I get exactly the same! Currently I'm fighting something off and my resting heart rate is up to 70 when it's usually about 62. Same with overnight heart rate, normally its 52 - 54 but currently it only drops as low as 64 in sleep because I'm I'll. Very interesting! How long does it take for your resting heart rate to get back to normal after your illness? 

[MarttaKelly]

Pretty much when you start to feel better. A week? Two weeks? Get well soon!

[Prospector]

I have noticed a similar effect with stress and anxiety recently due to lockdown. I’m more relaxed now, and my HR is getting back to normal - about 1bpm every day or two.

[angelafoodcake]

For me, it starts to go down on the day that my immune system starts
winning, and then goes down over the next week. E.g. when i had strep
throat, I could pinpoint the hour where my immune system started winning
and HR suddenly went down 30 points. So I use the RHR data, but also the
hourly/realtime data. For colds, it's less dramatic than for strep throat
or the flu, so you can't see the hourly / realtime change as easily, but
you start to see it go down in the RHR summary graph. I imagine with
COVID19, people wearing fitbits who are infected see a jump (would be
interesting for anyone with confirmed COVID19 to share their comments on
this thread).

[EricJon_H]

This is an interesting question, and work has been done, for instance

https://www.wired.com/story/wearable-covid-19-symptoms-research/ 

A Google search on fitbit/covid/rhr brings up other studies. 

[Vic1987]

Please let us know! Mine is still elevated and has been for over 2 weeks now! 

[Vic1987]

Thank you! Over 2 weeks and counting! I don't even feel particularly Ill.

[Vic1987]

Glad it's getting back to normal.

[Vic1987]

Thank you! 

[CrowLady]

Really interesting and I’ve read similar including a study using Fitbit data and flu/viral illness. I suffer from some kind of post-viral illness and find quite the opposite. My REsting Rate reduces massively when I am most ill and experiencing flu like symptoms. Like you I’m a scientist so not claiming significance on a single case study. There’s definitely signs of something going on though. 

[Prospector]

Interesting - I wonder what’s going on there. I guess the illness has somehow disrupted your normal metabolism.

Earlier this year I found an immensely strong correlation between stress level and increased resting heart rate. I also slept badly and lost some weight. As the stress reduced, I felt much better, but it still took a long while for my RHR to settle back to normal.

So the stress of being ill may be a contributor to elevated heart rate.

[minawoo]

Yes, I’ve been noticing this as well. My spikes with annual or semiannual viral infections (due to congested city with crowded commutes) are also 72, but last year, I also got hit by a bout of bacterial infection that spiked my RHR up to 84 until I took antibiotics. It took four months to get back down to mid 60s.