How to explain increasing resting heart rate?

[peyvalentine]

So I have started wearing my fitbit daily again as of the beginning of March, when my resting heart rate was recorded as being 70bpm. I have since started eating a lot more healthily, and exercising more regularly (3-4 times a week, mostly weight training with ample rest between sessions) and since then my resting heart rate has increased to 80bpm? I'm getting anywhere between 5-8 hours of sleep a night and haven't felt particularly stressed as of late, so I feel like my cortisol levels should be pretty under control.

Does anyone know why this might be occurring and what I might need to change? Is this something I should talk about with my doctor? Thanks in advance. 

[alexthecat]

Are you doing any cardio at all? I haven't found weight training to have much impact on my resting heart rate. I get much more benefit from doing fairly high intensity cardio on a consistent basis. My resting heart rate is 55 beats per minute, so that does seem to be working for me. 

[shipo]

@peyvalentine, I agree with @alexthecat, the workouts you're doing will have very little impact on resting heart rate, in fact, the opposite may well be true.  Why?  Because when you're engaged in weight training, you really aren't moving all that vigorously which may make your Fitbit think you're still "resting", even though your heart rate will be elevated, hence the increased RHR reading.

Then there is the cardio thing, because you typically have lots of movement for pretty much any type of cardio, your Fitbit knows you aren't resting, and tracks your heart rate differently during times of increased activity and increased heart rate.  FWIW, after four years of inactivity due to a series of injuries and health issues (pneumonia, broken bones, and then COVID), my resting heart rate gradually rose up into the high 50s; this last December I was finally able to start running again and sure enough, my RHR reading has dropped down into the low to mid 40s.

[robworkingout]

I see spikes in my resting HR if iv been eating too much even healthy food i still see increases. Also drinks high in sugar,caffeine can increase HR. Daily stresses can impact resting heart rate too. Also a rising heart rate could indicate the immune system is attacking a virus. We only become ill if a virus get out of control. Most virus our killed off before they start making us ill. If you think a talk with your doctor would help then i would recommend you do that this will help ease your stress levels. 

[peyvalentine]

I do 15 minutes of cardio on days with weights and 45 minutes one day of the week on its own, but no HIIT as of yet! I'm not so much exercising to decrease my resting heart rate, but thought it was worth mentioning because I've had a few people suggest the rise could be due to overtraining which I'm 100% sure I'm not doing

[peyvalentine]

I thought mentioning the weights might be helpful because I've had a few people suggest the rise could be due to overtraining, which I'm 100% sure I'm not doing 😓 I might cut back regardless and focus on cardio for a while to see if that changes things at all though, thank you!! Also, I'm so glad that you've bounced back from your illness and injuries, hope all continues to be well 😊

[peyvalentine]

Thank you for this! I didn't know the body responded to viruses like that, so that's definitely interesting! For peace of mind I think the doctor is still a good call, but knowing that there are so many different, reasonable explanations I hadn't even thought of has helped a little 😊

[Gentian]

You say, " I'm getting anywhere between 5-8 hours of sleep a night". Can you observe any link between your hours of sleep and your resting HR? Personally, I find I need anything from 7 to 9 hours in bed at night. 6 hours is not enough for me, and 6 hours one night usually leads on to 10 the next!. For most people, under 6 hours is considered inadequate. 

[Heybales]

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@peyvalentine wrote:

I thought mentioning the weights might be helpful because I've had a few people suggest the rise could be due to overtraining, which I'm 100% sure I'm not doing 😓 I might cut back regardless and focus on cardio for a while to see if that changes things at all though, thank you!! Also, I'm so glad that you've bounced back from your illness and injuries, hope all continues to be well 😊

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don't switch merely for improving HR readings - if making progress on the bar, you aren't overtrained.

If you just want some cardio training for hear, sure include some, but you already are. HIIT not required unless your cardio training will benefit from it.

Also - Fitbit's reading of resting HR is NOT the traditional 1st thing in morning reading before getting up for day - as commented it's all day type average - many ways to throw it off.

Have YOU taken your restingHR in the morning? Didn't see that stated in any comments.