Very low resting heart rate

[Star8181]

I think I know this isn’t great but here goes. My resting heart rate is getting lower every month, it used to be average 58bpm but is now around 45bpm but often lower when I’m asleep. Last night my Fitbit tells me it dropped to 36bpm for a while.
Now I have an eating disorder and I know that restricting food can lower your heart rate but I’m only restricting to 1000 calories a day so not too bad. But it’s also coincided with me running a lot more, I run 2-3 miles every day so maybe it’s just because I’ve just got fitter? Which is it most likely to be - fitness or eating disorder? I’ll go to make a doctors appointment tomorrow.

I'd say fitness is probably the reason. My husband's RHR dropped into the 30s/40s when he started running.

Do you get any other symptoms? If you feel weak or dizzy with it, go to the doctors. If you feel perfectly healthy then don't worry.

Thanks, I often feel dizzy if I stand up quickly and sometimes almost black out and my heart rate spikes but it’s probably because I’m not eating enough. Doesn’t happen every time though, I go through phases of it.

It would be a good idea to see your doctor then.

I'd say running aswell. My partner used to play football semi professionally and his used to be 45bpm it's only started to go up slightly since he stopped playing over a year ago. He's been to the doctors about it as i was worrying and they agreed it's due to exercise.

Hopefully yours is the same but best to get it checked to be sure.

FATE - HR in the 30s is not normal. Even if you’re fit

Eating disorder will cause an imbalance of electrolytes and your heatbeat will be affected.
I fear this rather than you becoming fitter.

I'm not sure how accurate a Fitbit is - have you ever checked by feeling your pulse?

Doe your Fitbit show how your heart rate behaves during exercise - does it rise appropriately and then return?

My resting heart rate is usually between 45-50, but I am half marathon fit, and run considerably longer distances than you (but not usually every day - you need recovery days too)

I don't know how your eating pattern would interact with exercise and heart rate, so I think it is definitely worth asking your doctor. Especially when combined with dizziness. Are you ever short of breath?

@ChelseaCat it's not unusual in the running community.

A Fitbit isn't an accurate way to measure a pulse, speak to your doctor but take what your Fitbit says with a pinch of salt.

Thanks for the messages, I have occasionally woken up in the night feeling a bit odd and my heart rate is in its 30s (but I don’t sleep well anyway). I’ve checked my heart rate on an oximeter I have and it’s the same so think Fitbit is fairly accurate.
I don’t think I’m ever short of breath, as I said, I do feel ‘odd’ but again I don’t know whether I’m anxious. My heart rate does spike a bit though when I stand up, goes to around 80bpm, not sure if that’s normal or not. I must admit, the running is becoming harder. Back in April I could run 10k but I feel too weak now.

30 is slow a d you feel dizzy sometimes, you should see your doctor for an ecg and any other tests they think are appropriate.

You need to talk to your doctor about your eating disorder, your dizzy spells on standing, your food restricting, and the fact that you are trying to run more while feeling weaker and weaker.
You’re right. It isn’t great, and you know why. If ‘fitness’ was the issue here, you wouldn’t be feeling that the running was getting harder.

Thank you, my doctor knows about my eating disorder and I am on the waiting list for treatment. I am definitely going to get an appointment tomorrow, even if they can just put my mind at rest.