Low heart rate related to diet?

If you are asleep, how do you know your HR dips below 40? That's just me being curious! I have always understood that young, athletic people often have lower heart rates, which is apparently very normal, but you didn't say what your "normal" resting heart rate is. You've said that you struggled with an eating disorder in the past, but have overcome that and your weight is now "normal," yet your doctor is telling you not to exercise as you aren't eating "enough!" Since your EKG was normal, we can rule out your past eating disorder having caused any cardiac issue. So, I'm probably as confused as you are......especially since you have no symptoms. You ask if your "issues" could still be due to "under-eating," and that gave me a bit of a pause. Do you mean under-eating in the past or are you STILL under-eating even though you say your weight is normal? I can't help but feel there is a piece missing from this puzzle. Since you have overcome your eating disorder, your weight is "normal," and your EKG was good...…(Not knowing your height, weight or build, I don't know if a BMI of 24 is good or not).I don't understand why your doctor says no exercise....but if it has something to do with an ABNORMALY low heart rate, it seems they should have referred you to a cardiologist. That your doctor just said "don't exercise" without suggesting other tests leaves me a bit uncomfortable. I would definitely get a second opinion and if your insurance covers it, I'd try to see a specialist in sport medicine....but if that is out of reach, a second opinion, in my humble and non-medical opinion, is called for. I wish you the best.

Hello @abbyd13, I'd like to add my welcome to @rubywitch67's. Ruby asked some good questions here. Was there any more explanation as to why you are not supposed to exercise? Were you referred to another physician or cardiologist to investigate the heart rate in more depth? Here is an interesting excerpt from Mayo Clinic's page on Bradycardia:

"Bradycardia is a slower than normal heart rate. The hearts of adults at rest usually beat between 60 and 100 times a minute. If you have bradycardia (brad-e-KAHR-dee-uh), your heart beats fewer than 60 times a minute. Bradycardia can be a serious problem if the heart doesn't pump enough oxygen-rich blood to the body. For some people, however, bradycardia doesn't cause symptoms or complications."

It goes on to say, "A resting heart rate slower than 60 beats a minute is normal for some people, particularly healthy young adults and trained athletes. For them, bradycardia isn't considered a health problem."
https://www.mayoclinic.org/diseases-conditions/bradycardia/symptoms-causes/syc-20355474
@abbyd13, in addition to Ruby's questions, did your provider mention the term bradycardia at all?

I don't know if it's very accurate but I sleep with my Applewatch which tracks your heart rate and I was getting "alerts" on it saying that my HR was going below 40 while I was sleeping (37,38,39). My resting HR is around 50 during the day (again according to my Applewatch). Referring to your question about the under-eating, my doctor believes that the low HR is a result of under-eating NOW. This is where I am confused and frustrated because my weight is healthy and I do not feel like I am under-eating. I have received help from dietitians in the past and I believe I have corrected any issues with my diet since my habits of disordered eating occurred. (I used to be quite underweight and have been in a healthy range for a couple of years now.) I guess the thing that bothers me most is that they are only looking at my HR and ignoring the fact that my EKG is normal. I think they are only blaming it on under-eating because of my history, but it just doesn't make sense at this point given some of the things I've mentioned.

Thanks for your response. I actually stumbled upon the term myself and have mentioned it to them, but they are convinced the only thing resulting in my low HR is my diet. I mentioned some more details in my response to @rubywitch67

Hi Abby......after rereading the posts between you, me and our learned moderator, Justin, I am more convinced than ever that you should seek a second opinion from a cardiologist. Justin asked, without a doubt, the most important question of all......a question I'm a bit dismayed I failed to ask......which is "What explanation did your doctor give you for his recommendation that you stop exercising?" Did you inform him of the readings you were getting from your Applewatch? It's POSSIBLE, since the Applewatch is most likely NOT considered a certified "medical device" like a Holter monitor or Zio patch, that he ignored the readings you were getting from it. I don't know that for sure....so that opinion needs to be taken with a grain of salt. But, it seems to me, at the end of your appointment, you were told....."my heart rate dips below 40 bpm at night when I'm asleep because I am not eating enough and my doctors will not let me exercise." As Justin asked, did this doctor not discuss bradycardia with you? I'm guessing he didn't since you state "you stumbled upon the term yourself and mentioned it to them." The more I think about your doctor, Abby, the angrier I get. As a retired RN with 4 heart surgeries under my belt, the last being less than a year ago when I underwent an ablation for AFIB, my advice remains (even stronger now) for you to RUN to a cardiologist (preferably not one associated with your doctor) and get the correct tests, answers, explanations, diagnosis and any treatment.....IF NEEDED, from a doctor who understand the heart a great deal better than your current doctor. (I am still amazed your doctor, who suspected bradycardia, did not immediately refer you to a cardiologist...….especially since he thought it medically imperative that you stop exercising!) This doctor is NOT practicing good medicine. I WAS going to send you to the Mayo Clinic site for bradycardia, but when Justin already did, I was very pleased. I hope you have checked out the site and have taken comfort in knowing that some of the top doctors in the world agree that there is NOTHING wrong with you. But I am STILL recommending you see a cardiologist since you CAN get reassurance from the Mayo Clinic, but they can't run tests over the internet. A few tests will do more than reassure you, they will PROVE your heart is healthy as a horse! Your EKGS will back this up, your past eating disorder will be proven moot, what will be determined is you are at a healthy weight and probably have a perfect BMI. I'm betting your "diagnosis" will be that we should ALL be as healthy and athletic as you. But there is no reassurance in the world better than your cardiologist saying "YOUR HEART IS SOUND!" (And I speak from experience!) THOSE words will make you run like the wind!
Please keep us posted. Be well, Toots!
Linda

I think that you can now wear a watch that would record your heart rate while you are sleeping..

Thank you trh5732. Being of a "certain age," I'm not as aware of all the devices, apps and gadgets out there that are capable of doing amazing things like monitoring our health while we sleep. I appreciate the education!

I have had a recent pacemaker implanted and set so my heart will not go below 40, as it can also pause at low rate, leading to fall or passing out. It may not always show up on routine periodic EKG. Long term 2 week monitor likely would pick it up. Does it go low in the day? could you print EKG when it goes low in the day and send to your MD?

Hi @abbyd13,

An excessively slow heartbeat can mean that your heart does not deliver enough oxygen and other nutrients throughout your body.

If you’ve followed an unbalanced or calorically low diet long enough for your body to adapt to a malnourished state, resuming a normal diet (weight cycling) can cause your phosphorus, magnesium and potassium levels to drop. This leads to a higher risk of heart failure, heart attack or stroke, according to new research published in the American Heart Association’s journal:
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.034978
I thought you might be interested in reading some key notes from the study –
To measure the effect that weight cycling can have on the body, researchers tracked 6,748,773 people from 2005 to 2012. Participants were generally healthy at the start of the study, did not suffer from diabetes, high blood pressure, high cholesterol levels, or previous heart attacks. By the end of the study, 54,785 people had died, 22,498 had a stroke, and 21,452 had a heart attack.

Those whose weight, blood pressure, cholesterol, and blood sugar levels fluctuated, were 127 percent more likely to die, 43 percent more likely to have a heart attack, and 41 percent more likely to have a stroke.

According to the senior author of the same study, if doctors detect any variability, it may be time to step in and assess the patient’s eating patterns and lifestyle habits.
https://newsroom.heart.org/news/yo-yoing-weight-blood-pressure-cholesterol-and-blood-sugar-readings-may-raise-heart-attack-and-stroke-risk
I hope this sheds more light on why your doctor is concerned about your diet, @abbyd13?

I think you need an other opinion. Your eating disorder is on your medical record and that is why your Doctor is saying you are not eating enough. Find a new Doctor.
My resting heart rate is also low, as low as 35 when I am sleeping. Normal heart rate during the day is around 50. I am a very active person too. I was also a runner.