What is a dangerous heart rate?
I was wondering, at what percentage (ie 110%, 120% etc.) of your max heart rate does your cardiovascular system begin to fail?
How hard can you make your heart work before you start to cause damage, and exactly what sort of damage could result?
Also, what are the definite signs that indicate your heart is working too hard?
Last edited by AutumnPolitics; Nov. 30/09 at 06:30 AM.
you can't get to more than 100% of your max heart rate.. your max heart rate is your max. If you get above that then your max heart rate test wasn't done properly.
Also, you won't train so hard that your heart explodes or anything. You might get trouble if you have coronary heart disease, though.
Heart rate is all relative. Example, somebody who's been an avid cyclist for a good portion of their lives will have a higher max heart rate, at even an older age than somebody who say, plays football.
It's all about to how the heart and cardiovascular system has been conditioned, at any age.
Although it has been commonly assumed that better fitness increases one's max heart rate, that is not true. Max heart rate is more dictated by genetics than anything else.
Originally Posted by oicdn
Yes, you CAN have your heart rate go too high - for you. Like someone else said, it is relative. Best way to calculate your maximum heart rate is to take your pulse for at least one minute a day BEFORE getting out of bed for three days. It should give you a pretty good average of your "resting" heart rate or your baseline.
When ppl say 120 or 140%, what they mean is a calculation of your resting heart rate plus your percentage calculation. RHR x 0.2 = 20% of your RHR. Add the number for the 20% to your resting heart rate. For instance, if your RHR is 75:
75 x 0.20= 15, 75 + 15 = 90 (100% + 20%)
Calculate your rates for 30 & 40%. That will give you your target "zone."
If you are over 35, subtract 3; over 45 subtract 4; over 50 subtract 5 for your "zone" calculations. Ie: 90-3=87, so if you are over 35 that would be your personal heart rate.
Now, there isn't a heart rate that is going to cause cardiac shutdown or make your heart explode. However, once you go over your maximum heart rate (150%), you are no longer doing aerobic exercise because your heart can't push out enough oxygenated blood - so you go into anaerobic metabolism. If you are doing cardio workout, going into anaerobic and staying there can be a very, very bad thing. So find your zone and stay in it.
As your endurance increases and your heart muscle and arteries become stronger (and younger), your RHR will drop. This is a good thing.
Some signs that your have been working your heart too hard for too long:
Bradycardia w/ rapid tachycardic response - meaning your HR goes down so far the electrical system in your heart gets shorted and starts to make extra beats. Tachycardia is a deadly arrhythmia. This will not be noticable unless you are resting, not while you are exercising or immediately after. This is actually called "Athletic Cardiomyopathy." But you have to have worked over your max heart rate for many years before it really puts you down.
Hope this helps and doesn't confuse you. I'm an RN, so I call on a different knowledge base than a trainer, so they may have different, and better, information. And if I got anything wrong, then someone is more than welcome to tell me so - I take criticism well.
Last edited by laynicrn; Dec. 06/09 at 01:12 AM.
Reason: Additional information
Did you mean UP here? Also:
Originally Posted by laynicrn
This is actually what prompted me to post this thread... I have suspected I might have a mild form of a condition resembling what you described, for a while.
Originally Posted by laynicrn
A few weeks ago a doctor was inspecting my heart sounds and pointed out that I have a heart murmur - nobody had ever noticed this before, and I was unaware of it.
I have only been training for about 6 months (all prior training I did was quite mild in comparison to what I do now), but I wonder if this is enough time to do the sort of damage you describe - ie, forcing my heart to do too much work and not giving it enough time to adapt, and harden my arteries etc.
I should also point out that I'm prescribed dexamphetamine and I will commonly take a dose shortly prior to working out, or at the end of the day when the medication has built up in my bloodstream. However, I am not certain whether the medication actually does have much if any effect on my heart rate - since I can exercise with exactly the same intensity when I do not have any medication in my bloodstream.
I commonly feel faint and 'spacey' when I work out, but deliberately ignore it and continue to push myself.
My resting heart rate can be 70 - 72 bpm after a week of training, when it is normally 65 - 68.
So anyway, I am wondering if I am doing anything wrong, or if it is fine to continue with what I am doing, considering it's only been 6 months, and I'm only 22 years old.
Stop the madness
First, do NOT continue with what you are doing. <B>GO TO SEE THE DOCTOR!<B> NEVER, EVER ignore what your body is telling you - and feeling "faint and spacey" is your body telling you that something bad is going on. Also, if you are taking any form of amphetamine, you must discuss any exercise regimen with your doctor.
Originally Posted by AutumnPolitics
I would love to say I am not trying to scare you, but I am. Sorry. You are only 22? Stop training now and go see your doctor. Make sure the doctor knows all your symptoms AND that you are on dexamphetamines. Amphetamines put a significant strain on your heart without the added stress of exercise. Also amphetamines can make your heart beat faster without actually pumping out all the blood appropriately.
Look, I'm an RN and have a specific knowledge base about anatomy and physiology and how things work, with and without outside forces, in the human body. And I will admit that there are things that I know nothing about. But the information you have given with your symptoms are, quite frankly, scary. And you need to stop working out and see a doctor ASAP. I am NOT a doctor, your doctor can give you more information about your specific condition than I can. And if your doctor says I am wrong, and clears you to exercise, then so much the better. But your doctor needs to do that, not me.
Hope you get this sorted out sooner rather than later.
Thanks, I really appreciate the heads up Layni.
So, hopefully without sounding too naive or arrogant, it looks like I am facing a choice between long-term health problems and short-term reduction in achievement of my goals.
Am I right in saying this is a choice all athletes face?
Also, I'm not discarding your advice on seeing a doctor completely - I would like to discuss this with a doctor who is knowledgeable in this field, however all of the doctors I know are frustratingly hopeless when it comes to issues like these.
It really seems like more hassle than it's worth to ask my stupid doctors about this.
I understand about doctors, us nurses have our own issues with them.
I would see a cardiologist, preferably a cardiologist that specializes in electrophysiology of the heart. But they are hard to come by, so go see a cardiologist.
I would speak to the doctor that has prescribed the dexamphetamine and discuss a program to taper off that medication, if possible. Don't stop it in one day, though.
In my own experience, I have almost always been able to exert myself as hard as I want without problem. It's not that I believe my body can handle anything, but rather that my body seems to limit itself, sort of like a car with a governor that limits the top speed to prevent engine damage. In a similar manner, if running a quarter mile in X seconds would put my body in danger, it wouldn't matter because my body would naturally limit me to X + 10 second quarter miles. (This is not to say high level of exertion in the heat or after consuming a significant amount of a stimulant such as caffeine wouldn't be dangerous, but I don't exercise in those situations, at least not in an intense way.) It wasn't until a couple years ago that I found dangerous overexertion is possible for me. About 36 hours after giving blood, I thought I was back to normal. I didn't feel woozy even right after I gave blood, so after more than a day had passed, I felt I'd be safe to row. And I probably would have been had I just rowed lightly. But I decided to row at a high level of intensity, which is normally enjoyable and safe for me. And during this row I felt good and was able to perform about the same as normal. However, after I finished my row and stood up, I immediately felt light-headed. My vision went dark and blurry. I sat down and then lied on my back. It took about 20 minutes or so for me to feel like getting up. My assumption is that following my blood donation, my hemoglobin was reduced, and following my workout, I wasn't able to give my brain the amount of oxygen it needs to work properly and that I was close to losing consciousness and would have had I not gotten on my back. It is the only time in my life where I feared for my health without having some sort of illness.
Anyway, I hope Layni and others can clarify the nature of the dangers of overexertion, especially for those who are generally healthy. Is it fair to say that for most people without cardiovascular disease, especially people who are relatively young and who exercise regularly, the concern with overexertion and very high HR is not so much heart failure per se but lack of blood to the brain? Besides feeling faint, what other warning signs are there that one should take it easy?
Am also interested to learn about this, at least so I can have more confidence in my workouts.
Originally Posted by subdude
Can you please clarify what you mean by "athletic cardiomyopathy"? and that thing about the heart rate going so low that the electrical system gets shorted. What is this called and where can I read about it?
Originally Posted by laynicrn
Also, you can't get to 150% of your max HR.. max is max, it's the most you can get. If you get to 150% of what you think your max is, then it isn't your max.
Why is doing anaerobic cardio training a bad thing? What about high intensity interval training, which a lot of people use.. What about 800 meter runs in the olympics?
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