Preceptor told HTN patient to keep heart rate below 160 bpm. Any explanations?

[OnePunchBiopsy]

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Last week my IMED preceptor told a 55 y/o male triathlete (newly diagnosed with essential HTN) to keep his HR below 160 while exercising. When the patient left I asked him about this rate control and he basically told me that it is something he tells HTN patients who exercise a lot.

Patient does not have any Hx of cardiac arrhythmias.

I've searched UpToDate and my IM textbook and cannot find anything, and it has been bugging me all weekend.

Any explanations?

 

[Summerlax2016]

I am only an undergrad, but in my 200 level bio class yesterday my teacher said that anything higher than your "max heart rate" could cause damage. Gave us the formula to be 210-age in years which would be about 155bpm for that guy, so maybe that is it? Not sure why the "cap" on it though.

 

[cbrons]

I am only an undergrad, but in my 200 level bio class yesterday my teacher said that anything higher than your "max heart rate" could cause damage. Gave us the formula to be 210-age in years which would be about 155bpm for that guy, so maybe that is it? Not sure why the "cap" on it though.

lol
Well not everything attendings say makes sense btw. Might be his way of telling the guy to back down on the extreme exercise addiction.

 

[Stagg737]

Does the patient have a personal or family history of arterial dx other than HTN? Stroke? Aneurysm? If FH is negative and he doesn't fit some kind of risk factor idk why he'd pick a seemingly arbitrary number other than what cbrons said.

 

[OnePunchBiopsy]

Does the patient have a personal or family history of arterial dx other than HTN? Stroke? Aneurysm? If FH is negative and he doesn't fit some kind of risk factor idk why he'd pick a seemingly arbitrary number other than what cbrons said.

No Hx or FHx of stroke or aneurysms. He was a pretty fit dude with solid genetics. It really struck me as odd that the doc said that. The guy was doing sprint and olympic triathlons, wasn't gearing up for an iron man or anything.

Gave us the formula to be 210-age in years which would be about 155bpm for that guy, so maybe that is it? Not sure why the "cap" on it though.

While checking my book, it says 220-age is max HR outside of an arrhythmia, which gave me 165, which perplexed me further.

 

[Psai]

Ask your preceptor and let us know. Not everything your teachers say is legit though

 

[QualityProcess]

While checking my book, it says 220-age is max HR outside of an arrhythmia, which gave me 165, which perplexed me further.

maybe he was just telling the patient to not try to exceed the max heart rate for his age and miscalculated

 

[Dral]

My thoughts:

Think of it from a physiological standpoint. If he has naturally higher pressure, his resting rate could be lower than it 'should be'. Think of the opposite...if someone's pressure is low, their receptors detect that and respond by increasing rate to increase flow.

Now in this guy's case, his pressure is higher, so his receptors could possibly be keeping his rate lower than it would naturally be if he didn't have EHT...his pressure if keeping flow enough so that his rate doesn't have to be as high to maintain is physiological flow/perfusion. So if he lives with a rate lower than it would be...if his rate gets up to above 160 that's a larger increase in rate compared to if he was at his natural rate without EHT.

Natural rate: 60: 160-60= 100 increase rate from baseline
Rate with EHT: 50: 160-50= 110 increase rate from baseline


Just a theory as I'm not a cardiologist or physiologist.

 

[Donald Juan]

While checking my book, it says 220-age is max HR outside of an arrhythmia, which gave me 165, which perplexed me further.

So, are you perplexed why he said 160 and not 165? Because I don't think that's a big enough difference to be meaningful; maybe he just tells everyone in their 50's 160, everyone in their 60's 150, etc.

Or, are you just questioning this whole max heart rate while exercising thing? Because it seems to be "common knowledge" according to all of the heart monitoring fitness bands and treadmills in the world, but I'm not really sure where it comes from or how well researched the concept is.

 

[VisionaryTics]

Oh my god who cares

 

[Donald Juan]

Oh my god who cares

Doctors who need to council their patients with cardiovascular risk factors on safe exercising.

 

[sloop]

My thoughts:

Think of it from a physiological standpoint. If he has naturally higher pressure, his resting rate could be lower than it 'should be'. Think of the opposite...if someone's pressure is low, their receptors detect that and respond by increasing rate to increase flow.

Now in this guy's case, his pressure is higher, so his receptors could possibly be keeping his rate lower than it would naturally be if he didn't have EHT...his pressure if keeping flow enough so that his rate doesn't have to be as high to maintain is physiological flow/perfusion. So if he lives with a rate lower than it would be...if his rate gets up to above 160 that's a larger increase in rate compared to if he was at his natural rate without EHT.

Natural rate: 60: 160-60= 100 increase rate from baseline
Rate with EHT: 50: 160-50= 110 increase rate from baseline


Just a theory as I'm not a cardiologist or physiologist.

Baroreceptors reset to operate at higher pressures in longstanding hypertension. I mean think about it . . . There's a reason every HTN patient isn't brady.

 

[TooMuchResearch]

Last week my IMED preceptor told a 55 y/o male triathlete (newly diagnosed with essential HTN) to keep his HR below 160 while exercising. When the patient left I asked him about this rate control and he basically told me that it is something he tells HTN patients who exercise a lot.

Patient does not have any Hx of cardiac arrhythmias.

I've searched UpToDate and my IM textbook and cannot find anything, and it has been bugging me all weekend.

Any explanations?

Medicine is full of dogma and outdated knowledge, but this one sounds more like something your preceptor made up.

 

[Instatewaiter]

Last week my IMED preceptor told a 55 y/o male triathlete (newly diagnosed with essential HTN) to keep his HR below 160 while exercising. When the patient left I asked him about this rate control and he basically told me that it is something he tells HTN patients who exercise a lot.

Patient does not have any Hx of cardiac arrhythmias.

I've searched UpToDate and my IM textbook and cannot find anything, and it has been bugging me all weekend.

Any explanations?

Nope. Sounds bogus to me.

 

[Psai]

Doctors who need to council their patients with cardiovascular risk factors on safe exercising.

Yes because people who develop cardiovascular risk factors are the ones we worry about concerning their overenthusiastic exercising

 

[Instatewaiter]

Yes because people who develop cardiovascular risk factors are the ones we worry about concerning their overenthusiastic exercising

Haha so true

 

[Terry Toma]

Yes because people who develop cardiovascular risk factors are the ones we worry about concerning their overenthusiastic exercising

Serious endurance athletes may be at increased risk. Running 20-30 miles per week is great for your heart. Running 80+ mpw (like many collegiate runners and serious hobbyists) isn't. Some research suggests that competitive running is worse than being sedentary from a cardiovascular risk perspective. As a runner myself, I'm not as familiar with tri training, but I wouldn't be surprised if an analogous level of tri training led to similar cardio issues.

Don't know if that's involved in the thinking of the preceptor under discussion. Just saying that it's not such a silly idea to worry about cardiovascular risk factors in people who are "overenthusiastic" about exercising.

 

[OnePunchBiopsy]

As a runner myself, I'm not as familiar with tri training, but I wouldn't be surprised if an analogous level of tri training led to similar cardio issues.

Don't know if that's involved in the thinking of the preceptor under discussion. Just saying that it's not such a silly idea to worry about cardiovascular risk factors in people who are "overenthusiastic" about exercising.

I didn't really picture him as "overenthusiastic about exercise," but you do bring up a good point! There are definitely diminishing returns regarding how far someone runs competitively.

As far as triathlons go the distances that the guy mentioned did not seem unreasonable:
Sprint = 0.5mi (750m) swim, 12.4mi (20km) bike, 3.1mi (5km) run
Olympic= 0.93mi (1.5km) swim, 24.8mi (40km) bike, 6.2mi (10km) run


On a further note, I will see this preceptor this afternoon and see if he has an answer!

 

[Zebra Hunter]

nm

 

[OnePunchBiopsy]

Well I have an answer.

My preceptor told me that in HTN patients, diastolic dysfunction of the left ventricle and left ventricular hypertrophy are associated with ventricular and supraventricular arrhythmias. So he told the patient not to exceed a rate of 160 because that is his theoretical max heart rate.

Makes sense to me. Any thoughts?

 

[ACSurgeon]

Oh my god who cares

Nurses. Nurses always care.

 

[Zebra Hunter]

Well I have an answer.

My preceptor told me that in HTN patients, diastolic dysfunction of the left ventricle and left ventricular hypertrophy are associated with ventricular and supraventricular arrhythmias. So he told the patient not to exceed a rate of 160 because that is his theoretical max heart rate.

Makes sense to me. Any thoughts?

So he asks his patients not to exceed a heart rate that is theoretically impossible to exceed unless experiencing a tachy-arrythmia. That makes absolutely no sense.

 

[Instatewaiter]

Well I have an answer.

My preceptor told me that in HTN patients, diastolic dysfunction of the left ventricle and left ventricular hypertrophy are associated with ventricular and supraventricular arrhythmias. So he told the patient not to exceed a rate of 160 because that is his theoretical max heart rate.

Makes sense to me. Any thoughts?

Well it sounds like malarky.

While it is true that with hypertension you get LVH which can cause some diastolic dysfunction the supraventricular arrhythmias come from atrial stretch. As your diastolic dysfunction your LA pressure rises (ie LVEDP) causing atrial stretch and atrial arrhythmias (SVT). Being in better cardiovascular shape, even despite hypertension will keep your LVEDP low and prevent this atrial stretch. I will also improve your BP.

In terms of max heart rate, this is determined by your intrinsic conduction which slows with age. The 220-age is just one of many formulas which estimate what the max heart rate is. You cannot raise your heart rate above this rate unless you it is d/t an arrhythmia. So telling someone to keep their heart rate below what they can actually raise their heart rate to is kind of ridiculous and arbitrary. If his max HR actually were 160, it would be impossible for him to raise his HR above this level.

Overall, sounds made up.

 

[Mad Jack]

He's probably just going by the AHA guidelines on exercise, and using the commonly utilized formula for maximum heart rate:

http://www.heart.org/HEARTORG/Getti...cs/Target-Heart-Rates_UCM_434341_Article.jsp#

Going higher than that won't kill you, but the going theory is that it isn't doing you any favors to push yourself to 100% of your limits.

 

[TooMuchResearch]

Well I have an answer.

My preceptor told me that in HTN patients, diastolic dysfunction of the left ventricle and left ventricular hypertrophy are associated with ventricular and supraventricular arrhythmias. So he told the patient not to exceed a rate of 160 because that is his theoretical max heart rate.

Makes sense to me. Any thoughts?

If it's a max heart rate, one shouldn't need counseling to avoid going above it. It's a rough physiologic max rate, not a rate to avoid going over.

It's more of a reminder that if a 70 year old guy walks into your clinic or ED with a rate of 160, it's probably not physiologic. If his rate is 150, ask him if he just maxed his 800 m on the way in, but it's probably SEPSIS (trigger CMS core measure).

 

[NotAProgDirector]

Well I have an answer.

My preceptor told me that in HTN patients, diastolic dysfunction of the left ventricle and left ventricular hypertrophy are associated with ventricular and supraventricular arrhythmias. So he told the patient not to exceed a rate of 160 because that is his theoretical max heart rate.

Makes sense to me. Any thoughts?

This makes no sense.

Sure, HTN --- in some patients --> LVH / HFpEF (apparently the new cool term for diastolic dysfunction) --- in some patients --> SV and V arrythmias.

But the arrows only point to the right. So being tachy from exercise doesn't cause LVH. And being tachy doesn't cause HTN. It will cause your BP to be somewhat elevated while you are exercising, but that's physiologic and harmless.

 

[gmbz]

I do not think heart failure with a preserved EF is the new diastolic dysfunction term. I am missing something here?

 

[OnePunchBiopsy]

This makes no sense.

Sure, HTN --- in some patients --> LVH / HFpEF (apparently the new cool term for diastolic dysfunction) --- in some patients --> SV and V arrythmias.

But the arrows only point to the right. So being tachy from exercise doesn't cause LVH. And being tachy doesn't cause HTN. It will cause your BP to be somewhat elevated while you are exercising, but that's physiologic and harmless.

Thank you for the explanation! While my attending's explanation made "reasonable" sense, I did not think it was medically sound from the beginning. I don't think the patient even had LVH since he was recently diagnosed with the HTN.

 

[StampLicker]

That isn't a suggestion I'm used to hearing, but it sounds like the doc is just trying to get the patient to reduce the force against the patient's higher-than-normal afterload (HTN).