HR Mythbusting

[cbjesseeNH]

When not riding my bicycle with powermeter, I wear a Heart Rate Monitor. The classical advice in texts of the 80s/90s was to not exercise at 90%+ HRMax as the risk of injury is greater. This risk was not well explained and the advice may have been directed at those seeking initial fitness from sedentary lifestyles, but no such disclaimers were made - probably due to legal concerns.

Now one sees information from highly regarded sources indicating normal training levels are expected to achieve HR > 90% HRMax http://www.cyclingpeakssoftware.com/power411/levels.asp

Is/was there any support for this claim of added "risk" at > 90% HRMax?

If not, is there any support for the lack of any added "risk" in exercising at > 90% HRMax? (for an otherwise healthy individual who trains hard).

Even further, is there evidence for benefit of training at 90%+ HRMax? (Which just might be that to acheive training at FTP or higher power, HR will likely exceed 90% HRMax).

Practically speaking, I do it all the time, as do others, I'm sure, but I was looking for some studies that address the matter more thoroughly than anecdotal experience.

What got me wondering, is when I'm in a hot indoor spinning studio, cranking at a HR greater than I would expect if riding known power ranges on a bike with adequate colling, am I getting some sort of excessive "physiological strain" from the temperature-induced high HR but less gain from the lower power?

 

[Snuffleupagus]

You're going to see stresses of 90% or greater in a race situation right?

The goal of training should be to prepare you for the efforts you're going to subject yourself to...if anything training your body to handle maximal efforts will keep you safer when doing those same maximal efforts in a group.

 

[acoggan]

Is/was there any support for this claim of added "risk" at > 90% HRMax?

Even in a healthy individual, the risk of a significant cardiac event (e.g., heart attack) increases with increasing exercise intensity. That said, in a healthy person the risk of such complications is very low, such that high intensity exercise is not contraindicated.

 

[Pendejo]

Even in a healthy individual, the risk of a significant cardiac event (e.g., heart attack) increases with increasing exercise intensity. That said, in a healthy person the risk of such complications is very low, such that high intensity exercise is not contraindicated.

Exactly. If it doesn't kill you it will make you stronger!

 

[cbjesseeNH]

I did find the following: RPE drift during cycling in 18 degrees C vs 30 degrees C wet bulb globe temperature (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17369793&ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum) which suggests RPE was higher (as was HR) at higher temperatures. What I'm looking for is whether the next day's ride is compromised by the prior day's ride at high temperature.

While we've had hot rides, I really can't say whether a ride at 90F instead of 70F had longer lasting recovery impact.

 

[iliveonnitro]

I did find the following: RPE drift during cycling in 18 degrees C vs 30 degrees C wet bulb globe temperature (http://www.ncbi.nlm.nih.gov/sites/entrez?Db=pubmed&Cmd=ShowDetailView&TermToSearch=17369793&ordinalpos=5&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum) which suggests RPE was higher (as was HR) at higher temperatures. What I'm looking for is whether the next day's ride is compromised by the prior day's ride at high temperature.

While we've had hot rides, I really can't say whether a ride at 90F instead of 70F had longer lasting recovery impact.

Wouldn't it be the opposite? Riding in 90F heat makes L5+ work nearly impossible for me (except race situations) meaning that the intensity is usually lower than that which is possible on a 70F day.

 

[Sillyoldtwit]

Even in a healthy individual, the risk of a significant cardiac event (e.g., heart attack) increases with increasing exercise intensity. That said, in a healthy person the risk of such complications is very low, such that high intensity exercise is not contraindicated.

How does this square with RD's philosophy that the heart will take anything you throw at it? That is, other things will give up ghost before the heart lets you down.
Apologies to RD if I've misquoted him.

Naturally, as I'm a few weeks away from 65 now, it would be nice to know that I'm not heading for a

significant cardiac event (e.g., heart attack)

Do you have the time Andy to clarify what you are saying in your short passage - perhaps explaining (with some evidence) in more depth?
And is the risk greater for the older cyclist?

I'm sure your statement has raised alarm bells in other senior citizens' minds, if not in the younger cyclist too.

Tyson

 

[Pendejo]

It's just a statistical fact that your heart attack risk goes up with age, and is higher during exercise, and is proportional to the stress on the heart. You can't get away from that. During a treadmill/stress test they monitor your heart as the exertion increases - the heart may function normally until a certain stress level is reached.

And even if your heart has always functioned normally at a certain elevated HR, it's not a guarantee that it won't go on strike the next time you hit that HR.

The bottom line is this: in a given moment, your risk of dropping dead while exercising is greater than if you were inactive. But if you exercise your risk of dropping dead over X number of years is lower than if you don't exercise.

I'm afraid RD's dictum that the heart will take anything you throw at it is wrong: it does, until it doesn't.

 

[Sillyoldtwit]

It's just a statistical fact that your heart attack risk goes up with age, and is higher during exercise, and is proportional to the stress on the heart. You can't get away from that. During a treadmill/stress test they monitor your heart as the exertion increases - the heart may function normally until a certain stress level is reached.

And even if your heart has always functioned normally at a certain elevated HR, it's not a guarantee that it won't go on strike the next time you hit that HR.

The bottom line is this: in a given moment, your risk of dropping dead while exercising is greater than if you were inactive. But if you exercise your risk of dropping dead over X number of years is lower than if you don't exercise.

I'm afraid RD's dictum that the heart will take anything you throw at it is wrong: it does, until it doesn't.

Very comforting Pendejo!!! Maybe I won't even see this guy coming.

 

[frenchyge]

Very comforting Pendejo!!! Maybe I won't even see this guy coming.

If you ride fast enough, he'll never catch you.

 

[Sillyoldtwit]

It's just a statistical fact that your heart attack risk goes up with age, and is higher during exercise, and is proportional to the stress on the heart. You can't get away from that. During a treadmill/stress test they monitor your heart as the exertion increases - the heart may function normally until a certain stress level is reached.

And even if your heart has always functioned normally at a certain elevated HR, it's not a guarantee that it won't go on strike the next time you hit that HR.

The bottom line is this: in a given moment, your risk of dropping dead while exercising is greater than if you were inactive. But if you exercise your risk of dropping dead over X number of years is lower than if you don't exercise.

I'm afraid RD's dictum that the heart will take anything you throw at it is wrong: it does, until it doesn't.

I think it is time we got this thread into some perspective.
Things in life, be it your car, your iPod, or your heart don't go on strike for no reason. I think I'm safe in saying there is always some underlying reason.
In the case of the human heart, perhaps there is a congenital defect, a hardening of the arteries, fatty deposits on the walls of the arteries etc.
Of course individuals differ, but I think the rate at which your heart recovers from strenuous excercise is a good indicator of the health of the organ.
My heart after being worked at 160BPM (high on average for someone of 65) drops like a stone to under 120bpm in about 45 secs.
With all due respect Pendejo, I feel you have perhaps over simplied matters, and dare I say, been overly alarmist.
When I was younger, a good friend I used to run with everyday, upon reaching the ripe old age of 30, decided he should quit running because he was concerned it might be damaging his heart.
He is still alive but grossly overweight, and his worries were probably unfounded. Yes, he's managed the quantity, but what about the quality?!?!?

Tyson

 

[cbjesseeNH]

Digging through my HR books from the 80s/90s, I find that the more scientific and exercise physiology ones don't have any warnings, but that the Sally Edwards ones do, but mostly mentioning the potential for overuse injury rather than a Major Adverse Cardiac Event (MACE).

I was, in any event, more interested in non-lethal negative stress on training efficacy rather than "The Big One" or damage to the heart itself.

My inquiry seems to evolved to more a question of whether, when HR is eleveated into the 90%+ range by environmental factors (heat, etc), rather than power output, is the accompanying elevated RPE associated with an expected longer recovery time the next day?

That is, if a standard training ride (say, a loop you often ride solo) at given normalized power usually elicits HR in in 90%+ only when bashing the steep section(s) and/or intervals - but you find HR at 90%+ on the shallow grades when it's 90-95F and humid, when it's usually 75-85%, do you need to cut wattage to avoid lasting effects on recovery over the next 48hr?

I guess if you expect hot rides/events, you might want to train for them to accomodate to heat, but I'm more thinking the exceptional day(s) when the highs spike. You can push it to the point of failure, but do you get added training effect from elevated HR/RPE without elevated power, get none, or actually reduce/inhibit the training effect by the higher physiologcal "cost" of a hot ride?

Not quite the same things as watching a horror flick to elevate HR, as you are exercising and pushing RPE and HR, but not pushing Power.

 

[frenchyge]

My inquiry seems to evolved to more a question of whether, when HR is eleveated into the 90%+ range by environmental factors (heat, etc), rather than power output, is the accompanying elevated RPE associated with an expected longer recovery time the next day?

If I'm reading you correctly, I'd say yes the recovery time will be longer. I know that when I ride hard on a hotter day then it takes my body longer to come around, but see below.

I guess if you expect hot rides/events, you might want to train for them to accomodate to heat, but I'm more thinking the exceptional day(s) when the highs spike. You can push it to the point of failure, but do you get added training effect from elevated HR/RPE without elevated power, get none, or actually reduce/inhibit the training effect by the higher physiologcal "cost" of a hot ride?

The physiological stress may be higher because of the heat, but that doesn't increase the training effect of the ride. Just because your body is working hard to keep itself cool doesn't mean that your leg muscles are going to adapt for greater power as a result. As you say, though, if you expect the heat to be a factor in your events, then it would be a good idea to train in those conditions so that your body can adapt in other ways (besides pushing the pedals harder) for better performance during those events.

 

[frenchyge]

I think I'm safe in saying there is always some underlying reason.

I think you're right, although it may not known or may be an interaction of multiple effects which makes it hard to pin down to a specific 'cause'.

In the case of the human heart, perhaps there is a congenital defect, a hardening of the arteries, fatty deposits on the walls of the arteries etc.

Perhaps, although those tend to be included as risk factors since they don't necessarily cause the heart to suddenly stop functioning. People have heart attacks at many different ages and under all types of situations, so it's probably a bit difficult to pin down a specific, common cause.

While I agree with the statement that you quoted from RD as a pithy, practical guideline for HR cycling training, I wouldn't take it as comprehensive medical advice.

 

[Pendejo]

I think it is time we got this thread into some perspective.
Things in life, be it your car, your iPod, or your heart don't go on strike for no reason. I think I'm safe in saying there is always some underlying reason.
In the case of the human heart, perhaps there is a congenital defect, a hardening of the arteries, fatty deposits on the walls of the arteries etc.
Of course individuals differ, but I think the rate at which your heart recovers from strenuous excercise is a good indicator of the health of the organ.
My heart after being worked at 160BPM (high on average for someone of 65) drops like a stone to under 120bpm in about 45 secs.
With all due respect Pendejo, I feel you have perhaps over simplied matters, and dare I say, been overly alarmist.
When I was younger, a good friend I used to run with everyday, upon reaching the ripe old age of 30, decided he should quit running because he was concerned it might be damaging his heart.
He is still alive but grossly overweight, and his worries were probably unfounded. Yes, he's managed the quantity, but what about the quality?!?!?

Tyson

No, Silly, I'm not being alarmist at all. I'm just stating medical facts. I'll be 61 this month and, just like you, I'm out there busting my butt (and stressing my heart!) to lower my TT times. I don't worry about a heart attack at all (even though my dad died from a heart attack at 52, my mom had bypass surgery in her 70s, and my kid brother had bypass surgery in his late 40s) because I take great comfort in the fact that I'm much more likely to die from a car hitting me.

Also, studies have shown that most heart attacks occur in the morning, so I always sleep until noon just to play it safe.

Listen, if we're lucky we'll only suffer silent heart attacks. The only symptom is that you feel friggin great.

 

[BikingBrian]

Very comforting Pendejo!!! Maybe I won't even see this guy coming.

Hey, what better way to go, then doing something you love?
It sure beats sitting around in a recliner waiting for the inevitable

 

[Pendejo]

Hey, what better way to go, then doing something you love?

I'd rather go doing something I hate.

 

[Sillyoldtwit]

I'd rather go doing something I hate.

Sorry PD, I don't follow your logic there. I certainly don't want to go whilst cleaning the car or doing the

. I have to agree with BikingBrian - to go when you're putting every ounce of energy into something you love is the best way - quick and sharp with a smile on your face.

Btw PD, to me with your family background riding hard like you do (assumption) you're a hero. The male side of my family have all lived to a ripe old age. I suppose it's feasible I could break that trend, but I'm not going to let it worry me.

Also I read somewhere, that most people die in bed, so that is why I sleep on a futon. TYSON

 

[Pendejo]

Sorry PD, I don't follow your logic there. I certainly don't want to go whilst cleaning the car or doing the

. I have to agree with BikingBrian - to go when you're putting every ounce of energy into something you love is the best way - quick and sharp with a smile on your face.

Btw PD, to me with your family background riding hard like you do (assumption) you're a hero. The male side of my family have all lived to a ripe old age. I suppose it's feasible I could break that trend, but I'm not going to let it worry me.

Also I read somewhere, that most people die in bed, so that is why I sleep on a futon. TYSON

Well, if I'm in the middle of doing something I love, I sure would like to live long enough to finish it. And if I'm in the middle of doing something I hate, hell, why not head for the exit then? But as Woody Allen once said, "I don't want to be immortal because of my work - I want to be immortal by not dying."

As for my family background, yes, all three members of my immediate family suffered heart disease at an early age. But I've always been a rebel, so instead of heart disease I decided to get cancer - diagnosed with stage IV chronic leukemia at age 50. It's considered incurable, and at that time they estimated that, with luck, I could last five more years.

I figured that being in the process of dying was a decent-enough excuse to get lazy, so I did exactly that for two years. But then the chemo was over and I was feeling fine and skinny-little me was actually beginning to show signs of a gut, so I decided I no longer had a good excuse for being out of shape.

I got back on the bike, got back into shape, then started doing TTs and training seriously. Two years after getting back on the bike I placed second (age-group) in the Florida state finals for the 10K TT, and continue being in the top two or three in the state. I'm now 61 and, at least macroscopically, am perfectly healthy. I honestly believe that strenuous exercise generates some sort of chemical changes in the body that help fight disease, including cancer. Certainly there have been many studies that hint at that.

So I guess in some sense my efforts have been heroic, but in my opinion anybody who trains hard in an aerobic sport is a hero, and the older you are the higher you go on the hero scale. As for you, Ty, it won't be long before they have to add you to Mount Rushmore.

 

[Beastt]

It's just a statistical fact that your heart attack risk goes up with age, and is higher during exercise, and is proportional to the stress on the heart. You can't get away from that. During a treadmill/stress test they monitor your heart as the exertion increases - the heart may function normally until a certain stress level is reached.

And even if your heart has always functioned normally at a certain elevated HR, it's not a guarantee that it won't go on strike the next time you hit that HR.

The bottom line is this: in a given moment, your risk of dropping dead while exercising is greater than if you were inactive. But if you exercise your risk of dropping dead over X number of years is lower than if you don't exercise.

I'm afraid RD's dictum that the heart will take anything you throw at it is wrong: it does, until it doesn't.

Kudos on your achievements and having overcome cancer. We can all only hope that you never again have to deal with the ominous prognosis of such a disease.

As concerns some of your comments about heart attacks, I may be going out on a limb here but I need to ask; do you know what a heart attack is and what it isn't? There are many types of serious cardiac events. Heart attack (myocardial infarction), is just one of them and it can't happen just from applying a strain to the heart. It's also not just a natural side-effect of age. There are numerous cultures around the world with longevities in the 90s and up where heart attacks are almost unheard of. They are, for the most part, completely avoidable but you first have to give up the notion that Western diets are in any way heart-healthy.

I have to agree with a few other posters here, it may be possible to simply stress an older, but healthy heart, to the point of suffering a serious cardiac event. But the idea that age plus stress can automatically lead to a "heart attack" seems to ignore the mechanism of a heart attack. Unless the circulatory efficiency of your coronary arteries has been compromised, a heart attack won't just happen. If you can go out, apply stress to your heart and induce a heart attack, you weren't all that far from having one to begin with. It was just a matter of time and fully detectable -- even reversible.