Mtracer

I don't have a specific question on the topic of Heart Rate Reserve (HRR) but was interested in having a discussion about it. For those not familiar with it, it is the difference between your maximum heart rate and your resting heart rate.

In my case, I think I'm a bit unusual in that my HRR is about 120 BPM which is derived from my 185 BPM max and 65 BPM resting. I think I'm also a bit unusual in that I'm 62 years old with a max HR of 185 BPM. And I'm not necessarily sure that's my maximum. It's the highest I've recorded on outdoor rides, but it is also the highest I've hit on indoor rides during ramp tests and I do start to grey out a little bit on those ramp tests. I've actually seen resting a bit lower than 65 BPM a few times. But 65 BPM seems a pretty consistent value.

I've seen reference that HRR is typically between 60 and 100 BPM, mine at 120 BPM would appear to be on the high side and outside the normal range.

I'm a bit curious what others have seen and what people think HRR means in terms of their own fitness. In my case, since my max HR is high for someone my age (62 yr), to some degree this would seem to indicate I simply have a low stroke volume. Same with the resting HR. I've been riding a lot for 4 years, so have reason to think I have good to very good cardio fitness, but my resting HR is not especially low. Again, this would seem to point to a low stroke volume. Which itself seems a bit odd, as the rest of me is pretty large since I'm 6' 2". So, I'm perhaps built more like a moose with a heart like a rabbit.

Anyway, just wondering what others have to say about this.

GhostRider62

They say Max HR divided by Resting HR times 15.2 approximates your VO2 max in mL/Kg.

I'm a few years older than OP. Prior to Long Covid, my Max HR was 183 and resting HR mid 40's. When Covid got me late last Fall, my resting HR was in the high 80's to low 90's and it took 5-6 months to come down to the mid 50's. According to an echocardiogram this Spring, my left ventricle was smaller by around 10-12%, The Cardiology people were happy with this improvement as my HR was now in the normal range, which according to their text books brought down off the mountain by Moses starts at 60 bpm. Of course, I saw the data differently as my snarky comment shows. My morning HRV also sucked.

As my metabolic fitness increases (mitochondria) along with stroke volume, my threshold HR actually drops despite making more power than when less fit.

Percentage difference between max HR and resting HR is supposedly a good proxy for percentage of VO2 max. So, 120 bpm for 60 year old with 180 bpm max and 60 bpm resting HR would be 50% and about equal to VT1 for moderately fit people whereas 60% would be quite fit aerobically. HRR is more related to VO2 max whereas the ability to exercise at higher and higher percentages of HRR (added to the resting rate) equates more to metabolic health or at least how I think of it.

MoAlpha

I'm 67 and my HRR is about 120 bpm too. I'm still pretty fit, but my max and threshold HR have fallen a lot over the past couple of years.

Iride01 

I think you'll find many of us are like you. If you were to tell me that you just started cycling and that you've never done any other cardio fitness activities, then I'd be surprised at your numbers.

I'm only finding out now at 65 yo that I don't seem to top out over 180 bpm like I use to when I was 62 yo. I don't really "train". I do casually look at my numbers and know somewhat what I need to do to maintain or get better at something that is challenging me on my rides.

My resting HR about 40 minutes after climbing six flights of stairs to get to my cardiologist a few days ago was 57 bpm.

Hermes

I am not sure about mine. Resting HR is 55 and sleep HR varies a lot down in the 40s. Max HR has been drifting down over the years...it seems. I am going to say it is 170 but maybe if I did a real 500 meter race it would be more like 180 so I will say 120 HRR and join the gang.

blacknbluebikes 

I think it tells you more about genetics than anything else. My max HR has dropped considerably as I've aged, while my resting HR hasn't gotten too much lower since before cycling. My wife's resting HR is *significantly* lower than mine, not through greater conditioning - her father was a world-class wrestler in college. Good genes.

MoAlpha

Incidentally, a low RHR and a blunted HR response to a moderate exercise challenge are a predictors of a-fib in older folks.

RChung

What is a "blunted" response?

MoAlpha

Less of an increase.

Much cited paper here.

Carbonfiberboy 

For sure. The fitter we get, the higher the risk of AF and IME other heart issues as we age. A bit more moderation seems to be in order. Many of us seem pretty sure that a blunted response is a good thing. More ejection fraction, please! Ventricular wall thickness increases in fit endurance athletes as we put out more power at any given HR percentage.

What I'm curious about is what causes the electrical issues which accompany the high fitness levels of older athletes. What are we wearing out? It seems obvious to me that correlation is not causation.

On the "yes it's possible" side, the oldest rider this year in RAMROD, 158 miles and 10,000', was 85. He came in about 2/3 of the way down the pack. I wish I'd had the opportunity to speak to him but I had a finish line assignment.

Another good thing I noted was that women were coming in way up in the pack this year. Maybe the increased focus on femme races is having an effect or maybe the club is simply having more success at outreach.

vespasianus

I don't know how useful these numbers are. My resting heart rate can be as low as 48-50. My max HR is close to 195 - giving me a HHR of 145. I am a 50 year old guy in OK shape.

Mtracer

I agree, I think in general the absolute numbers anyone has are mostly dependent on their genetics. Obviously resting heart rate will go lower or be lower with exercise. But I assume there are limits to how low any one person can get. I suspect your life's history of exercise plays a big role as well.

I only started cycling about 4 years ago, and while I've had extended periods of time in my life where I exercised regularly, that was nothing like like the regularity, hours, and intensity I've been doing on the bike. It helps to be mostly retired. Likely whatever level of fitness I can achieve or maintain would be different if I had been this active throughout my life.

MoAlpha

Yeah, I don’t really understand the damage to the conduction system either. It’s definitely associated with enlargement and remodeling of the left atrium, but the SA node is in the right atrium. The association with low heart rate, blunted HR response and also high HRV is a little easier for me to grasp. All of these things are related to parasympathetic tone, which decreases the refractory period (the time during which excitation can’t occur) of the atrium, making abnormal rhythm generation more likely. At least that’s my neurologist’s understanding.

Carbonfiberboy 

I'd forgotten that you are a neurologist. Interesting. I've been seeing 3 cardiologists, 2 plumbers and 1 electrician, the only one in the practice. I recently had a pacemaker installed to force my ventricles to beat synchronously with my atria. I also have PVCs, coming in clumps at higher HRs, worrisome. Also very low HRV, especially the parasympathetic side and none of my cardiologists have ever heard of HRV except from me and couldn't care less. I seem to be a zebra as far as these folks are concerned. I tried local sports cardiologists, but they're at the University, busy with young athletes, research, and teaching. So I have a couple stenters and one ablator/pacemaker installer.

Iride01 

Has plumber always been a common and frequently used term for a cardiologist specializing in the physical things of the heart, or is that just recent vouge? I just heard that used for the first time on my recent visit to my "plumber".

MoAlpha

Unsurprising. People here have somewhat unrealistic ideas regarding the interests and attention spans of community docs, especially cardiologists. I think it's fair to say those folks are focused on the very sick and the reimbursable.

Carbonfiberboy 

Steamer

It seems to me that HRR is mostly useful as a metric for evaluating exercise intensity based on heart rate. Specifically, % of HRR. If a person has a max HR of 180, and resting HR of 60, and the HRR is 120. Exercising at 120 would be at 50% of HRR.

More commonly % of Max HR is used, but that ignores the effect of baseline /resting HR, which can vary between two individuals who have the same max HR.

So if a person had a max of 180, min. of 40, and was exercising at 120, they would be at 57% of HRR.

57% of HRR is a higher relative intensity than 50% of HRR. Even though both riders were at 67% of max HR.

Hermes

My cardiologist, who has a significant athlete practice, wanted to see my power files during my last visit. I pulled them up on my phone. Maybe she can charge an addition $75 for review of patients performance metrics.

Actually, I like her a lot. I had a CT scan of my chest for another matter. The pathology report came back on my chest but also included that one of the coronary arteries MAY be calcified. I asked her about the report. She is not happy with radiology putting those notes on patient reports. She says that the heart is beating and the arteries move creating a shadow. It is an unnecessary remark that is troubling for patients and adds no value. There is a special CT scan that she can order that will provide the correct image. She is relying on my performance metrics (every time I do a HIIT session it is a stress test) and any symptoms as well as echo imaging and short term patch rhythm monitoring for heart related pathology, if any. She can always run a nuclear stress test if she wants to. Great doc.

MoAlpha

She sounds like a good one. My wife also saw one for a pre-op evaluation of persistent extra beats and he sent her home with reassurances and no monitor (yay), so they're out there. However, office cardiology is the mouth end of a very profitable commercial organism whose digestive tract ends in the cath lab and the OR. My plan is to avoid it until I'm pretty sure I need it.

MinnMan

At age 62 my HRR is near 135. MHR=180 bpm, though I've only seen it that high twice this year, RHR around 45 bpm.

I might be a candidate for a-fib according to MoAlpha 's criteria. Though I can get my HR up to 180, it's very unusual for me to approach my MHR now. In normal hard efforts, I don't get above about 172. 10 years ago, when my MHR was 184, when doing intervals my HR would go up to 175 (MHR-9) at the end of each effort. Now it may not go above 165 (MHR-15). Also, my RHR was about 50 in those days, and now it's 45. But AFAIK, I don't have any evidence of a-fib.

I've been to cardiologists over the years, but like MoAlpha says, they are mostly just interested in telling me that I have a strong heart relative to the general population and then they're on the next patient with genuine life-threatening heart trouble.

MinnMan

If so, my VO2max is 61. The last time I had mine measured was 8 years ago and from memory I seem to recall that it was in the high 50s, during a time when my training load had been unusually low for quite some time. So maybe that's accurate. I dunno.

I generally haven't paid much attention to VO2max, so I don't have a good feel for what the numbers mean or what I should hope for.

spclark 

Interesting thread (I've just stumbled into) this one.

I'm nearing half-way through my 74th lap around Sol, just this year started cycling once again. Bought a new Kona in April to commute to work (3/4 mile twice a day, three days a week) then remembered how much fun cycling was so I was inspired to 'renovate' the 1972 Motobecane Grand Record roadie I've had since Easter 1972 that sat forlorn, almost forgotten, in the basement after we moved to where we are be ten years this November.

Had a 'mild' infarction on way to work days before my 57th birthday, ~ 90 minutes into my 2 hr. commute on inbound Kennedy expressway. Stopped at ER, had two stents in one cardiac artery by 10 AM. I tend to keep track of what my heart's doing now.

That roadie's got me out riding more than the Kona. It's really hilly where I live now (was 99% flat before) so Strava's a good way to monitor heart rate, elevation changes, mileage and speed. Longest ride to date's been ~ 14 miles on a paved (mild grades) path, otherwise it's secondary (paved) roads outside of town. (My current cardiologist has signed off on this activity with the caveat that as long as there's no discomfort during or after I can continue.)

Right now I've been sitting down for a couple of hours, my RHR is 55. Resting HR runs 53 - 63, sleep ranges from ~ 63 to a low of 49. I note a slow decline in that range after I'd begun the road cycling early this June. I walk around 7 miles every day I pull a full 9 hour shift at work, 3 days a week the last six years. 5'-10" 175#. Old method for calculating MHR (220-74=146) left me worried the numbers I was seeing should be a caution. Newer method (Gellish: MHR = 207-(0.7x age which in my case comes up 155.2) makes me more comfortable with the 165-170 I've been reaching at the tops of some of the climbs I've been pedaling up. Those numbers put my VO2max @ just under 50 for what that's worth; never had it 'officially' measured. (Some ways to measure VO2Max here.)

No evidence of a-fib whilst my sedentary spouse has been on meds for it for going on four years now, Her heart rate has touched 220 bpm in times of high stress like what fear of COVID brought on three years ago.

Will be paying attention to further contributions to this thread.

GhostRider62

Higher intensity vs moderate intensity show higher levels of a-fib. Cardiac MRI with gadolinium contrast suggests myocardial fibrosis in the right side of the heart for endurance athletes at higher intensities. What isn't known to my research is what dose relationship is acceptable, other than moderate is good and too much high intensity is bad.

This is what I do in case anyone is interested

1. I monitor heart rate variability to assess my autonomic nervous system balance (and subjectively monitor sleep and mood) to determine if I might benefit from a HIIT session
2. On long training rides, I do a lap on my Garmin for the first half and then for the second half while monitoring average HR and average Power. If my first half HR and power are on target but HR starts to increase or power drops, such decoupling is a sign to me to pull the plug and either cut the ride short or ride easily home. To put numbers on it, lets say I plan a 3 hour ride at 120 bpm and 200 watts for round numbers. If I start to only make 160 watts at 2 hours, absent brutally hot conditions, this indicates too much of a load on my heart. If my cardiovascular fitness is good, both halves of the ride will be about the same and I might increase the duration of my long ride.

I am curious how others judge their readiness to increase exercise load.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6209018/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7403702/

spclark 

Something I'm interested in too but lack sufficient info to qualify.

Mine's 21ms avg. over the last six months. What's a prudent range for someone my age and condition?