Changes in heart rate over 3 years
Quick question for the team:
I understand that a lower resting heart rate is a better thing - mine has dropped a bit in my 3 years of triathlon from hi 50's to my current 51-52. But, my z5 hr (and other upper zones especially), have risen over the bast 3 years. Example, is that during 5k run test/race my avg hr has gone from low 160's to current 175. I might note that my 5k times have dropped in that period from about a 27' 5k to 20' 5k. But, although this is hard to measure in retrospect, I "think" effort was the same. I was also 200lbs+ then and now 165lbs. So, I guess there are a few factors here. Bike hr has changed too in the same regards, but maybe not as drastically.
Question is, what does this mean? Is it beneficial to have a higher hr in any zone vs a lower hr, given other variables remain constant? I am also 3 years older and know that generally, hr rate slows with age.
Just some thoughts before my Sunday morning run.....
I understand that a lower resting heart rate is a better thing - mine has dropped a bit in my 3 years of triathlon from hi 50's to my current 51-52. But, my z5 hr (and other upper zones especially), have risen over the bast 3 years. Example, is that during 5k run test/race my avg hr has gone from low 160's to current 175. I might note that my 5k times have dropped in that period from about a 27' 5k to 20' 5k. But, although this is hard to measure in retrospect, I "think" effort was the same. I was also 200lbs+ then and now 165lbs. So, I guess there are a few factors here. Bike hr has changed too in the same regards, but maybe not as drastically.
Question is, what does this mean? Is it beneficial to have a higher hr in any zone vs a lower hr, given other variables remain constant? I am also 3 years older and know that generally, hr rate slows with age.
Just some thoughts before my Sunday morning run.....
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Comments
Resting HR, and max HR/zones are two different things. The resting HR is more as reflection of how big your heart is. For those of us who did a lot of interval training in our teens, say swimming or track or some team sports, we probably have a lifelong head start on having a larger heart. Larger heart means more blood volume is pumped per beat, means slower resting HR is possible. For those who haven't done hard interval work ever or for a long time, their hearts have room to grow, and so the resting HR will drop.
The max HR is showing different things, like compliance (kind of like elasticity), hormone and neuro responses, et al. Again, that can be trained over the short term. Long term, as you not, the Max HR possible will slowly drop after about age 35-40.
The heart is a muscle, and like our skeletal muscles, it has responses to training which include growth in total size, growth in blood vessels within the muscle, and increases in efficiency of contraction. Just like spending time in the weight room can make your other muscles bigger and stronger, the same thing happens to the heart when we train it by asking it to supply more blood/O2, faster.
So what you're seeing is a sign your training is working. Early in one's training curve, the heart is a rate limiter, so these effects are more likely. Later on, it's the skeletal muscles that are the limiter, so we see the bulk of training effect in them.
Thanks for the great response.
If ventricular growth (hypertrophy) gets beyond a certain point things like stiffness and lesser compliance can creep in. Those things are reversible up to a point. That point, however, is usually impossible to determine until you've passed it. Last year, after IMMT, my doc took a routine ECG and was surprised at what appeared to be a much larger ventricular size than he expected. Straight to the cardiologist for an echocardiogram. Fortunately he declared my echo to be 'boring' - such a treasured response I could not have imagined. Everything looked fine. He said lean male athletes often have false positives on ECGs due to the stronger ventricles and the lack of fat tissue between the electrode and the heart allowing a bigger voltage reading. If there really had beeen a problem it was game over for at least several months to see if (and hope) that the cardiac issues went away.
This is a great question, and one I have researched but never found an answer to my satisfaction. I have the exact opposite experience...
I came "off the couch" at age ~36 and started road biking. Quit golfing and became an avid/addicted road cyclist. The higher HR I have ever seen was only 173, and I vomited upon cresting that steep hill. I used to routinely see high 150's/low 160's in Z4/Z5 hard efforts. I now rarely break 150, yet I have been consistently training and getting faster/smarter/etc. over the past 6 years. Started doing tris about 1 1/2 yrs ago and joined EN a little over a year ago. I look at lots of the fast folks in the haus' training/workout files. What I have found is that almost all (if not all) of the "fast" folks have much higher HR in Z4/5 than I can manage. BTW, my resting HR is about 54. I did no endurance training as a youngster (baseball, church league softball/basketball/flag football). I am otherwise completely healthy.
The common formula cited for max HR is 220-age, but this is of course just the mean of a bell-shaped curve....many will be above or below that a bit. What I find interesting, is despite all of the hard work I am now doing in EN (I test per protocols, train per the plans as written, and then do some hard hill work on the bike when not in race prep months) I have not seen a HR anywhere near 173 in over a year. I'll see low 160's towards the end of an FTP test and/or 5K TT. Once I get above ~165, the lights start to dim and I very quickly will implode. Sometimes I wonder if this is mental....am I seeing a high number, associating that with something I cannot continue to see, and therefore my brain tells my body I must stop? I think the answer is no...I often don't notice the numbers during these hard efforts....but once I do, maybe it's mind over matter? I think some of us just can't suffer (physiologically speaking) as well as others.
I know that stroke volume, preload/afterload, compliance are all factors in cardiac output, etc., but the trend is hard for me to ignore. I feel like I genetically can never be "fast", b/c I just can't train at a high enough HR to be "fast".
Just my random musings...
@ Jeff - Yeah, your HR #s seem a little low for someone of your age ... they actually are pretty close to mine, except I have a resting HR of 40 +/-. I have always understood that max HR is (a) a genetic and age related thing and (b) can not be increase by training; the reverse may actually be true. Pulled from a Joe Friel blog post:
A review of the literature by Zavorsky of the University of British Columbia in Vancouver showed that MHR declines as aerobic capacity (VO2max) increases (Zavorsky, G.S. 2000. Endurance and possible mechanisms of altered maximum heart rate with endurance training and tapering. Sports Med 29(1):13-26).
So as you become more fit in the lead-up to your race you might expect to see lower heart rates at the high end. The reverse of this is also true. As fitness declines MHR increases. The review reported 3% to 7% shifts with training and detraining.
If you are working to the point of feeling like you're going to black out, I don't think you have any problems with the ability to push yourself to your max.
My notes about changes in heart rate:
That said, it's important to note: