Decrease in HR MAX as fitness increases

[attiec]

Since my 40'ies, I've noticed that my max hr drops during the training season as I get fitter. I would also notice a dramatic drop in my aerobic limit hr (at same effort) during the same period. As I get older my max hr is dropping, which is to be expected, according to all literature around this....BUT

 

The question that I have never really got an answer to is - why would my max hr drop significantly as I get fitter. This is supposed to be genetically fixed and most articles only point to slight changes when cross-training in other disciplines (Eg. running vs cycling)

 

It is not a question of it just being easier because you are fitter either. After many years of cycling (age now 60), I know when the body is telling me when I'm working close to or at max. The other day I chased a youngster on a road bike, while I was on a MTB. Got to absolute max effort whilst doing >55kph on fairly level road. My max HR for this effort was given as 171bpm by my HRM. Earlier in the season I regularly saw 185bpm. This is a 15 beat drop!!

 

Anybody that had the same experience or can point me to literature that clarifies this phenomena??

[milky4130]

What I noticed when I'm fresh/unfit, it's easy to reach a new MHR, 191bpm in my case vs the usual 185bpm. But as soon as you are fit you'll never see that number again.

Another thing I noticed when being fit/peaking, riding tempo my HR seems to be very low to the point where I thought my HRM was malfunctioning but as soon as there is a hard effort I'll reach my max no problem, which rules out the malfunction theory.

Edited March 5, 2014 by milky4130

[Ken Prentis]

I have also noticed this during a racing season. After trial and error i have noticed this only happens to me if i am over training or need a rest... I am no expert and am not saying that this is the cause in your situation but maybe something to take into consideration. The way i see it the heart is a muscle like all others in the body and when its tired it will battle to operate at max effort.

[TALUS]

I am too lazy to check all my facts, so maybe just use my statements as a starting point for reading further. Heartrate is determined by many factors - one being pre-load (the amount of filling before contraction). As you get stronger and more efficient (skeletal muscle and cardiovascular) the preload increases. This means you pump more effectively at the same point of load. I doubt whether your absolute max would have decreased but you may reach the point where other factors such as muscle power/ lactate threshold/ central governor/ resperatory effeciency/ bleeding through the eyes etc. may be reached before your cardiac max and thus prevent you from reaching it. Warning: Double check everything I said - it has been a long time...

Edited March 5, 2014 by TALUS

[V12man]

I am too lazy to check all my facts, so maybe just use my statements as a starting point for reading further. Heartrate is determined by many factors - one being pre-load (the amount of filling before contraction). As you get stronger and more efficient (skeletal muscle and cardiovascular) the preload increases. This means you pump more effectively at the same point of load. I doubt whether your absolute max would have decreased but you may reach the point where other factors such as muscle power/ lactate threshold/ central governor/ resperatory effeciency/ bleeding through the eyes etc. may be reached before your cardiac max and thus prevent you from reaching it. Warning: Double check everything I said - it has been a long time...

 

Spot on... but to do a proper max HR test you need to be fresh and rested - 3 - 4 days off the bike resting seems to give the best results - you should see it pick up 10 - 15 bpm easily.

 

You will also notice on a multi day event that the max HR you achieved every day decreases a few bpm for every day you ride (assuming you are not managing your HR very carefully).... the heart also gets fatigued, just like legs... and it becomes more and more of an effort to drive the HR up high.

[rouxtjie]

Yip...the diesel effect. One of the reasons I dislike HR based training. Would rather go with perceived exertion.

[LongDonkey]

Exactly the same thing happened to me (also old....). Will look at resting for 4 days and see what happens as indicated above. Tx

[attiec]

@TALUS - Makes perfect sense and more or less what I expected, but I was just surprised that there is so little on this on all the sport science stuff out there.

@Rouxtjie - Been 'ignoring' my HRM for training for years. Being older, I only use it to indicate level of fitness, onset of illness, verifying my perceived effort and monitoring my old ticker for egine trouble. .

 

I am too lazy to check all my facts, so maybe just use my statements as a starting point for reading further. Heartrate is determined by many factors - one being pre-load (the amount of filling before contraction). As you get stronger and more efficient (skeletal muscle and cardiovascular) the preload increases. This means you pump more effectively at the same point of load. I doubt whether your absolute max would have decreased but you may reach the point where other factors such as muscle power/ lactate threshold/ central governor/ resperatory effeciency/ bleeding through the eyes etc. may be reached before your cardiac max and thus prevent you from reaching it. Warning: Double check everything I said - it has been a long time...

[mtbDobby]

I'm also no expert but what I found amazing during last years epic was in the 1st day or 2 my Avg was around 155bpm, by the end of the 8 days my avg was below 120bpm and I could not get it over 130bpm no matter how steep the climb.

 

This points to the fatigue mentioned previously and actually all posts above have valid points - rest a couple of days prior before testing max HR

[NotSoBigBen]

I'm also no expert but what I found amazing during last years epic was in the 1st day or 2 my Avg was around 155bpm, by the end of the 8 days my avg was below 120bpm and I could not get it over 130bpm no matter how steep the climb.

 

This points to the fatigue mentioned previously and actually all posts above have valid points - rest a couple of days prior before testing max HR

 

I had pretty much the same experience .... almost like the body's own 'governor'?

 

Edited March 6, 2014 by NotSoBigBen