I am 54yr. racing/riding (mostly) for 37yrs. I have begun to train implementing a Polarized approach where I ride long low intensity rides to build my aerobic base. For this intensity I measure by HR vs. Power. My Max HR is somewhere 183-186bpm and I maintain a range of 125-135 for these rides of 3-5 hrs. I certainly believe that they do build a deep aerobic base from which I add progressive intensity as competition draws near. I also include short higher efforts within these rides as well 2-3 x 10min. at tempo-- sweet spot but always finish final 30-60 min. at low to fatigue.
My experience is that the more I train at the low intensity the lower my Max HR becomes. I believe my TH HR is 169-173 but I had periods where I couldnât even attain that at full effort. In other words my Max HR wasnât even as high as my TH HR when I was including this LSD within my training regimen . When I started to exchange LSD volume for intensity my HR began to increase. Now in the off season break I can again reach my more normal Max HR in 182-185 range but this is only now with 2+ weeks with only one ride/ wk.
Why does my Max HR decrease with the inclusion of the LSD?
At this age I ride no more than 4 days/wk resting the others and my total âPie of energyâ is fairly fixed so if I ride longer I have to do less intensity elsewhere.
I donât know about LSD training specifically, but I usually find a similar pattern from increasing training volume and fitness. I like to think its down to improved efficiency but I guess fatigue could also be a factor.
As an example I did 3 zwift ramp tests to benchmark fitness over the past year and max HR declined as power and fitness increased.
After a break and just before starting base training 27th Oct 2020
1 min peak 360W/183bpm
max 185bpm
After base training 22nd Jan
1 min peak 388W/176bpm
max 177bpm
After 9 week pre-season block 29th March
1 min peak 405W/175bpm
max 176bpm
If I understand your post correctly, you noticed a drop in HRmax since you started with LSD, and HRmax is back to ânormalâ in the off-season. You also noticed that you could not maintain your known TH HR at some point in the season when giving it your all.
In that case the root cause is fatigue:
Your cardiovasculair system requires more time to fully recover in between sessions, or your your muscle glycogen level is insufficient to maintain the power long enough to get your HR to itâs max.
Take more rest, or improve fuelling. Testing these two options will tell you which it is.
I understand that fatigue can be a factor, but with so many variables affecting heart rate can we really say for sure that is the only explanantion?
Could positive training adaptations not also result in a lower HR? If you have increased stroke volume/cardiac output and improved peripheral efficiencies from training then surely the heart doesnât need to beat as fast to meet the same demand from the muscles? I guess for me, I would tend to look at the power to heart rate ratio and if that is improving then training is generally going in the right direction.
Thank you both for your thoughts. While I am aware and have too often experienced the affects of fatigue on HR I donât believe (yet) that was the reason for me here.
My experience is simply an inverse relationship between Max HR and LSD component of weekly workout. This progressed over 3-4 months and was consistently present. Also my resting HR as well as Heart Rate Variability (per Whoop) was utilized to determine training, intensity and rest. I try to rest as diligently as I train.
My power output did increase relative to a specific HR as did my duration at higher intensities so there was clear aerobic improvement but a suppression of ability to reach highest intensities reached previously along with Max HR. This reversed with higher volume of intensity and diminished LSD but the aerobic benefit of the LSD was realized just couldnât keep both at same time.
@Aberardo Iâm no physiologist but it sounds to me like your training is working well. A solid aerobic base base topped off with some intensity that brings everything up.
It would be great if someone with a better grasp of the physiology is able to provide an explanation of the lowered HRmax, but intuitvely, I would expect to lack a bit of top-end after a lot of LSD training.
There is also the question of whether middle aged athletes might actually benefit from lower volume whilst maintaining a bit of intensity? Iâm also 50+ and have recently read The Midlife Cyclist by Phil Cavell which is a great book on the how and why of adjusting training as you get older.
As the review from commentator Carlton Kirby says âPhilâs book can help you be as good today as you always said you wereâ
