Your heart can almost always beat faster than what is accepted as “max HR”. Still, the highest HR you can reach under a given set of conditions (fitness, temperature) is generally reproducible to within a couple of bpm, so we call it max HR.
As for HR vs. power, I think that power is a better indicator, as you will never underestimate the actual VO2 demand that way. OTOH, you can artificially jack up your HR without raising VO2 to the same degree - for example, just pedal abnormally fast.
People around here like to bandy about 90% of max HR as “good enough”, but I don’t think it is, at least for VO2max efforts. It equates to only about 85% of VO2max, which is only slightly above FTP for the average person.
Rather than assuming that VO2max corresponds to 120% of FTP in everyone then prescribing intervals of fixed duration only to see some/many fail, TR should have prescribed open-ended efforts at that intensity.
Almost everyone would be able to go long enough to make it a mostly aerobic effort, but few would last so long that they couldn’t get close to VO2max. People could then just pack it in when they couldn’t keep it up for at least, say, 2.5 minutes.
Isn’t this forgetting what VO2Max is i.e. maximum oxygen uptake?
One way improvements in VO2Max, i.e. getting more oxygen to the muscles, can be made is by training the muscle that pumps oxygenated blood to the rest of the body. As heart rate tracks close to VO2 we can use this for training. Working at 90-95% max heart rate is a good way to increase adaptations to stroke volume by improving the volume and wall thickness of the left ventricle.
Overall, VO2 tracks more closely with power than with HR.
ETA. Snagged this off of another forum. Note how VO2 decreases much more quickly that HR when exercise stops. Now multiply that lag during repeated efforts (intervals, hills) and toss in cardiac drift, and you should be able to see the point.
It is the power you generate that determines the demand for ATP, and hence the demand for O2. In turn, the demand for O2 is what drives the cardiovascular system. Thus, if you want to make sure that your VO2 is high enough to induce cardiovascular adaptations, make sure your power is high enough for long enough. It really is that simple.
Just elevating your HR is not enough, even in the context of exercise. For example, circuit weight training can result in HRs comparable to endurance exercise, but does not produce nearly as large of an increase in VO2max.
Note the HR response.
Note that VO2max increased by only 8%, versus the 15-25% increase normally found with endurance training.
ETA. Here’s an even better comparison. VO2max increased by 18% with endurance training, but only 11-12% with circuit training. Average HRs were 152 bpm in the cycle group and 134-143 in the circuit training groups, which is obviously too small to explain such a difference.
Of course, HR can also be elevated in response to non-exercise stimuli as well, e.g., mental or thermoregulatory stress. The latter in particular can result in very high HRs - all the way to maximum, in fact. Yet, repeated heat stress does not increase VO2max to the same extent as endurance training.
Pay attention to your power, and everything good will follow.
Regarding HRmax and VO2; my max HR outside is around 200, highest I’ve seen is 203 a few years ago. Inside, I’ve never been above 190. When I only get to 180 during my intervals, am I not pushing my self hard enough, or should I use different HRmax inside/outside?
doing 5 x 5 over the summer on my usual hill, I’ll average around 390w and usually see HR hit 156-58 at the end of the intervals. I rarely see anything over 160. FTP is in the 340 range.
doing 8 x 3 today on the trainer, fixed gear, 105rpm, 370w. HR would hit 150 after the first minute and then peak at 154-55. FTP is 330 right now.
not hard enough? or does accumulating time in zone also effective for stimulating adaptations? or is the answer…“well, it all depends…”?
This week i did 2 early morning rides (2x25’ @FTP power and 1x47 @ FTP power). I was fresh because I had a cold the week before and did only Z2 rides. Looking at my heart rate i had 16’ and 30’ above 172 (max is 182).
Are those vo2max workouts or threshold workouts?
*I think I know the answer but want other people’s perspective
Follow-up question on this: What would you say if somebody has crazy high HR indoor but way lower power than outdoor (averaging 10bpm more, 20w less indoor despite cool temperature and fan). Any theory why this might be the case (let’s assume no overheating)? If power is more important than HR then doing the VO2s outdoors would be better in this case?!
I find v02 max work so hard (yes I know supposed to be hard!). I can do 2x40 or 1x75 at 90% without much issue but yesterday really struggled with Givens+1 which is 2.5min intervals at 118%.
Let’s face it, 9 x 2.5 mins is at the very low end of time for v02 intervals but was really struggling and quit on last interval.
Therefore I guess the workout was a success but idea of 3 min intervals or longer seem impossible at moment!
I guess question is…will 2.5mins do the job (usually hit 95%max HR after around 60-75 secs after first 2 intervals) or do I need longer intervals but know might only manage say 4-5 intervals of 3 mins
I mentioned the below in another post, but you may need a slight adjustment in intensity for VO2 Workouts.
Regarding VO2 workouts, the percentages in the workout are guidelines/starting point. You are supposed to adjust VO2 workouts to ensure you are getting the correct stimulus. For instance, these are the instructions for my VO2 workout today:
“Important: Performing these intervals at 125% FTP assumes you can complete the intervals with few/no breaks. If you’re frequently skipping repeats or backpedaling during the brief floats, reduce the Workout Intensity to your repeatable aerobic power.”
Read this about trainers and wheel momentum, it starts with third paragraph:
I’ve got a Kickr direct-drive (wheel off) and can simulate low momentum ‘energy waster’ condition by shifting into small chainring and having a sloppy pedal stroke. That will drive my HR up every time.
Cheers for that - I guess my point was - am I better doing 2.5 min intervals at (say 115-118%) or 3 min intervals at (say) 110%. Idea of more than 3 min intervals at more than 110% is a no go at the moment (at least if I want to do more than 1-2 intervals!).
I can do 80 mins at 90% no issue and test FTP via a 40min test so happy FTP is realistic!
Another question regarding cadence. I mainly do 5x4min VO2max intervals in resistance mode on rollers. If I do them with a cadence of between 90-100RPM I can average around 120% of FTP. If I drop my cadence to between 55-60RPM I can easily hit 125%. HR is the same for both cadences. Should I do the intervals at a lower cadence and aim for a higher power, or should I try and get better at nailing the intervals with a higher cadence?
IIRC the coaching in the workout is to spin the higher cadence. In general, the TR coaching encourages a cadence of 85 rpm and above as this emphasizes aerobic work (which is more repeatable) than anaerobic.
