deepakvrao

My wife has often being complaining of an odd problem.

When she does intervals on flats/trainer, she can get her HR up to zone 5, and sustain for the duration of the interval. However, when doing hill repeats, even when power is above FTP levels, her HR often does not go into zone 5. Cadence is maintained at 80-90 or so on the hills too, and maybe 90-95 on the flats. Don't know how to explain this, but while she can maintain the power and cadence, the HR does not go above Z4.

Completely perplexed with this. Any ideas?

gregf83 

It's not unusual for HR to be higher indoors due to higher temperatures. You need a very large or a couple of large fans to simulate the cooling you get outdoors.

How did she determine her HR zones. If they are based on a HR measured while riding indoors they may not be set properly for riding outdoors.

deepakvrao

She got her HR zones by Joe Friels chart in his book, and the LTHR test was done on road.

chasm54

Why is this a problem?

The only thing that occurs to me is that on the hills she is hitting it too hard, so that her HR is lagging behind the effort she is making and she's blowing up before the HR gets up there. Try backing off a bit and giving the HR time to catch up. But as I say, it isn't clear to me why this is a problem.

Wesley36

+1. Higher power output and lower heart rate, if not an artifact of the fact that HR responds more slowly than power, is a sign of increased fitness.

deepakvrao

Thanks guys.

However, if she is fitter, then she should be able to put out even more power at a higher HR. SHe does not seem to be able to go into zone 5 at all.

This might be the answer.

Wesley36

Just to clarify, when you say "power", are you using speed on climbs as a proxy for power, or are you actually using a power meter? Because if you can use a power meter, just ignore HR, the power zone is more meaningful.

deepakvrao

^^Powertap.

gregf83 

If she were going too hard at the start that would be obvious from the power files. How long are the hills?

The other explanation is that her fitness is just improving. My FTP is somewhere between 285-300W and my threshold HR is around 167. I can do a 5 min interval at 340W and my HR won't go above 167 which is Z4. If I do the interval at 360 my HR will go to 170 which is maybe Z5.

My recommendation would be to throw away the HR monitor for a while and just use power. HR is not helpful for short intervals.

Carbonfiberboy 

Yes. He doesn't say how long a "hill" is. The fitter I get, the long it takes to bring up the HR. When I'm quite fit, I won't be able to get into Z5 until at least 15 minutes of climbing, sometimes more before I can attack effectively. If one is interested, one can climb for 15-20 minutes in Z4, then get up and attack at high cadence. That'll usually do it, if that's what you want to get to be able to do. After the attack, try to recover in Z4. If one learns to do this, one can attack repeatedly and sometimes wear down the other folks before you wear down yourself. Or the opposite . Fun, anyway.

Wesley36

Awesome, rather than having to guess, you have good hard data. If your wife is blowing up, you will see her power drop off. If she can sustain her wattage and her heart rate drops, then she has become more fit.

Beyond that, there is some value to keeping track of heart rate, but in terms of gauging intensity and using training zones, power is far superior to heart rate. Part of the reason is that HR responds to stimuli that has nothing to do with intensity - heat will effect HR, being buzzed by a car will cause HR to soar, etc. Another part of the reason is that HR lags behind power by as much as two minutes, meaning it is a poor means of gauging intensity. Power responds instantly, and precisely.

Luckily, determining your power zones is very much the same as determining your HR zones. While there are variations, HR and power zones use some version of `threshold`as the basis for setting zones, and this is the maximum intensity that a person can sustain for 1 hour - a 40k time trial can be a good proxy, since it takes about an hour for most people. Friel recommends a 30min TT to determine LTHR, simply because people are more likely to test frequently if it is a 30min TT - a 1 hour TT imposes a great deal of training stress. In either case, do the TT, and use your average power as your FTP (functional threshold power), and use this to set your training zones. If you can use power training zones, then this should be your primary gauge of intensity, not HR.

However, HR still can be useful. If you do not already use a program like WKO+ or Golden Cheetah, I strongly suggest doing so - I use GC because it is free. When you set up your profile you can enter in your threshold power and HR, and it will calculate your zones for you, and analyze your rides in terms of these zones (more sophisticated users can adjust these zones for different zone systems). Starting out with, what is most interesting is that the introductory screen for a ride will break down for you how much time you spent in each power and HR zone, both as a percentage of the ride and in minutes, and it will also calculate aerobic de-coupling as a percentage (see https://www.endurancecorner.com/decoupling). Very useful in analyzing the ride and evaluating fitness.