For those of you doing a lot of Zone 2, what is your typical IF?
Endurance IF
- .71-.75
- .66-.70
- .61-.65
- .60 or less
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voters
For me its around .7 for a 1 hour midweek ride and .65 to .67 for my long weekend zone 2 rides
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Depends 
if it’s a 6+ hr ride it will be like .5 especially when doing higher intensity rides around it.
Other times it can go up closer to .8 for a shorter ride.
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0.64 if I behave myself.
0.80+ if I hit some sprints.
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Depends. Average around .6 for 2-5 hour rides. Over .7 for significant amounts of time and consecutive days and you can cook yourself pretty quickly.
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I try to push the upper end of Z2, which for me is 75-76% FTP as best I can tell based on ventilation (eg carry on a conversation) and HR decoupling. I feel like riding 70-75% FTP for Z2 rides pushes my endurance. Will see as the season progresses, though, since I’m experimenting with 10-12 weeks of offseason (which included a lot of Z2), TB II, TB III, GB I-III, then build and specialty.
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Interesting…
This is actually what prompted me to ask about Z2 IF.
I end up doing almost all my Z2 at around .68-.71, even for 4+ hour rides. Lately I have been wondering if I need to try to do more at around .75, or conversely, if I should be backing down to an easier pace. Wanted to see how other TR users were handling their Z2 volume.
I do around 10-15 hours per week, with about 3-4 hour of that time doing higher intensity. I’ve been on a plateau for a while, and I’m not sure if I need to ease off the Z2 and hit the intervals harder, or bring that Z2 up.
Thanks to everyone who’s taking the poll!
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I’m a firm believer in making your easy rides easy and your hard rides hard. I’ve burnt myself out before trying to make easy rides harder and it’s just led to not being able to complete the hard rides. Obviously, ymmv, just sharing the view from the other side.
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I typically let my legs self-select power on endurance days. If really fatigued, that might be close to .6 IF. More typically, it’s .7IF or higher. Whatever feels easy for the legs. Also depends on inside or outside. With crappy weather this winter, I’ve been doing a lot of indoor stuff. That always translates to higher IF since there is no coasting and I just kind of zone out at a comfortable steady pace while watching a movie or listening to a podcast.
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Same here. That’s why I’m taking a prolonged base season. I have to be mentally ok with doing what @grwoolf describes below.
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Looking. at last couple of weeks for my longer Z2 outings, 3 hours overall 0.61, and 5 hours overall 0.67.
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I think a good general rule of thumb is “Stay in Z2”. If you are feeling good, go higher in Z2. If you legs are feeling tired or you have other stuff going on, aim for lower.
There is a trend right now to overthink what Z2 is, IMO…if you adhere to the above, you’ll be good to go.
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I have no idea. I’m just out doing easy riding at a comfortable pace.
Power numbers have no meaning for those rides.
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I am riding by HR cap (~80% of LTHR), which is around IF 0.6 - 0.65, depending on temperature/humidity, etc.
This is intensity I know I can do for months 24-30 hours/week without burning out.
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How long did it take until you could do 24-30 hours of that before your legs stopped getting sore, or do you still end up taking rest days / weeks?
Good point about HR. While I tend to ride toward the upper end of Z2 when I have power, I go by equivalent HR when on a spin bike without reliable power (eg when traveling). When healthy I know my “upper Z2” HR is 133-143 bpm. I’ll keep it in this range when on a spin bike, but is largely affected by room temp and (lack of) cooling / fan. I don’t know what power it would equate to but, if I had to guess, it would be 60-68% FTP.
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A good way to look at it is considering kj burned. As long as you stay sub lt1 it’s a very good metric to pay attention to.
You don’t have to go much longer to get the same kj burn for a noticeable drop in power.
My weekday endurance rides are generally easier/recovery either from the days prior interval workout (Tuesday/Thursday) or from the weekend long ride. They’re usually 1-2 hours and around .58-.63 IF.
My long weekend Z2 rides (3.5-5 hrs) are usually around .65-.7 IF. Strong believer of keeping my hard days very hard and my easy days pretty easy. My long weekend ride does wear on me a bit as I work on my durability.
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This is a really good read with regards to zone 2 intensity.
TLDR: Below 60% Vo2Max, heart rate is dominated by parasympathetic activity. From 60-66% Vo2Max sympathetic system is activated to a low degree. Above 66% vo2max, the sympathetic system is dominant.
Looking back at my tests, 60% vo2max was around 1.1-1.3 mmol, and roughly 0.6 IF based on blood lactate testing / long form FTP test (40’ all out). My VT1 (2 mmol) was around 75-80% vo2max depending on the test day (roughly 80% max heart rate, or .75-.8 IF), so well above 60% vo2max and even above most models of common zone 2 max power.
I guess my take-away is that there is probably a lot of benefit for doing some endurance work at .6 IF or below just to improve vagal tone (which we lose as we age), with a max of .65 IF for doing heavy volume without any major negative nervous system disturbances or stress. .66-.75 IF is probably good for improving muscular endurance and durability and improving lactate clearance / shifting LT1 to the right, but it comes with a lot of added stress to your system. Even though the definition of “zone 2” (or zone 1 on a 3 zone model) is up to 2 mmol blood lactate, I think that trying to push at the top of zone 2 for all of your endurance work without balancing it out with work well below .65 IF is probably the wrong approach.
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When doing z2 rides, I use both power and hr to determine what I’m doing. I probably shoot for between .58 - .65 IF, however, I will make sure my hr is within a certain range. If my hr is. getting high, I ease off.
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