I am wanting to do an 20 minute FTP test, have done them multiple times in the past - always in the evening. However, I'm just curious if anyone has any insight on this. What I'm trying to decide is whether you get a more accurate test result in the morning, or in the evening. I don't have a power meter, but I'll be using trainerroad virtual power to complete the test. So when I ride outside, which is most of the time, I use heart rate. Based on the test results, I calculate my heart rate zones. However, I've noticed that effort in the morning seems to be not as good as efforts I can give out during the evening. Also, my heart rate for that effort seems different in the evening, usually higher "per" RPE... if that makes sense. So I guess what I'm trying to get at is, I feel like depending on what time of the day I do my testing, my heart rate zones will be different! Does anyone have any suggestions? I'm thinking do the testing later during the day. My only concern is the heart rate zones will be too high for training in the morning. After so many years of training, I can't believe I'm just now thinking about this.

I'm not getting how you'll be training with HR if you don't have a HR monitor.

Do the test as near as possible to the time of day you'll normally be training if you think it makes a difference.

Erg.. I meant I don't have a power meter. :-/ mondays.

A morning FTP test will be more accurate measuring your morning FTP. An evening FTP test will be more accurate measuring your evening FTP.

I say knock off work early and take the test at noon.

My HR is significantly higher for a given power level in the morning than evening. I commute and ride with power so I have tons of data. Perhaps because of the times when I ride (morning rides start between 6:30 and 7am) but my morning power is normally lower than in the evening. It doesn't seem to have an effect when I start at 9am for a group ride.

If you're training mostly in the evening or afternoon I would use the evening test for your HR zones. It's not going to make that much of a difference and you should also be calibrating by RPE if you don't have a powermeter. RPE is probably better than HR for determining how hard to ride.

Thanks everyone. I did the test this morning fyi. At least it's done now :-)