HR Tss? as opposed to power Tss

I have just started the sweetpot 18 week plan. The thing i am unsure of is i am using HR Tss because i do not have a power meter but i have noticed that when i convert a workout in Training peaks from power to threshold heart rate. It drops the tss for that workout. For example endurance zone two 1hour 30 mins is 75 tss but when i change it to threshold HR it becomes 58 Tss. so should i be aiming for 58 or 75. I know more is usually better. But am i doing enough if i only hit the 58. I have just done the said workout at a reasonable pace and got a tss score of 67.

Many thanks in advance Phil

Hey Phil!

Did you do the FTP test at the beginning of the SS plan and use the ‘FasCat Zones Worksheet’ found in the field test workout to set your HR zones?

Heart rate does have more variables that impact it than does power, so your actual threshold HR may be lower than when you tested. So for example if you were fatigued when you did your FTP test that could cause your HR zones to be lower than they should be.
If you have a lot of training under your belt, I would advise that you go back on other workouts, group rides or races were you put out a hard effort for an hour. See what your peak 1 hour HR was and compare that to your current heart rate threshold. From there you could lower your heart rate FTP a bit to match up with perceived exertion.

this same thing is happening to me and I did do the field test to set accurate HR zones

Hi Lacey
Thank you for your reply, but i think you may have misunderstood my question. Yes i have done the field test and set my zones correctly. The problem is that when i change a workout in training peak from power based to heart rate, No matter what my zones are set to Eg 151 or 181 threshold the prescribed amount of tss changes for example if the prescribed amount is 46 tss changing from power to heart rate changes it to 38 no matter what my zones are set at. I hope i have explained this clearly, and would like to know if i should be aimimg for the original tss or the altered tss.
Many thanks Phil

In the long run (at the end of your plan & beyond) Phil it won’t matter. Simply follow the plan by zones and duration and let your hrTSS be what is.

Your plans zones and durations determines hrTSS and if you are FtFP’ing then the hrTSS will be correct. I am going to guess they will be between your example of 58-75.

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Hi Frank
Thats great, Thanks for the reply

Regards Phil