Best Metric to Measure LISS Ride

Hi All

I signed up for Le Etape in July 2020 so am in my base phase training right now.

For my base, I do three indoor workouts a week using Trainer Road (just started Sweet Spot volume 2) and one long outdoor ride at the weekend of between 3-4 hours.

Indoor training is measured in power. However, I am unsure whether I should use power or heart rate for the long steady state ride at the weekends. My heart rate tends to sit high (155-170bpm) if don’t deliberately try to keep it down which, with an approximate max of 192bpm (based on the ramp test and the highest I’ve seen my heart rate on a big effort outside), puts me right up at around 80-85% of my theoretical max.
I do get fatigued on longer rides (60miles+) so my thinking was to keep my heart rate on zone 2 in order to get an aerobic adaption over winter. But I have been told to forget about heart rate and just look at power.
I’m no physiologist but I don’t understand how allowing my average heart rate to be so high on every ride will allow me to develop an aerobic base (more an anaerobic tolerance surely?).

If anyone more knowledgable than me can tell me whether my outdoor ride would be better served focusing on keeping heart rate in zone 2 (145bpm or less) or just ignoring heart rate and going off of power that would be greatly appreciated.

Extra info:
2.5 years cycling experience
Trains 7 hours per week approx
Has power meter on outside bike

Thanks in advance


Power, hands down. Check your time in zones at the end of each ride to confirm the volume you are getting in Z2, you could be doing more Z3 and Z1 than you think.

Check out this forum thread