Low Watts with High Heart Rate

Hi All

I am doing Sweet Spot Base at present and on some of the workouts the wording at the bottom tells you that the workout will help your body use higher portions of fat as an energy source rather than carbohydrates, (can’t remember the exact workout).

I assume this is because the intensity (watts) isn’t super high so Trainer Road assumes my heart rate will also be pretty low. But my heart rate is actually right up at around 90% of my max (based on my peak ramp test heart rate) which means I would only be using carbohydrates.

So I can’t really work out whether I should just ignore the writing and continue with the sweet spot programs that are scheduled and ignore the writing or if there is an obvious contradiction and should look into this?
My goal at present is to set a good base and improve my base for next year where I have some century rides to complete.

Any thoughts or advice please?
I guess I am sort of asking whether heart rate or power output is more important to focus on when you have both factors available to you?

Thanks in advance

Day you did not mention the volume neither your cycling background. Anyway you shouldn’t worry too much about HR. Although I should say that it may indicate a poor aerobic base. I did my first round of structured training with TB low volume. And I’m now doing SS Low volume. I can say that if I got in directly with SS work I would have quit. The fist few weeks are the harder.

Also keep in mind that your HR is effected by a lot of factors, sleep, hydration, fuelling temperature, cooling. I just bought a fan and it makes a hure difference. Maybe as much as 10 beats per minutes.

Last thing your Ramp test HR is likely not your MAX hr. It’s probably a little higher. You may also be one of the people for whom ramp test isn’t the best.

But power is more important than HR. If you manage to complete the workouts at this intensity it’s likely your FTP is accurate.

Ignore the message. All intensities of endurance training increase your ability to burn more fat at a given power or pace.

Apologies for the slow reply. Was away this weekend.
My background is 2 years cycling although each year has been severely hampered (shoulder op the first year and a collision with a car this year meaning I lost the whole summer on cutches).
At present I am cycling 3 indoor sessions per week (1 over-under session for 90 mins, 1 sweet spot session of 60 mins and 1 sweet spot interval session of 90 mins). I also do an outside ride of 50-60 miles for endurance.

My query about heart rate against watts is that my endurance session outside today was around 90 mins in zone 3 and 90 mins in zone 4. This isn’t intentional, it’s just my heart rate hits 170bpm pretty easily. My basic understanding is that you grow more capillaries when you are working with oxygen so if your heart rate is too high, you body won’t do this and therefore won’t be able to start learning to use fat as a source of energy (instead relying on carbs).
If I have some long sportives to complete this year (about 4-5 century rides), is allowing my heart rate to go so high because I’m focusing on Trainer Road power targets going to help me with these long sportives?