Training & Nutrition - Training with a HRM, not sure what to make of recent indoor TT

Ok, so when I first got my HRM, the first thing I did was what Friel suggests. A good warmup, then a 30 minute time trial like effort on my trainer at home and record my heart rate for the last 20 minutes of it. I did that back in the fall and my average heart rate came out to 168. My max was 183. I then based all of my training zones off of that and begun my winter training.

Fast forward to 3 weeks ago. I do an indoor TT. Did a nice warmup like before, get ready to start, have my HRM start recording and go. 23 minutes and 29 seconds later, I finished and come up with an average heart rate of 184 and 193 for a max. I think its just a fluke and I don't adjust my training zones

Fast forward to yesterday. I do another indoor TT. 22 minutes of suffering like before and my average heart rate now comes out to 187 with a max of 195.

Is it time to adjust my training zones? Also, does anyone have any clue as to why this would have happened?

Ok, so when I first got my HRM, the first thing I did was what Friel suggests. A good warmup, then a 30 minute time trial like effort on my trainer at home and record my heart rate for the last 20 minutes of it. I did that back in the fall and my average heart rate came out to 168. My max was 183. I then based all of my training zones off of that and begun my winter training.

Fast forward to 3 weeks ago. I do an indoor TT. Did a nice warmup like before, get ready to start, have my HRM start recording and go. 23 minutes and 29 seconds later, I finished and come up with an average heart rate of 184 and 193 for a max. I think its just a fluke and I don't adjust my training zones

Fast forward to yesterday. I do another indoor TT. 22 minutes of suffering like before and my average heart rate now comes out to 187 with a max of 195.

Is it time to adjust my training zones? Also, does anyone have any clue as to why this would have happened?
How much had you been riding when you did your first test? It could be simply that your legs weren't strong enough to stress your heart and that over the winter your legs are no longer limiting your longer efforts.

You don't say how you are testing your MaxHR. You won't get a meaningful MaxHR during a normal TT effort used to determine your LTHR. Also, your MaxHR will likely increase for a while as your legs get stronger (at least mine did).

Sounds to me like your LTHR is in the neighborhood of 184 to 187. You will see variation depending on your motivation, temperature, level of fatigue etc. In other words there are lots of factors that can affect your HR during a given test.

If you are following Friel's basic training plan you might try doing your tests monthly at the end of an R&R week so you are well rested. Ultimately your LTHR shouldn't be changing much but the power you output should slowly increase.

Ok, so when I first got my HRM, the first thing I did was what Friel suggests. A good warmup, then a 30 minute time trial like effort on my trainer at home and record my heart rate for the last 20 minutes of it. I did that back in the fall and my average heart rate came out to 168. My max was 183. I then based all of my training zones off of that and begun my winter training.

Fast forward to 3 weeks ago. I do an indoor TT. Did a nice warmup like before, get ready to start, have my HRM start recording and go. 23 minutes and 29 seconds later, I finished and come up with an average heart rate of 184 and 193 for a max. I think its just a fluke and I don't adjust my training zones

Fast forward to yesterday. I do another indoor TT. 22 minutes of suffering like before and my average heart rate now comes out to 187 with a max of 195.

Is it time to adjust my training zones? Also, does anyone have any clue as to why this would have happened?

What was your distance & pace for the first? Were you at your max sustained effort? What the second TT the exact same course? Did you put in comparable efforts? If so then you have comparable results and a more accurate LTHR.

My 20 min test last year gave me a HR of 168. I've noticed that in races (mostly crits) my HR tends to average around 167-169 (over 15 races last season). This winter, I am quite comfy above 170 for long durations, and I have since slightly adjusted my training zones because I believe this 2-3 bpm difference is more accurate. I think you should too.