# Calculating LT1 and LT2 approximately without a blood test? **URL:** \ **Category:** Training\ **Tags:** polarized\ **Created:** [March 15, 2021, 8:57pm UTC](https://www.trainerroad.com/forum/t/calculating-lt1-and-lt2-approximately-without-a-blood-test/55533 "2021-03-15T20:57:15Z")\ **Posts on this page:** 1\ **Showing post:** 725
**Author:** ![tshortt](https://sea2.discourse-cdn.com/trainerroad/forum/user_avatar/www.trainerroad.com/tshortt/32/3100_2.png) [@tshortt](https://www.trainerroad.com/forum/u/tshortt)\ **Post date:** [March 17, 2022, 10:00am UTC](https://www.trainerroad.com/forum/t/calculating-lt1-and-lt2-approximately-without-a-blood-test/55533/725 "2022-03-17T10:00:07Z")
> [@Anyone using HRV? (Heart Rate Variability)](https://www.trainerroad.com/forum/t/anyone-using-hrv-heart-rate-variability/5664/270): > > Estimating aerobic threshold using @marco_alt HRV Logger has been briefly discussed on the Iñigo San Millán training model thread. It is somewhat relevant there as ISM’s “Zone 2” seems to fall right at LT1. However, a deeper dive into this subject seems to belong here. After some initial confusion on my part, I managed to conduct a little ramp test today to see where .75 DFA/alpha 1 fell. I based the protocol on @BJRMD blog, etc, 6 min steps where you throw out the first reading at 2 mins, achi… Ok. Sounds different than what Marco and Bruce recommended in the above thread. 6 min stages, establishing steady state. Maybe that’s changed and if so, cool. It has been over a year it was early back then. As you can see, I found good agreement. After experimenting with day to day usage, I moved on and hadn’t thought about it much until it came up again in this thread (due to Marco tweet). --- _[View the full topic](https://www.trainerroad.com/forum/t/calculating-lt1-and-lt2-approximately-without-a-blood-test/55533)._