Reply To: Heart Rate Drift Test showing high aerobic Threshold July 16, 2024 at 3:33 pm #135398 Brian BauerModerator do you have access to a treadmill? try running your drift test on one if possible. I don’t see 160-165 as high for a 30yo. my Aet is about 155 when I test at 6,000ft of altitude and I am 54.