I’m a 27 year old male with a 10+ year history of frequent ski touring during winter combined with cycling and mountain running during the summer; before that I swam and played water polo competetively. During winter in particular, it had not be unusual to have 3 or more 6-8+ hour days of ski touring per week. Given that, I expected to have a reasonable aerobic base, but given the prevalance of ADS, I am extra wary and don’t want to make assumptions.
I followed the protocol for the indoor AeT and found my AeT to be appx 157 BPM given at that rate given I could no longer sustain nose breathing with a moderately deep but consisent respiratory rate. I felt confident with the results. I set Z1 as <142, Z2 143 – 157, Z3 158+ with a plan to perform the AnT protocol soon.
Later that week, I went for a run after work and in the first 4 miles gained about 800 ft elevation with an average HR of 146 and speed of 6.5mph. I felt pretty sluggish and had a difficult time maintaining nose breathing at this rate. On the last 4 miles, average HR was 144, speed was 6.8 mph. I felt better and could sustain nose breathing.
My questions are these:
Is it possible that I overestimated my AeT or conducted the test poorly?
Is this fatigue simply accountable to a poor warm-up or the elevation gain in the first half of the run?
Or are there other factors which I am missing?