[Seth Keena]

Hi Karen,

Thanks for writing in. Happy to hear you’re gleaning training tidbits from the ‘cast and progressing your training. To your questions:

1) Seems plausible 143bpm is AeT/top of Z2. Whenever you have the time and the legs feel relatively fresh do another test this time targeting 143bpm near the end of the warm-up period. Treadmill based AeT tests are free and having more data will be helpful for you at this point.

2) It is very unlikely so. What’s going on is you don’t fit the formula as neatly as others and have higher AnT and max HR values than the formula predicts. Those formula are based on a bell-curve like data set but heart physiology can differ enough between individuals that you may not fit the formula exactly. Max HR is relatively easy to determine (basically, start by running fairly hard then increase effort every ~2min until you are forced to stop) but you don’t need to do one necessarily. Keep your threshold data simple and use the results of the tests as you have done them.

Likely you’ve improved movement economy and metabolic tolerance for hard efforts by way of training! For better or worse, most beginner and intermediate athletes find their hard effort performance the quickest to improve with the practice of training. The development of aerobic capacity tends to be slower. Signaling response and the associated metabolic support for hard efforts seem to positively adapt to stimuli quickly for most (not all.) Small movement efficiencies reduce the cost of moving as well. This is why intensity training is so fun! Like all adaptations, diminishing returns will eventually come, and interestingly it’s often the humble aerobic system that need growing to move the upper end level once again.

Hope this helps.

Seth