@Valentijn I don't understand this. This thread has people saying that multiplying by .6 is for healthy people and we should use 40-50%. When I plug in my numbers @ 50% (which may actually still be too high), it shows AT to be 85 (I'm 57 yrs old).
What do you mean by "85 is too low to use as a limit"? Don't we want the 'real' limit?
The 60% is not for healthy people. It's very, very rough estimate of AT for PWME. The estimated AT for healthy people is 80% of max HR. The thing is that most of us need to stay well below our AT
for routine activities and only go up to the AT for brief and exceptional circumstances.
So if you are setting your alarm at your AT only to know when you have to quit whatever you are doing immediately, then you want to set it at around the 60% max HR. If you are trying to gauge where you should stay for routine activities, then the 50% number is probably better. I'm guessing that is what Val is saying -- that 50% may be too low as at top end, stop-and-sit-immediately limit. But it might be fine as a place to stay for routine activity.
Another thing we all need to keep in mind is that tachycardia may screw up all these calculations. For example, if you have untreated tachy, you might not be able to get your HR down to 85 bpm for any activity. I know I couldn't prior to OI treatment. If I was standing my HR was over 90 bpm.
Let's keep this all in perspective, if we can. Any calculated, rule-of-thumb-based estimate of appropriate HR for various levels of activity/exercise is a very, very, very rough estimate and could be completely wrong for any individual. We PWME know our bodies are not behaving normally, or even exactly like that of other PWME, so an estimate that works for one person could be way off for another. The only reason we use the calculated AT is because it's better than nothing as a way to make a ballpark estimate of how not to constantly PEM ourselves. Since many of us can't (for various reasons) afford to do the 2-day CPET to get more accurate data about our own bodies, our choice is the very rough estimate or nothing.
If I had to use the calculated AT, I'd consider it a ballpark estimate to start with. If I still PEMed at that HR, I'd go lower until I had it set at a level where I didn't PEM myself. I certainly wouldn't consider it a set in stone, 100% safe HR limit.