Approximately 145. Interesting question does the performance reducing BPM number lower with age or are older folks inoculated against stress related performance decrease because of an inability to jack up their heart rate? Of course no one is going to get review board approval to test stress response in 75+ year olds. Be interesting to replicate limited BPM range with medication and see if performance still declines under stress.
This is an annoying read but discusses some studies of performance under stress. https://www.amazon.com/Combat-Psycho.../dp/0964920549
There is a lot of real research out there but as you note the internet is broken, I wouldn't bother looking without medical library access. And not just the military the evil soda merchants spend a lot of money researching this stuff as well. https://www.si.com/edge/2015/05/08/s...ormance-center
Us highspeed hardcore pro sailplane pilots are a sad lot compared to people that take human performance seriously.
On Wednesday, March 28, 2018 at 8:36:01 AM UTC-4, son_of_flubber wrote:
On Wednesday, March 28, 2018 at 7:09:06 AM UTC-4, wrote:
Mental and physical performance reduction does occur above a heart rate of @145 when that heart rate is stress induced.

I have a hard time believing that 145 bpm is a constant threshold across all ages and fitness levels. Does anyone know of a peer reviewed citation for that magic number? (Facebook and infowars.com do not count as legit 'research'.)

How many 75+ year old hearts can even beat at 145+ bpm? Does the 145 bpm rule make older glider pilots immune from stress induced skill degradation? I think not.