35 mins steady @ 93% MHR? How dangerous?

[csobel]

One of the guys on our team was doing a rescue on the mt. and had a polar on... HR >90% for close to 6 hours. This is in a very well conditioned operator, but it goes to show.

 

[pintoca]

One of the guys on our team was doing a rescue on the mt. and had a polar on... HR >90% for close to 6 hours. This is in a very well conditioned operator, but it goes to show.

I'm pretty sure oxygen rate would play a role here as well, how high was this mountain?

 

[csobel]

Around 9-10k about 1200 feet from the summit most of the time.