Originally Posted by
garethzbarker
One time, I was mountain biking right after I started biking and I pushed myself so hard my vision blurred and I almost puked.
That's a good sign you hit your MHR.
For some history on age related MHR formulas and their weaknesses see:
http://www.nytimes.com/2001/04/24/he...ea9017&ei=5070 (you may have to register with the NYT to read, but it's free & worth it).