Originally Posted by bdcheung
two immediate reasons:
1) If I'm riding at my FTP and my HR is peaked, I know it's time for a day off.
2) I like data.
1) That decision should be based on whether you can do the watts or not. Introducing HR just introduces HR's problems. Most people would continue their workout unless they couldn't produce the power. In Allen's book, there's a table that provides guidelines as to when to call it quits.
2) More data is not necessarily better.