A few years ago I was sitting in the backseat of a friend's car driving to Miami for a race. We were talking about everything we could think of (its a long drive from Orlando) including the normal training blah blah blah. At one point my friend was telling me about someone she knew who claimed to train "10 hours a day" while getting ready for an Ironman. My Response: "That's not training, that's touring."
To this day that one expression seems to ring a lot of bells in people's heads when I mention it. I hear about BIG training all the time (i.e. more hours than I train), but it has never been overly concerning to me. When I hear that someone is training a ridiculous number of hours I rest easy knowing that they are ultimately having to go "slow" to accomplish it. I can also bank on them most likely being exhausted on race day (when it actually counts). (And keep in mind that I train with a solid amount of volume; 27-30 hours when getting ready for IMs)
I think I can confidently say that many people hope that hard work will be rewarded fairly. Unfortunately working lots is not the same as working effectively. I always remember hearing people complain about how much they studied for a test, but ultimately scored poorly on the test. Clearly they put in their time observing the material, but perhaps they did not engage the material (and sometimes the test was just stupid hard).
Tying this back into triathlon and training hours is easy.
If I cannot train at an intensity that creates a training stimulus (steady and above) then I am doing nothing more than burning calories and making myself more tired. Do not confuse this with allocated easy training; i.e. recovery swims rides and runs. I am speaking in terms of easy training replacing quality training based on the justification that one's training volume is high therefore easy training is OK.
The next time you find yourself in a position where you are forced to go easy you should ask yourself this:
Is this the best session for me or my training log?
p.s. I'm finally over my illness and I am building my training towards Buffalo Springs at the end of this month.