Expert: Todd Bublitz, RCEP - 7/10/2005

Question
    I'm almost 42 years old (9-63), 5'8", 152-156 lbs. and <10% body fat. My resting HR is 42. I cycle 8-16 hours a week, and incorporate lactate threshold intervals, sustained hill climbs, and moderate intensity, long mile days. My max heart rate is 183 bpm. To the best of my knowledge, from conducting multiple road tests, my lactate threshold is about 165bpm. Until a few weeks ago, I had been doing some LT training days, holding my heart rate at 165 for 30 minutes, and also have recently done some 30-45 minute steep climbs, holding steady at 165. I was under the impression, that I wouldn't be able to sustain anything higher for any substantial length of time without "blowing up". However, (and here is where my questions comes in) a few days ago, I was doing a group ride and after over an hour of riding, involving some sprints that I maxed out on, actually hitting 183 for the first time other than when trying to hit my max, I had a mechanical problem, and the group didn't wait. I tried to catch them for 40 minutes. I was able to maintain a very high power output, and held my heart rate between 173 and 178 for the whole 40 minutes. By my calculations, I averaged over 95% of my max heart rate for 40 minutes. Here are my questions about this.
1. Is my previous estimate of my LT wrong? Or was I just operating above my LT for that long?
2. Is this actually a good thing for me to do to increase my LT, and improve my abilities?
3. Can this be dangerous to push this hard?  

Answer
Bill,

Lactate threshold can be tested in a clinical lab or "in the field".  The lab test, with blood draws, should be more accurate, but you can't beat the "how do you feel on the road" test.  It all comes down to "how you feel".

The best answer to your first two questions is that you probably have increased your LT - if your LT test was done several months ago.  If you recently did a LT, then you may have underestimated your LT.

Of course it's good to increase your LT.  Most of your training gains will be due to increasing your LT.

Here is a pretty good article on road racing, training and LT.
http://www.velonews.com/train/articles/8217.0.html

"Can this be dangerous to push this hard?"
Theoretically, any increase in effort can increase risk of "injury".  The increase in risk could be 10% or 0.0001% depending on who you are.  For the average healthy person, the body will signal when you are pushing too hard - you just don't feel good - and the risk is very, very low.  Listen to your body.

You've probably heard this - Lance Armstrong spends significant time during races at 90-95% of his maximum heart rate.  Bill, you have to weigh your goals against your comfortable level of training, racing and risk.

I hope this helps.

Best wishes.

Todd