Training & Nutrition - 98% of LT for 3 hours?

Help me make sense of this...

My best estimate of LT heart rate is 171 (max HR is 191, 46 years old). Today I went on a 3 hour ride with a lot of climbing with a much stronger rider, knowing it would be a very hard workout. I turn my HR monitor around on rides like that just to keep from getting freaked out when I see the numbers half way up a hill.

I get back home and it shows an average HR of 167, max of 190, and min of 125. It has always been accurate, and this was indeed a very hard ride. But averaging 98% of LT for 3 hours? I did not think that was possible. I have not been training long enough for my LT to be any higher than it is in terms of percent of max HR, and I am fairly confident that LT is right at 171 or so.

So is it fairly common to maintain such a high % of LT for rides like that? I'm still figuring some of this stuff out, but until today I did not think you could do such a thing.

Help me make sense of this...

My best estimate of LT heart rate is 171 (max HR is 191, 46 years old). Today I went on a 3 hour ride with a lot of climbing with a much stronger rider, knowing it would be a very hard workout. I turn my HR monitor around on rides like that just to keep from getting freaked out when I see the numbers half way up a hill.

I get back home and it shows an average HR of 167, max of 190, and min of 125. It has always been accurate, and this was indeed a very hard ride. But averaging 98% of LT for 3 hours? I did not think that was possible. I have not been training long enough for my LT to be any higher than it is in terms of percent of max HR, and I am fairly confident that LT is right at 171 or so.

So is it fairly common to maintain such a high % of LT for rides like that? I'm still figuring some of this stuff out, but until today I did not think you could do such a thing.

It depends how you define "LT". One definition I have seen describes it as an intensity that could be sustained for ~3 hrs. You are only estimating, afterall. How did come up with 171 bpm as your "LTHR"?

It gets easier to approach higher heart rates, thus a higher average HR the longer the ride (to a point) due to dehydration and your body shunting blood to your skin to keep you from overheating.

If you were to use power instead of heart rate, you'd probably find what you would expect.

lactate threshold where you are at the limit. you can ride below this level indefinitely.

so yeah 98% 3 hours or 20 hours, doesn't matter. lactate threshold is absolute. go above it and you
will need to stop or slow down soon. stay at it or below you can motor forever. your LT varies somewhat during a workout, and during the day, and over weeks and months.

I have similar results, 47 yo with a max hr of 193. I've found that I can sustain 170 or below for quite some time. But bump up past that a couple times, and it really runs you down pretty quickly.

That's the main thing I use the HR monitor for... on long climbs to make sure I don't blow up too soon. (And to keep my HR down on recovery rides. I tend to go way too hard on RR without the HRM)

Az

lactate threshold where you are at the limit. you can ride below this level indefinitely.

so yeah 98% 3 hours or 20 hours, doesn't matter. lactate threshold is absolute. go above it and you
will need to stop or slow down soon. stay at it or below you can motor forever.

This is wrong.

Everyone has a unique power/duration curve. I can ride for 90' at 95% of my max 1 hr power. For 3hrs, the power drops off to ~85%. For 6 hrs, it drops off to around 75%.

True, if I go above 100% of my maximum 1 hr power, the curve steepens a bit faster: I can hold 105% for only ~20', 110% for ~10', 120% for ~5', etc.

As the fuzz points out, little variations in these numbers make a big difference. It could be that your MHR is higher than you think. MHR is very difficult to achieve. It's also very possible that you are underestimating your LTHR. From your figures, I would estimate it as closer to 175. You averaged 87% of your reported MHR. I averaged 85% of mine on a 3 hour ride 2 weeks ago. I was out of shape, though, and cramped on the last climb. I find that a high 3 hour average HR means I'm out of shape. When I'm in shape, I recover faster and have a lower HR on the flat, which reduces my average HR. 78% is a good average for me for a hard ride when in top condition.

When I started training hard I was also a bit freaked at the numbers and at how frequently and quickly I achieved them. I even went to a cardiologist. He assured me that I couldn't break it, and said I should keep on keeping on.

More training will probably not raise your absolute LTHR, though you will continue to develop more power at that HR as your training continues. You may also find that your MHR drops a bit.

Thanks for all the replies - I think it was a combination of two things. First I was overdressed - we had a record high of about 73 on Sunday, and I had on a base layer, long sleeve jersey and bib knickers. Never really thought I was overheating, but was very warm the entire ride.

Second, this was the first hard ride I've been on since early October. As was mentioned above, I have clearly lost some VO2 since last fall, and my HR was skyrocketing on every hill or long pull. It just kind of shocked me, and I was curious if others have hit those kind of numbers before.

Sounds like its not uncommon or at least explainable.;)

But averaging 98% of LT for 3 hours? I did not think that was possible. I have not been training long enough for my LT to be any higher than it is in terms of percent of max HR, and I am fairly confident that LT is right at 171 or so.Sure it is. Remember the key point here is "average."

Most likely you were performing above LT for nearly an hour and under LT the rest of the time.
However, even these stats are optimistic, as cardiac drift due to plasma volume levels dropping most likely affected you actual "real time" LT rate.

Most likely your ride went something like this, 1st hour 40 minute above LT at 170
2nd hour, 15 minute above LT at 175, 3rd hour 5 minute above LT at 180.

In any case, those kind of numbers indicate an extremely tough workout. Since you're so fit, I'll assume you know what you're doing, but generally early January isn't the time for these kinds of workouts.....

Sure it is. Remember the key point here is "average."

Most likely you were performing above LT for nearly an hour and under LT the rest of the time.
However, even these stats are optimistic, as cardiac drift due to plasma volume levels dropping most likely affected you actual "real time" LT rate.

Most likely your ride went something like this, 1st hour 40 minute above LT at 170
2nd hour, 15 minute above LT at 175, 3rd hour 5 minute above LT at 180.

In any case, those kind of numbers indicate an extremely tough workout. Since you're so fit, I'll assume you know what you're doing, but generally early January isn't the time for these kinds of workouts.....

Hey RCranium - I'm wondering why you say January isn't the time to do workouts like that. I've been mountain bike riding for about 2 years only got seiously into road biking about 3-4 months ago. I had my AT checked at the local gym and it's at 165, but I typically do my weekend rides averaging 170 for 2-3 hours. I planned on continuing that throughout the year - any reason not to?

The only way to get a decent estimate is with some sort of test. You can spend the money on the expensive one, or you can do a field test (there's a sticky post here on how to do one kind, and there's also a carmichael version)