Question about Anaerobic vs Aerobic threshold

Anaerobic training via intervals is useful for racing, increasing cardio fitness, reducing recovery time and developing your capacity for endurance at higher and higher thresholds.

As you train and your fitness level increases, so does your capacity to sustain longer periods of time at a higher heart rate--this is a GOOD thing, not a bad thing. Max heart rate is relative, not static--please do not use an age chart--where do you think Lance Armstrong would hit on that?

It's not a bad thing to burn glycogen -- that's what it's there for--quick energy. The ability to burst forth with energy is also useful in the event you should be chased by a pack of bad guys, so worry not!

Working out is not only for burning fat, but for improving overall fitness. What you're doing sounds just fine--sounds like you're an athlete, improving your game! The body would burn muscle if you depleted your glycogen, so just keep yourself fueled and keep on what you're doing.

blessings.

I just started reading up on this concept...apparently aerobic threshold (65-75% of your maximum heart rate/MHR) is the point at which you burn the most fat calories (ie. "fat burning zone") and the anaerobic threshold (~80% of MHR) is where your body is more likely to burn glycogen and/or muscle instead of fat...or something.

Most articles online recommend prolonged aerobic workouts to burn fat, instead of shorter high intensity workouts which simply deplete glycogen.

Here's my concern: I either bike or run when I work out (30 miles or 10 miles, respectively) and I've always just gone as hard as I can, regardless of my heart rate. This usually works out to an average HR of 172 over an 80-100 minute period. My max HR is 201. Which means I'm at anaerobic threshold (85% of maximum) for a prolonged period...does this mean I'm not burning fat? But instead burning muscle? Should I work out less hard to lose more fat even though that's so damn counter-intuitive?

Please help, this is really confusing...

Long distance running and biking are notorius for burning muscle. That's why most runners and bikers upper body's are pretty lanky.

well, that presumes that you don't do any other work outs. I am a cyclist and spin instructor . . . but I am also a paddleboarder -- MAJOR upper body and core strength training, and I am a dancer forever - strength and cardio combined. I enjoy getting the majority of my workouts outside of the gym -- makes for a happy me.

BTW, I rode a 21% grade for a mile last week -- that takes some serious strength. Cycling does a body good.

well, that presumes that you don't do any other work outs. I am a cyclist and spin instructor . . . but I am also a paddleboarder -- MAJOR upper body and core strength training, and I am a dancer forever - strength and cardio combined. I enjoy getting the majority of my workouts outside of the gym -- makes for a happy me.

BTW, I rode a 21% grade for a mile last week -- that takes some serious strength. Cycling does a body good.

Agree. The majority of people who competitively run or bike ( which where I live in CA is a lot) in my gym rarely, and that's rarely, do any strength training for upper body. And you can definitely tell by their physiques.

And thanks bloodstar, that was actually a very helpful article...It seems that it doesn't matter too much whether I'm burning calories from fat or carbs, simply that I am burning calories.

Still not sure how I should go about revising/diversifying my fitness regimen, but I'm going to have to to get over this plateau...

Thanks again for the helpful advice

caveat: IANAFE - (I Am Not A Fitness Expert)
The first question you should ask is: what is your goal with your workouts? If it's simply to be able to run faster, bike faster, go further, I'd say, perhaps in a seemingly contrary way, taper off your biking and running for a week or two, (since I don't know how often you run/bike, it's hard to say how much and all that) and throw in some other cross training (yeah, I've become a big fan of cross training) change up how your muscles are working.

Often times we get used to running the same distance, biking the same distance, always at the same intensity. and your body responds by becoming more efficient at doing just that. Muscles get trained to perform certain actions and it becomes easy to find your gains becoming more and more limited.

There are a pair of ideas you can try out to increase your overall speed and stamina. the first is interval workouts, For example, say you want run your 10 miles faster (almost like you're training for a 15K race), find a track or some well marked distance, figure out what pace you want to run your 10 miles at, and run 1 mile at that pace. (in theory, for longer distances you can try longer intervals, but let's stick to a simple methodology first). Have a short rest period (depending on how in shape you are, that can range from a quarter mile to a full mile jogging) then run that mile at that pace again. In your case, if you can run 10 miles comfortably, I'd say start with 4 - 6 1 mile intervals. (make sure you warm up first). depending on how you feel and how comfortable you are, you can do that either once a week or once every two weeks or so.

The second idea is related to the first, but instead of having a measured time, you use what's called Fartlek running, (you can google interval training and fartlek for much more detailed information) Which performs a similar function as interval training, but isn't structured and more based on the idea of working both the aerobic and anaerobic systems.

Again, I'm not an expert. and I'd suggest checking out any local running or cycling groups for people who have probably forgotten more than what I know.