staying in the fat burning zone

wanderinjack

SO.. I did a 4 mile run this morning at an aerobic fat burning pace (used a heart monitor) and my blood sugar was the 95 at the beginning and 95 at the end. what does that mean? My theory is that I was successful in achieving a workout that did not elevate blood sugar....in other words, I stayed in the fat bring zone. Watcha think?

http://philmaffetone.com/want-speed-slow-down/
http://fatburningman.com/mark-sisson-the-carb-loading-myth-how-to-fuel-athletics-with-fat-advanced-heart-rate-training/

wabmester

How soon after the run did you test? The rise in glucose happens during exercise recovery.



Metabolic characteristics of keto-adapted ultra-endurance runners

Graph A shows you need to wait about an hour after the run.

Foamroller

Have you done a HR max pulse test? My cycle instructor said it can vary +/- 15 bpm from estimated calculators, when I took mine. It's also sport specific. So it's higher for running than cycling.

Btw, l think being keto adapted changes the map concerning "fat burning zone". That's exercise physiology knowledge based on being a sugar burner. The body won't really use glycogen before it gets over moderate - High intensity anyway. Being keto adapted and exercising is very understudied. So we're frontiers or guinea pigs So it's good to share experiences!

wanderinjack

wabmester wrote: »

How soon after the run did you test? The rise in glucose happens during exercise recovery.



Metabolic characteristics of keto-adapted ultra-endurance runners

Graph A shows you need to wait about an hour after the run.

I tested 1/2 hour after my run.

wanderinjack

Foamroller wrote: »

Have you done a HR max pulse test? My cycle instructor said it can vary +/- 15 bpm from estimated calculators, when I took mine. It's also sport specific. So it's higher for running than cycling.

Btw, l think being keto adapted changes the map concerning "fat burning zone". That's exercise physiology knowledge based on being a sugar burner. The body won't really use glycogen before it gets over moderate - High intensity anyway. Being keto adapted and exercising is very understudied. So we're frontiers or guinea pigs So it's good to share experiences!

I'm using Phil Maffetone's 180 formula. Since he regularly works with fat burning athletes I'm assuming its a good place to start

wabmester

Probably a good test then. Read that study if you want to be convinced your heart rate can go much higher and still stay in the fat-burning zone now that you're low carb.

wanderinjack

Thanks, Volek & Phinney of course! Those guys rock

Foamroller

wanderinjack wrote: »

Foamroller wrote: »

Have you done a HR max pulse test? My cycle instructor said it can vary +/- 15 bpm from estimated calculators, when I took mine. It's also sport specific. So it's higher for running than cycling.

Btw, l think being keto adapted changes the map concerning "fat burning zone". That's exercise physiology knowledge based on being a sugar burner. The body won't really use glycogen before it gets over moderate - High intensity anyway. Being keto adapted and exercising is very understudied. So we're frontiers or guinea pigs So it's good to share experiences!

I'm using Phil Maffetone's 180 formula. Since he regularly works with fat burning athletes I'm assuming its a good place to start

All calcs are ESTIMATES based on variables like gender, age etc. As mentioned, an individual can vary up to 15 heartbeats either up or down from the estimate. Which means that your "fat burning zone" might be 15 beats higher or lower than the guesstimate. My cycling VO2 max is around 190 (it has gone UP since going lowcarb!). According to 220-age it should be 175 bpm...In running I've seen HR go up to 209 bpm. If you're gonna invest a considerable amount of time to expand your aerobic muscle conditioning, I would invest in trying to find out YOUR personal max pulse.

Until you test it, you may base your training on faulty numbers. The 180-age could be accurate in your case. It could be inaccurate.... Adding to injury, HR is a very finicky metric. It varies a lot due to mood, recovery, caffeine, stress level etc etc. One needs a lot more data points to establish patterns, rather than using one quite arbitrary number.

Good luck

wanderinjack

Thanks, How does one arrive at their own max heart rate and what has that got to do with vo2 max?

wabmester

There are estimations for converting between VO2 and HR, but they're just estimates.

I simply use the "breathe through the nose test". If you can breathe through your nose while you run, you're probably still in the aerobic zone. For me (54 yo), that maxes out around 140-150 bpm.

Panda_Poptarts

I have questions! Using the 180 formula, I should be staying around 155 max heart rate. I find it a personal achievement to get my HR above 170bpm, and regularly push myself that high. Would I actually be burning more fat by staying lower?

wanderinjack

Yes you burn more fat by staying lower because exceeding the MAF rate puts you into the sugar burning zone.

Dragonwolf

wanderinjack wrote: »

Yes you burn more fat by staying lower because exceeding the MAF rate puts you into the sugar burning zone.

This is one of the places where things get tricky. This statement is true during the workout, because then the body is forced to burn glycogen.

However, for a low carb athlete that isn't carb-loading, that's burning glycogen stores that aren't readily being replaced. Then what (assuming you don't tap out your glycogen stores)? There haven't been many studies on that with fat burner subjects.

The story with fat burners really starts before you get to the anaerobic zone, though, because your anaerobic zone actually moves higher. In other words, while your sugar-burning aerobic threshold was, say, 110 bpm, once you're fat adapted, that could go up to, say, 170. (Dr. Peter Attia saw a nearly 60 bpm increase in his -- http://eatingacademy.com/how-a-low-carb-diet-affected-my-athletic-performance )