Quest for fire.

I want to document some of my recent reading to share my findings with you guys. I’m not going to rewrite the articles that I read so there will be several links at the end.

I wrote a couple of weeks ago that I was on a quest to find whether there was a fat burn zone. There was some disagreement on the DD forum as to weather this ‘zone’ exists. Some guys point to Tabata and High Intensity Interval Training and say that the end result of exercising in the high end anaerobic zone has an overall effect of burning more fat calories than the traditional aerobic exercise at 70% of Heart rate max . Originally this interested me because I luv when it’s intense (plus I’m fat). It sounded like the best of all worlds. However, the first two weeks I used my heart monitor with the kettlebells, I noticed an unexplainable drop in intensity (expressed as heart rate max) on the next workout day after an especially great day. The trend continued downward for the next two weeks. I was not happy.

The next book that I read after the one that gave me a panic attack about acidosis was another old Heart Rate Monitor book that I picked up used at Amazon. This book’s main focus was using the monitor to work at 70% HRMax. The book was geared to runners, but the theory was interesting. The recommendation was based on the supposition that people over train. The author’s recommendation was to begin training up to, but not exceeding 70% HRMax (totally different from high intensity type training). His recommendation was to do this for six weeks. The long term goal is fast training maintaining a HR of no less than 85% HRMax with the alternating or supplimental workouts remaining under 70% HRMax. There was a lot of antecdotal evidence that the runners were eventually able to run faster at 70% HRMax at the end of the six weeks, they had more energy, and their race times increased. The basis of his theory is essentially one of ‘conservation and restoration.’ I found this extremely interesting. I wasn’t convinced that I was overtraining, but I was confused as to why my ‘tank’ was running dry. Did I need to conserve my energy?

So...I began to read several articles on line. This may be old news for you guys, some of it was for me, but what I found out was that there are three types of muscles: slow twitch, fast twitch and the other fast twitch. I knew that. What I didn’t know was that each type of muscle uses ATP as its fuel, but depending on the type of muscle and intensity of the exercise, a different ‘source’ for creating ATP is used. For immediate energy there is only a few seconds worth of fuel (creatine phosphate - a high energy phosphate compound) stored in the muscle cells. This is used for the faster fast twitch muscles (fight or flight, sprints, etc.). The second ‘source’ is glycogen. Muscle cells first split the glycogen into glucose( a sugar ) and then metabolizes it to make ATP. Glycogen is stored in the muscles, blood stream, and liver. It is converted to ATP via the might mitochondria. The third, and most abundant, source is fat which is also converted to ATP at the lower heart rate ranges.

To me this is the Holy Grail. First, I now knew that there is a fat burn zone. I know this intuitively from when I used to jump rope for 40 to 60 minutes back in college and had 8% BF. (Karate too, but no lifting, or running). Secondly, the idea of conservation and restoration was new to me. It takes 24 to 48 hours to replenish your ATP reserves. If you keep hitting it hard, it’s no wonder your batteries run dry…especially if you're an out of shape, 45 year old, fat slob. This made total sense.

So the benefits of working out at the aerobic zone level are: increased level of oxidizing body fat; restoration of ATP and conservation of glucose for hitting it harder during your anaerobic workouts; and increased mitochondrial density.


Here are some of the great articles I read:


Muscle Fibers - An In Depth Analysis: (Tonic And Phasic Muscles - The Original Name For Fast and Slow Twitch and Why It Still Applies! – and - The Body's Three Energy Systems Used For Movement)

Muscle Fibers - An In Depth Analysis Part 2: (Muscle Fibers Makeup and Purpose)

Muscle Fibers - An In Depth Analysis Part 3: (Mitochondrial Density = An Increase In - Fat Burning, Muscle Mass, & Your Ability To Train)

Direct Comparisons of Fuel use during Low, Moderate, and High Intensity Exercises: (Great article that refutes HIIT as a more effective means to burning fat.)