|You as a SuppVersity reader should know that there is no "instant gratification" with "doing cardio" and that doing it "in the zone" is totally 90s... 1990s, even ;-)|
Don't worry it's not really about the "fat burning zone"
Luckily Rosenkilde's most recent paper, which happens to be the third spinoff of the high (600kcal/day) vs. medium (300kcal/day energy expenditure from "cardio") training volume that already taught us (you can read more about the exact exercise protocol in the previous SuppVersity articles, below) ...
Learn more about the "Fallacy of Working Out To Burn Calories"
- how messed up the die hard belief that "exercise" just makes you hungry actually is and what the effects of endurance exercise on appetite and energy intake are ("Exercise: Does It Really Make You Hungry? The More You Train, The Less Hungry You Are." | read more)
|Figure 1: Pre & post respiratory exchange ratio (lower value = higher ratio of fatty acid : glucose oxidation) in sedentary control and 300kcal/day group, left; changes in the expression of mitochondrial enzymes (Rosenkilde. 2013)|
So, if it's not the volume, what determines the increase in fatty acid oxidation?
Rosenkilde have probably asked themselves something similar to the above, when they realized that there were no meaningful differences between the subjects in the medium vs. high dose cardio groups. The statistical analyses the researcher conducted did yet reveal, that
- VO2peak, generally regarded as a marker of cardio-respiratory fitness,
- fat free mass, the weight of everything (incl. bones, organs, etc.) that's not fat,
- cycling efficiency, the power output at a given VO2 peak, and the
- mitochondrial complexes II–V, enzymes that facilitate the oxidation of fatty acids,
- Crane, J. D., MacNeil, L. G., & Tarnopolsky, M. A. (2013). Long-term Aerobic Exercise Is Associated With Greater Muscle Strength Throughout the Life Span. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 68(6), 631-638.
- Harber, M. P., Konopka, A. R., Douglass, M. D., Minchev, K., Kaminsky, L. A., Trappe, T. A., & Trappe, S. (2009). Aerobic exercise training improves whole muscle and single myofiber size and function in older women. American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, 297(5), R1452-R1459.
- Ozaki, H., Loenneke, J. P., Thiebaud, R. S., Stager, J. M., & Abe, T. (2013). Possibility of leg muscle hypertrophy by ambulation in older adults: a brief review. Clinical interventions in aging, 8, 369.
- Rosenkilde, M., Reichkendler, M. H., Auerbach, P., Bonne, T. C., Sjödin, A., Ploug, T., & Stallknecht, B. M. (2014). Changes in peak fat oxidation in response to different doses of endurance training. Scandinavian Journal of Medicine & Science in Sports.