What's the issue...??
Human bodies do not obey the laws of matter and physics. Esp... girls... *wink* We break all the metabolism rules... and hormones fluctuate. Unlike physical matter, hormone-cascades rule energy flux, flow and balance.
Biological Energy Turnover
Often like life... the more you give, the exponentially more . . . you get.
Energy in alive, biological systems appears to follow the same rule, to me. With more propelling exercise and intense power demands, the human body is the greatest machine to turn over and kick out more outputs than inputs. Mitochondria, our tiny nuclear power-generating plants, double...or even...QUINTUPLE in quantity and quality for future expected thermodynamics. (Conversely, they are degraded with 'hibernation signals' -- insulin, low thyroid, movement-deficiency + subsequent T, hGH, adiponectin hormone declines, high carbs, high F**C-tose, x-s omega-6 veggie oils, diminished daylight/Vitamin D deficiency, EPA+DHA insufficiency, micronutrient/co-factor deficiencies, etc.)
Frank Starling's Rule...of Heart/Muscles Biophysics:
Max Cardiac Output = Max Heart Rate X Max Stroke Volume
For us Paleo people, during functional, natural exercise, how does the heart provide so much ATP, energy packets, with constant and high outputs? At high intensity efforts...like Tabata squats? 100 burpee-pullups? interval 400m sprints? Oly-weight-lifting like dead-lifts and power cleans 8 x3...?? Which then translate effortlessly (without practicing) to faster running, flying across hills, and jumping to never imagined heights...!? I n d e e d y . . . Olympic-lifting explodes vertical-leaping and bounding better than... Superman himself. Another one of our important muscles, the heart, works the same way. It is a muscular biological pump. How strong the heart can pump blood-volume and how efficiently oxygen is supplied are the factors that determine the max work and max volume delivered with every heartbeat. See above Frank Starling formula. With the proper training, the heart muscle cells in fact grow BIGGER (yea)... THICKER (yea-aaahh) with mitochondria, the ATP-power-generators... MORE EQUIPPED with enzymes and co-factors to transfer energy -- fatty acids, lactate, glycogen/glucose -- and to increase 'end-products' neutralizers (Coenzyme Q10).
Our heart cells (cardiomyocytes) are one of nature's best examples of bio-engineering for structure, composition and mechanical genius. They beat for you every second...of your life ~100,000 times per day.
Unless you are . . . Lance . . . only ~46,000 times per day at rest. Uuummm...I'd like to see...umm I mean... study... his... drool-inducing PPARs... *wink* I hear he's finally picking up kettle balls...
What maintains energy supply at peak aerobic exercise in trained and untrained older men? Amir R et al. Gerontology. 2007;53(6):357-61.
In an untrained heart, the volume of mitochondria take up ~5% of the cell. However, in hearts of athletes, mitochondria reside in as much as 20-25% of the heart cell. That is five-times more massive...! Harness the power of your mitochondria... by optimizing your G-flux (see below about energy flow).
Maximal cardiac output increases in response to exercise training. Intensity determines how fast this happens.
In fact excessive endurance exercise (see below 24-h trained endurance results) worsen oxygen efficiency in mitochondria. Short intense, resistance, interval exercise on the hand produce quick generation of mitochondria in a few days, improved glucose utilization, insulin reduction, and activates PPAR-Delta, the switch for anti-inflammatory and pro-immunomodulatory actions in the body.
Reduced efficiency, but increased fat oxidation, in mitochondria from human skeletal muscle after 24-h ultraendurance exercise. Sahlin K et al. J Appl Physiol. 2007 May;102(5):1844-9.
Regulation by exercise of skeletal muscle content of mitochondria and GLUT4.Holloszy JO. J Physiol Pharmacol. 2008 Dec;59 Suppl 7:5-18.
Exercise interval training: an improved stimulus for improving the physiology of pre-diabetes. Earnest CP. Med Hypotheses. 2008 Nov;71(5):752-61.
Regulation of muscle fiber type and running endurance by PPARdelta. Evans RM et al. PLoS Biol. 2004 Oct;2(10):e294.
Genetic variations in PPARD and PPARGC1A determine mitochondrial function and change in aerobic physical fitness and insulin sensitivity during lifestyle intervention. Häring HU et al. J Clin Endocrinol Metab. 2007 May;92(5):1827-33.
Mitochondrial myopathies: diagnosis, exercise intolerance, and treatment options. Tarnopolsky MA, Raha S. Med Sci Sports Exerc. 2005 Dec;37(12):2086-93. Review.
Resistance training, sarcopenia, and the mitochondrial theory of aging. Johnston AP, De Lisio M, Parise G. Appl Physiol Nutr Metab. 2008 Feb;33(1):191-9. Review.
Circuit resistance training in chronic heart failure improves skeletal muscle mitochondrial ATP production rate--a randomized controlled trial. Hare DL et al. J Card Fail. 2007 Mar;13(2):79-85.
Antioxidant enzyme activity is up-regulated after unilateral resistance exercise training in older adults. Parise G, Phillips SM, Kaczor JJ, Tarnopolsky MA. Free Radic Biol Med. 2005 Jul 15;39(2):289-95.
Muscle fat oxidative capacity is not impaired by age but by physical inactivity: association with insulin sensitivity. Morio B et al. FASEB J. 2004 Apr;18(6):737-9.
Strength and aerobic training attenuate muscle wasting and improve resistance to the development of disability with aging. Booth FW et al. J Gerontol A Biol Sci Med Sci. 1995 Nov;50 Spec No:113-9. Review.
What is the preferred energy source of heart and skeletal muscle cells?
Well...it certainly aint Gu or sports drinks or energy bars or carb-loading. As we exercise and become more trained, the preferred source for mitochondria is fatty acids...both our temporarily stored fats in skeletal muscle and the band of saturated fat across the heart...
"Proper heart function relies on high efficiency of energy conversion. Mitochondrial oxygen-dependent processes transfer most of the chemical energy from metabolic substrates into ATP. Healthy myocardium uses mainly fatty acids as its major energy source, with little contribution of glucose."
Metabolic and genetic regulation of cardiac energy substrate preference. de Jong JW et al. Comp Biochem Physiol A Mol Integr Physiol. 2007 Jan;146(1):26-39. Epub 2006 Oct 3. Review.
"Mitochondria in skeletal muscle tissue can undergo rapid and characteristic changes as a consequence of manipulations of muscle use (e.g. MOVEMENT...use it or lose it) and environmental conditions . . . Additionally, a shift of substrate metabolism toward a higher reliance on lipids is observed, structurally reflected as a doubling of the intramyocellular lipid content . . . Transcription factors AP-1 and PPARalpha/gamma and the protein kinase AMPK are signaling molecules that transduce the metabolic and mechanical factors sensed during endurance training into the complex transcriptional adaptations of mitochondrial proteins."
Plasticity of skeletal muscle mitochondria: structure and function. Hoppeler H, Fluck M. Med Sci Sports Exerc. 2003 Jan;35(1):95-104.
G-Flux: Building the Ultimate Body (excerpt)
by Dr John M Berardi (T-Nation.com)
"Well, G-Flux, otherwise known as energy flux (or energy turnover) is the relationship between energy intake and expenditure. It's the balance between the two. Put another way, it's the amount of calories you "turn over". ...Having a high G-Flux is 100%, without a doubt, absolutely critical to building your ultimate body – which I'm assuming includes strong, functional, well-adapted muscle, low body fat, and great health."
Energy In ≠ Energy Out
That's the thermodynamic i-s-s-u-e . . .
G-Radio: 'That's the issue...SoulJaBoytellem...'
*air-kiss-u* ...hormones... philematology...another place ancestral hormonal pathways rule