How SportLegs Works
How SportLegs works
When we begin exercise, muscles normally respond by flooding with more lactate fuel than they can immediately use. You can see it as the “pump up” response familiar to bodybuilders. This is likely an evolutionary development that helped our ancestors dodge unplanned, brief deadly threats. But it’s no longer helpful for modern humans, planning sports or exercise lasting more than a few minutes. Excess lactate quickly decays into lactic acid, useless as muscle fuel. Worse, lactic acid impedes energy transfer and “gums up” your muscle fuel system, leaving your muscles literally starving for fuel. You feel “out of gas,” with screaming muscles. Not fun.
SportLegs updates your muscles’ fuel system
SportLegs simply replicates your body’s natural signal to curb lactate fuel production early. Lactate fuel production is controlled by lactate concentration in your blood. Taking SportLegs half an hour before exercise raises blood lactate concentration just enough to curb the ordinary lactate surge, the source of lactic acid. Your muscles’ fuel system is effectively updated to supply the modern athlete: Within half an hour, you perform with an unmistakably raised Lactate Threshold “burn point,” allowing you to go faster, easier. Improved muscle fuel efficiency yields better endurance, too. Finally, reduced lactic acid accumulation gives less retention of free radicals and other metabolic wastes in muscle tissues, for faster recovery and less next-day soreness. SportLegs’ effect is temporary, wearing off after about two hours without re-dosing. But skiers, cyclists, ultrarunners, 24-hour solo and RAAM competitors routinely re-dose with SportLegs to keep lactic acid away.
History and research
Science no longer regards lactic acid, or its non-acidic form lactate, as a waste product of anaerobic exercise, as it did for most of the 20th century. Lactate is now recognized as a primary muscle fuel transport medium directly through tissue and even cell membranes, during exercise and at rest. Lactate is the primary ingredient in SportLegs. What’s now called the Lactic Acid system is recognized as the primary anaerobic energy transport system, supplying short-term muscle energy until lungs and heart can catch up. Since most competitive sports are sequences of short-term activities, optimizing our Lactic Acid system is a competitive advantage. During peak exertion, blood may actually transport more lactate than glucose to fuel muscles (20). At rest and during light exercise, your muscles balance lactate production and consumption, producing just as much lactate as they consume (21). But kicking up the pace upsets the balance:
How Lactic Acid forms
When you start serious exercise, muscles produce more lactate than they consume (1,2,3,4,5), particularly at altitude (2,6), which is why skiers other high-altitude competitors suffer more severe “burn”. This continues until the concentration of lactate in your blood rises enough to signal muscles to stop producing excess lactate (7,8,9,10,11,12,13). Until this happens, a “domino effect” begins which limits your subsequent performance: Lactate accumulates in muscles; limbs “pump up” and feel heavier. The harder you exercise, the more lactate accumulates (14). Lactate accumulated from flow imbalance decays, quickly becomes acidic (14,15) and even less mobile (16), further exacerbating accumulation. This “Lactic Acidosis” is classically associated with reduced Lactate Threshold, meaning a lowered “burn point”. Muscular strength suffers as well (17,18,19).
Lactate helps prevent lactic acid. Clues since 1967
Muscles switch from lactate overproduction to net lactate consumption in response to a rise in blood lactate concentration, whether blood lactate is raised naturally or from exogenous infusion (7,8,9,10,11,12,13). That’s precisely what SportLegs accomplishes. It’s 88% lactate (with balanced calcium, magnesium and Vitamin D to speed absorption). Taken half an hour before exercise, SportLegs raises blood lactate, improving lactate transfer and thus muscle function, facilitating a noticeably higher Lactate Threshold “burn point”, less limb “pump” and heaviness. Reduced lactic acid accumulation gives less retention of free radicals and other metabolic wastes in muscle tissues, for faster recovery and less next-day soreness.
How taking SportLegs afterward can help recovery
“Because lactate is combusted [metabolized] as an acid (C3H6O3), not an anion (C3H5O3), the combustion of an externally supplied salt of lactic acid, CHO3H5O3- + H+ + 3O2 → 3H2O + 3CO2 effects the removal of the proton taken up during endogenous lactic acid production (Gladden, L. B. and J. W. Yates, J Appl Physiol 54:1254-1260, 1983). A side benefit of alkalizing the plasma by feeding lactate would be to enhance movement (efflux) of lactic acid from active muscles into plasma, a process which is inhibited by low (relative to muscle) blood pH. (Brooks, G. A. and D. A. Roth, Med Sci Sports Exerc 21(2):S35-207, 1989; Roth, D. A. and G. A. Brooks, Med Sci Sports Exerc 21(2):S35-206, 1989). Moreover, maintenance of a more normal blood pH during strenuous exercise would decrease the performer’s perceived level of exertion. The conversion of lactate to glucose in the liver and kidneys also has alkalizing effects by removing two protons for each glucose molecule formed, 2C3H5O3 + 2H+ → C6H12O6. Thus, whether by oxidation or conversion to glucose, clearance of exogenously supplied lactate lowers the body concentration of H+, raising pH.”(22)
- Ahlborg, G. Mechanism of glycogenolysis in nonexercising human muscle during and after exercise. Am J Physiol 248:E540-E545, 1985.
- Brooks, G. A., G. E. Butterfield, R. R. Wolfe, et al. Decreased reliance on lactate during exercise after acclimatization to 4,300 m. J Appl Physiol 71:333-341, 1991.
- Brooks, G. A., E. E. Wolfel, G. E. Butterfield et al. Poor relationship between arterial lactate and leg net release during steady-state exercise at 4,300 m altitude. J Appl Physiol 275:R1192-R1201, 1998.
- Richter, E. A., B. Kiens, B. Saltin, N. J. Christensen and G. Savard. Skeletal muscle glucose uptake during dynamic exercise in humans: role of muscle mass. Am J Physiol 254:E555-E561, 1988.
- Wahren, J., P. Felig, G. Ahlborg and L. Jorfeldt. Glucose metabolism during leg exercise in man. J Clin Invest 50:2715-2725, 1971.
- Brooks, G. A., E. E. Wolfel, B. M. Groves, et al. Muscle accounts for glucose disposal but not blood lactate appearance during exercise after acclimatization to 4,300 m. J Appl Physiol 72:2435-2445, 1992.
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- Brooks, G. A., T. D. Fahey, T. P. White, K. M. Baldwin. In Exercise Physiology. Human Bioenergetics and its Applications. 3rd edn. pp804-805. Mayfield Publishing Company, 2000.
- Roth, D. A. The sarcolemmal lactate transporter: transmembrane determinants of lactate flux. Med Sci Sports Exerc 23:925-934, 1991.
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- Brooks, G. A. Method and composition for energy source supplementation during exercise and recovery. U. S. Patent #5,420,107, May 30, 1995.