Quantifying H(+) exchange from muscle cytosolic energy catabolism using metabolite flux and H(+) coefficients from multiple competitive cation binding: New evidence for consideration in established theories

The purpose of this investigation was to present calculations of fractional H(+) exchange (~H(+) (e)) from the chemical reactions of non‐mitochondrial energy catabolism. Data of muscle pH and metabolite accumulation were based on published research for intense exercise to contractile failure within ~3 min, from which capacities and time profiles were modeled. Data were obtained from prior research for multiple competitive cation dissociation constants of metabolites and the chemical reactions of non‐mitochondrial energy catabolism, and pH dependent calculations of ~H(+) (e) from specific chemical reactions. Data revealed that the 3 min of intense exercise incurred a total ATP turnover of 142.5 mmol L(−1), with a total intramuscular ~H(+) exchange (‐‘ve = release) of −187.9 mmol L(−1). Total ~H(+) metabolic consumption was 130.6 mmol L(−1), revealing a net total ~H(+) (e) (~H(+) (te)) of −57.3 mmol L(−1). Lactate production had a ~H(+) (te) of 44.2 mmol L(−1) (for a peak accumulation = 45 mmol L(−1)). The net ~H(+) (te) for the sum of the CK, AK, and AMPD reactions was 36.33 mmol L(−1). The ~H(+) (te) from ATP turnover equaled −47.5 mmol L(−1). The total ~H(+) release to lactate ratio was 4.3 (187.9/44). Muscle ~H(+) release during intense exercise is up to ~4‐fold larger than previously assumed based on the lactic acid construct.