Blood biochemical status of miniature swine during submaximal and exhaustive exercise

Simultaneous arterial (left atrial) and mixed venous (right atrial) blood samples were anaerobically drawn from 14 miniature swine (mean weight = 25.0 +/- 1.7 [SE] kg) in order to examine the adequacy of these animals as a model for the exercising human. Samples were drawn: 1) at rest; 2) during exercise that elicited 80.4 +/- 1.2% of the animals' measured maximal heart rates; 3) at exhaustion; and 4) during the 4th min of a standing, resting recovery period. At rest, the animals were mildly alkalotic (pHa = 7.497 +/- 0.016) and hypocapnic (pCO2a = 29.6 +/- 1.2 torr), with low hematological values (arterial hemoglobin = 6.66 +/- 0.18 mmol X 1-1; arterial hematocrit = 32.0 +/- 0.9%) and slightly elevated catecholamine concentrations. During the submaximal exercise, there were no statistically significant changes in the arterial blood pH or in plasma sodium (Na+) and chloride (Cl-) concentrations, with significant decreases observed in Hcta, pCO2a, and increases in arterial plasma norepinephrine, total protein, and potassium (K+) concentrations. At exhaustion, pHa and pCO2a decreased further, with increases noted in the arterial plasma concentrations of K+, epinephrine, total protein, and the Hct but not in Na+ or Cl-. During recovery, arterial lactate averaged 20.54 +/- 0.71 mmol X 1-1. Venous changes were similar to those observed in arterial blood, with a mean pHv of 7.168 +/- 0.043 and arterial lactate = 21.08 +/- 0.90 mmol X 1-1 during recovery. Exercise-induced hemoconcentration was similar for both arterial and venous sample sites during both the submaximal and exhaustive exercise.(ABSTRACT TRUNCATED AT 250 WORDS)