Physiological and metabolic effects of a 25 km race in female athletes.

Nine female athletes were examined before and after a 25 km race (German championship). Their average running speed was 3.89 m/s. Postexercise weight loss was 1.60 +/- 0.58 kg or 2.87% of body weight, the mean rectal temperature increased by 1.04 +/- 0.52 degrees C to 38.4 +/- 0.54 degrees C. Leucocytes, but no other blood parameters (hemoglobin, hematocrit, erythrocytes, MCV) showed a marked rise after the race. Blood lactate rose from 1.86 +/- 0.34 to 4.97 +/- 1.19 mmol/l but hypoglycemia was not present in any of the athletes at the end of exercise. After the run serum enzymes showed lower increases than those observed in men for the same exercise duration. Serum sodium, chloride and potassium showed similar increases, inorganic phosphate higher increments than found in men. The comparatively high rise in free glycerol suggested a marked mobilization of lipid substrate, whereas the increment in serum of free fatty acids was lower than in male subjects after similar athletic events. A lowering of neuromuscular excitability (m. vastus medialis quadricipitis) was found after the race but the changes were significant only for the fibers responding to longer durations of stimuli (0.3-30 ms).