title: The dynamics of changes in blood electrolyte and lactic acid concentrations, haematocrit, arterial blood pressure and heart rate in canoeists during 4 hours of rest after maximal effort.
abstract: In 12 canoeists determinations were carried out of the haematocrit value, and plasma concentrations of sodium, potassium and lactic acid during 4 hours of rest following maximal effort. The age of the sportsmen was from 18 to 21 years. The haematocrit was significantly increased immediately after the effort but in the first hour of restitution it fell below the resting value and increased then reaching the initial value only in the 4th hour. Serum lactic acid concentration increased in the first minutes of rest and then it decreased gradually reaching the resting value in the 4th hour. The concentration of sodium was not significantly changed throughout the whole period of restitution, when the haematocrit changes were taken into account. The concentration of potassium was very high immediately after the effort, but it fell below the resting value in the 15th minute, rose to the resting value in the 1st hour and in the 2nd hour it continued to rise much above the resting value, and only in the 4th it decreased again to the initial value. The author supposes that the second rise of the serum potassium level beginning in the 1st hour of restitution after maximal effort could be due to insufficient supply of ATP for maintaining the needs of the ionic pump or to secondary loss of water from the cells with a consequent rise in the intracellular hydrogen ion concentration.
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure; D004573:Electrolytes / Q000097:blood*; D006339:Heart Rate; D006400:Hematocrit; D006801:Humans; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D005082:Physical Exertion; D011188:Potassium / Q000097:blood; D012146:Rest; D012964:Sodium / Q000097:blood; D013177:Sports; D013997:Time Factors
chemical_list: D004573:Electrolytes; D007773:Lactates; D019344:Lactic Acid; D012964:Sodium; D011188:Potassium