Effect of acute weight reduction on hematology and blood chemistry in Thai boxers

Abstract

To assess the effect of acute weight reduction on hematology and blood chemistry, eight male Thai boxers from Dejratana Camp decreased their body weight 1.5 kg or mroe than 1.5 kg from the initial body weight by running and rope jumping within 50-90 min at the ambient temperature of 33.7+0.9 degree C and relative humidity of 79.0+ 2.5%. Prior to the start of the acute weight reduction regimens the physical fitness were test in the control period which had been separated from the acute weight reduction period for 7 days. Venous blood samples were obtained at rest (in control period after an overnight fast), immediately after acute weight reduction and after rehydration period. The relative change in plasma volume (% PV) was calculated with the use of hematocrit (Hct) and hemoglobin (Hb). After acute weight reduction plasma volume was 6.11% less than the control period and returned to increase (4.87%) after after rehydration. After acute weight reduction the concentration of several blood parameters were elevated from the control level such as erythrocytes count (7.45%), Hct (2.70%), Hb (5.52%, P<0.05), leukocytes count (23.32%, P<0.05), plasma sodium (3.57%, P<0.001), plasma calcium (10.84, P<0.05), plasma chloride (2.52%), plasma osmolality (1.43%), plasma albumin (5.83%, P<0.01), plasma globulin (8.41%), plasma glucose (14.68%), P<0.05) BUN (17.24%, P<0.05), uric acid (32.69%, P<0.001), creatinine (0.86%), alkaline phosphatase (5.19%), PGOT (25.45%), PGPT (11.11%), CPK (39.84%), and LDH (20.70%). But plasma potassium significant decreased (5.13%, P<0.01) after acute weight reduction. This may be due to heavy sweating during acute weight reduction. And after 5 hr rehydration these blood parameters tended to return to the resting control value. Nevertheless, these changes were still in the usually accepted normal range except CPK and LDH. Plasma CPK and LDH of these Thai boxers were higher than the normal level both in control and in experimental period. The elevation of both enzymes in the resting control period