The effect of normal and calcium bicarbonate rich water replacement after sauna on muscle behaviour [L'effetto della reidratazione, dopo sauna, con acqua normale e ricca di bicarbonato di calcio sul comportamento muscolare]

Aim. The present investigation was undertaken to study if the different fluid replacement (normal vs calcium bicarbonate rich water) could influence heavy cycling performance and explosive power. The purpose of the present study is to compare the effect of water replacement during sauna bath using 2 different types of water intake: Normal vscalcium rich bicarbonate and very low sodium concentration (Sangemini, Italy) on muscle mechanical behaviour. Methods. A group of 27 healthy and moderately active students, 19 males and 8 females, randomly assigned in 2 groups have performed the same test protocol in 2 sessions. After 5 minutes of warming up on an electro-magnetically-braked cycle ergometer at 50 W for males and 35 W for females, and free revolutions per minute, and 3 minutes of static stretching the subjects performed a counter movement jump (CMJ) and after a modified Wingate test on the cycle ergometer for 60 s. The Wingate test started from 0 rpm and the torque was set at 0.7 Nm/kg body weight for the males and 0.67 Nm/kg body weight for the females. Mechanical power, synchronised with electromyography (EMG) analysis from the mm Vastus lateralis and medialis and Lactate (mM/L) were measured. In the 2nd session the subjects took first a Finnish sauna bath at 90° and 100% humidity. After sauna the subjects drunk water from a bottle ad libitum, and 1 hour after the sauna performed the 2nd test with the same protocol than in the 1st session. The Group A (Control group) took a normal water while the Group B (Experimental group) took a calcium bicarbonate rich water. Results. In the jumping performance the group treated with calcium water bicarbonate showed a significantly increase of height of the centre of gravity (31,6±7,12 cm vs 32,3±7,42 cm p<0,05) while the control group (33,6±6,5 cm vs 32,0±5,6 cm, p=n.s.) was negatively affected by normal water after the sauna bath. Average power, average power/body mass ratio, and EMGrms, no statistically significant differences were founded in both groups. The group treated with calcium water bicarbonate showed a decrease of lactate production post treatment test (12,3±1,9 mM/L vs 10,6±2,1 mM/L, p<0,05) while no difference was noted in the control group (11,9±1,8 mM/L vs 11,4±2,0 mM/L, p=n.s.). Also significant differences was found in the maximal lactate and the average power ratio. Conclusions. It seems that the supplement of calcium bicarbonate rich water could effect positively the negative effect of elevated (H+) on Ca2+ binding mechanism. This is a simple suggestions which, however cannot explain why the experimental subjects drinking calcium bicarbonate rich water developed lower blood [Lac-]. On basis of the present results it can be suggested that drinking calcium bicarbonate rich water helps the athletes to perform strenuous work by reducing the blood [Lac-] accumulation.