OXYGEN-UPTAKE, HEART-RATE AND BLOOD LACTATE CONCENTRATION DURING A NORMAL TRAINING SESSION OF AN AEROBIC DANCE CLASS

The aim of this research was to investigate the physiological response s and, in particular, the participation of lactic acid anaerobic metab olism in aerobic dance, which is claimed to be pure aerobic exercise. In contrast to previous studies, that have put subjects in very unfami liar situations, the parameters were monitored in the familiar context of gymnasium, practice routine and habitual instructor. A group of 30 skilled fairly well-trained women performed their usual routine, a co mbination of the two styles: low (LI) and high impact (HI), and were c ontinuously monitored for heart rate (HR) and every 8 min for blood la ctate concentration ([La-](b)). Of the group, 15 were tested to determ ine their maximal aerobic power ((V) over dot O-2max) using a cycle-er gometer. They were also monitored during the routine for oxygen uptake ((V) over dot O-2) by a light telemetric apparatus. The oxygen pulses of the routine and of the corresponding exercise intensity in the inc remental test were not statistically different. The mean values in the exercise session were: peak HR 92.8 (SD 7.8)% of the subject's maxima l theoretical value, peak (V) over dot O-2 99.5 (SD 12.4)% of (V) over dot O-2max maximal [La-](b) 6.1 (SD 1.7) mmol.l(-1) and mean 4.8 (SD 1.3) mmol.l(-1). Repeated measures ANOVA found statistically significa nt differences between the increasing [La-](b) values (P < 0.001). In particular, the difference between the [La-]b values at the end of the mainly LI phase and those of the LI-HI combination phase, and the dif ference between the samples during the combination LI-HI phase were bo th statistically significant (both P = 0.002 and P = 0.002). The simil ar oxygen pulses confirmed the validity of the present experiment desi gn and the reliability of HR monitoring in this activity. The HR, (V) over dot O-2 and, above all, the increase of [La-]b to quite high valu es, showing a non steady state, demonstrated the high metabolic demand made by this activity that involved lactic acid metabolism at a much higher level than expected.