Post-exercise heart rate variability recovery after 800-m endurance run load among Cameroonian adolescent's males

The 800-m(m)run is part of Physical Education classes in Cameroon,after which arrhythmias may occur during recovery.Hence,this study aimed at determining relationship between 800-m run loads on cardiac autonomic recovery among school adolescents.Forty-two male adolescents(aged[17-1]years)performed 800-m.Post-exercise heart rate variability(HRV)was recorded during 5-min(min)(HRV5-min)and 15-min(HRV15-min)in time:Standard deviation of normal to normal(SDNN);Root mean square of successive differences(RMSSD)and frequency domain(LH:Low frequency,HF:High frequency,TP:Total power).Rating of Perceived Exertion(RPE)and blood lactate concentration(BLa)were measured after exercise.In HRV5-min,RPE was associated with SDNN(r=-0.44,p<0.01)and RMSSD(r=-0.38,p<0.05).BLa was correlated with SDNN(r=-0.38,p<0.05)and RMSSD(r=-0.56,p<0.001)in the time-domain,LF(r=-0.64,p<0.001),HF(r=-0.58,p<0.001)and TP(r=-0.61,p<0.001)in frequencydomain.Moreover,RPE was correlated with LF(r=-0.44,p<0.01),TP(r=-0.49,p<0.01)while exercise duration with HF(r=-0.38,p<0.05).In HRV15-min,BLa was correlated with RMSSD(r=-0.53,p<0.001)and SDNN(r=-0.68,p<0.001).RPE was negatively correlated SDNN(r=-0.53,p<0.01)and RMSSD(r=-0.44,p<0.01).BLa was associated with HF(r=-0.55,p<0.001),TP(r=-0.50,p<0.01)and RPE with LF(r=-0.51,p<0.01),HF(r=-0.50,p<0.01),TP(r=-0.49,p<0.01).In addition,exercise duration was negatively linked to HF(r=-0.36,p<0.05).This study outlined that in untrained adolescents an increase of 800-m loads is associated with a slow vagal indexes of HRV during the recovery.