Daily rhythms of radiotelemetric and HRV parameters.

For the 12 h-light and 12 h-dark phases, values are reported as means ± SEM of data obtained by averaging multiple 2-min segments acquired every hour over a period of 6 days, in high-aggressive (HA, n = 10) and non-aggressive (NA, n = 10) rats. Abbreviations: HRV = heart rate variability; HR = heart rate; RMSSD = square root of the mean squared differences of successive RR intervals; LF = low-frequency; HF = high-frequency; T = body temperature; LOC = locomotor activity. * and # indicate a significant difference between HA and NA rats (p<0.05 and p<0.01, respectively).