Normative references of heart rate variability and salivary alpha-amylase in a healthy young male population

Table 3 Day-to-day reproducibility of heart rate variability and salivary alpha-amylase

	n	Intraclass correlation coefficients
Heart period	417	0.67
lnHF	417	0.59
lnLF	417	0.50
ln(LF/HF)	417	0.54
SD of normal-to-normal intervals	417	0.56
Root mean square of successive differences	417	0.58
Raw sAA	430	0.56
Square root transformed sAA	430	0.61
Natural log-transformed sAA	430	0.60

HF: high frequency component; LF: low frequency component; sAA: salivary alpha-amylase.

ISSN: 1880-6805