Figure 1

Unadjusted effects of the NPY genotype on indices of heart rate variability, stratified by PSS score.
LF, low frequency power; HF, high frequency power; LF/HF, ratio of LF to HF; RMSSD, the root mean square of successive heartbeat interval differences. PSS, Perceived Stress Scale; Low- and high-PSS were determined by a median split at PSS score 21. *pā<ā0.05.