Heart Rate Variability
HEART
Heart rate
variability (HRV) was monitored before, during, and after the commute
using an ambulatory ECG (Holter) monitor (GE Seer Light or SEER Light
Extend recorders). Measures of HRV were calculated as outlined by
the Task Force of the European Society of Cardiology and the North
American Society of Pacing and Electrophysiology, and both time (standard
deviation of normal-to-normal intervals [SDNN]; root mean square of
the successive differences [RMSSD]); and frequency domain measures
of HRV (low-frequency spectral power [LF]; high-frequency spectral
power [HF]).