Autonomic Nerve Tone After an Eastward Transmeridian Flight as Indicated by Heart Rate Variability

Abstract

Background:Transmeridian flights commonly cause the physical distress and somnolence known as jet lag. Because the influence of jet lag on autonomic nerve tone (ANTi is unclear, we studied its influence by evaluating heart rate variability before versus after a flight from Tokyo to San Francisco. Methods:We recorded the ambulatory electrocardiograms of 12 healthy young men for 11 days, i.e., 3 days in Tokyo before the flight and 8 days in San Francisco following the flight. Heart rate variability was determined by power spectrum analysis. After calculating high frequency power (0.15–0.4 Hz, HF), low frequency power (0.04–0.15 Hz, LF), and LF/HF, we evaluated autonomic nerve tone using HF and LF/HF as indices of the activity of sympathetic and parasympathetic tone, respectively. In addition, we analyzed the circadian rhythm of autonomic nerve tone by the maximum entropy method. Results:Parasympathetic nerve tone was found to increase during the flight. The time required for the ANT to return to preflight levels differed between the waking and sleeping periods, being 5 and 7 days, respectively. Conclusions: ANT varied for 1 week after an eastward transmeridian flight. A.N.E. 2000;5(1):53–59