Re‐entrainment of circadian rhythm of plasma melatonin on an 8‐h eastward flight

Abstract

To estimate the process of re-entrainment we measured the melatonin rhythm on an eastward flight. After the baseline study, 24-hour blood sampling of six male subjects was done on the first and fifth days. During the daytime the subjects were exposed to natural zeitgeber outdoors every day except the blood sampling day. They were analyzed with an illuminometer when under the bright light condition. Four of the six subjects showed orthodromic re-entrainment, another subject showed antidromic re-entrainment, and the other subject kept the baseline pattern of plasma melatonin. The rate of re-entrainment in orthodromic re-entrainment was about 55 min per day. Measuring the circadian rhythm of plasma melatonin has clarified the interindividual re-entrainment difference.

How jet lag impairs Major League Baseball performance

“…From the perspective of both the home and away teams, we found 4,919 instances of teams having at least 2 h of jet lag (Tables S1 and S2). Jet lag was determined by the number of time zones crossed and the number of days since travel, following the general rule of thumb that human circadian clocks resynchronize toward their destination time at a rate of ∼1 h/d (12,13). Given the relatively small number of games involving jet lag of 3 h (Table S1) and the fact that the International Classification of Sleep Disorders diagnosis of Jet Lag Disorder requires travel across at least two time zones (14), we defined jet lag as those games where a team had at least a 2-h jet lag, that is, teams that traveled across at least two time zones, accounting for adaptation to the new time zone (Methods).…”

Preflight Adjustment to Eastward Travel:3 Days of Advancing Sleep with and without Morning Bright Light

“…In one study, 6 individuals were studied before and after an 8-h eastward flight (Takahashi et al, 1999). By the 5th day in the new time zone, 4 advanced, 1 delayed, and 1 did not shift.…”

Phase advance with separate and combined melatonin and light treatment

“…While travelling over 10 time zones to the east, five subjects delayed while five advanced (Spencer et al 1995). In a series of studies by Takahashi et al, one of six subjects adapted by phase delay in response to an 8-h eastward flight (Takahashi et al 1999), seven of eight subjects adapted by phase delay in response to an 11-h eastward flight (Takahashi et al 2001), and six of seven subjects adapted by phase delay in response to another 11-h eastward flight (Takahashi et al 2002). In an abrupt 12-h change from adapted night shift back to day shift, six of nineteen subjects delayed, six advanced and seven hardly changed in the week following the shift (Gibbs et al 2007).…”