schedule of the destination time zone.
poor cognitive function. It can impair the judgment and performance of politicians, diplomats
and military personnel. It is a disorder that deserves serious attention due to the possible public
such as irritability and depression. Going hand in hand with the somnolence during the
destination wake times, is the inability to initiate and/or maintain sleep during the new desired
sleep times. GI disturbances are another common problem.
growing body of research on the subject. Different studies have shown increased risk of the
following disorders: cardiovascular disease, diabetes, cancer, cognitive deficits.
the circadian clock if no special measures are taken. Humans have a tendency to phase delay at
least slightly. Also, it much easier to stay up later than the circadian bedtime than it is to go to
bed earlier than the inner clock dictates. If one could simply go to sleep because hands on a
clock said it was time, then there would be few circadian rhythm disorders and no such thing as
travel, but the circadian clock phase advances at a rate of only 57 minutes per day after
eastward travel. Thus, if nothing special is done to mitigate the jet lag, the symptoms resolve
due to natural re-entrainment after approximately 7-10 days.
destination sleep/wake schedule? Bright light, low dose melatonin and prescribed sleep/wake
schedules can reduce significantly the time it takes to re-align to the new time zone. However,
for optimal results the recommendations usually need to be tailored to the individual traveler
and take into account such things as the number of time zones traversed, the direction of travel,
time of day of departure, lay overs, sleep schedule/habits prior to departure. It is complicated to
formulate these recommendations and many sleep experts recommend making changes before
travel. Few people have the motivation to do this.
Here are some general recommendations to help adjust. Bright light therapy will be the most
temperature minimum). If one is attempting to advance sleep onset because travel is in the
eastern direction (i.e., make sleep occur earlier), then light exposure needs to be after CTmin. If
it occurs before, then it will further delay sleep onset the following night. Conversely, if travel is
in the western direction and the need is to phase delay, the light exposure needs to come
running according to the previous sleep/wake schedule. Calculate the timing of CTmin based on
habitual wake time for the previous two weeks. CTmin is approximately two hours before
habitual wake time. On subsequent days, the CTmin will have advanced at least 57 min, let’s
call it one hour for simplicity, and likely more than that if light exposure has been timed
appropriately. However, it will do no harm in the case of eastward travel and attempts to phase
advance if light exposure comes a bit after CTmin, whereas a great deal of effort is wasted if
light comes before CTmin. Therefore, advance the timing of bright light exposure, preferably
outdoor light, by one hour per day for the first week and likely by that time most jet lag
symptoms will have resolved.
keep the nap short, preferably only 10 minutes but certainly no longer than 30 minutes.
time zone, people will still feel that alertness in the daytime is diminished. Sleepiness will still
occur around the time of CTmin.
transient global amnesia with use of short-acting benzodiazepines.
© 2013 Dr. Lisa Shives