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Canada Communicable Disease Report
Volume 29
ACS-3
1 April 2003
An Advisory Committee Statement (ACS)
Committee to Advise on Tropical Medicine and Travel (CATMAT)*
TRAVEL STATEMENT ON JET LAG
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Definition
The term "jet lag" refers to a variety of physical and psychological symptoms
associated with the rapid crossing of multiple time zones (meridians). These
symptoms are due primarily to a disturbance of the intrinsic or endogenous
circadian rhythm and sleep cycle.
Circadian rhythms affect a wide range of biologic measures and functions,
such as body temperature, blood pressure, and hormone secretion. Endogenous
melatonin, secreted by the pineal gland, contributes to the physiologic regulation
of circadian rhythm(1). Light exposure inhibits its secretion and,
as a result, levels of melatonin are lowest during the day and highest at
night during sleep(2). The endogenous circadian rhythm is not usually
set exactly to 24 hours but tends to be closer to 25 hours with a wide variation
among individuals(2). An individual's "endogenous clock" is usually
being readjusted on a daily basis by exogenous, environmental cues (zeitgeber,
German for "givers of time"). The strongest environmental cue is light(3),
but social cues and exercise are also factors.
Symptoms of Jet Lag
Symptoms of jet lag can include fatigue, difficulty in sleeping, and lack
of concentration. Mood disturbance, anorexia, and gastrointestinal problems
are also common(4). Jet lag can adversely affect performance of
both cognitive and manual skills, including athletic performance(5).
While nearly all travellers will experience some symptoms with large time
zone shifts, there is considerable individual variation in both severity and
recovery time. The effects are generally worse for eastward travel and with
increasing age(6).
In addition to disruption of the circadian rhythm, stresses related to
travel, such as sleep deprivation and dehydration, can contribute to the symptoms
of jet lag(7).
Recommendations for the Prevention and Management of Jet Lag
To date, there have been few randomized, controlled trials (RCTs) of measures
to prevent and manage jet lag. In the few RCTs that have been performed, there
was no uniform, syndrome-specific scale with which jet lag symptoms were measured.
As a result, the interpretation of these studies and comparisons among studies
are difficult.
Many of the following recommendations are not supported by RCTs or well-performed
cohort studies and therefore fall into the category of grade III quality of
evidence (see Table 1). Recommendations to prevent and
manage jet lag can be grouped under three general headings: before travel,
during travel, and after arrival in the new time zone.
Table 1. Strength and quality of evidence summary(8)
Categories for strength of each recommendation
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Category
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Definition
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A
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Good evidence to support a recommendation of use
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B
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Moderate evidence to support a recommendation of use
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C
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Poor evidence to support a recommendation for or against use
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D
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Moderate evidence to support a recommendation against use
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E
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Good evidence to support a recommendation against use
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Categories for quality of evidence on which recommendations are made
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I
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Evidence from at least one properly designed randomized, controlled
trial
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II
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Evidence from at least one well-designed clinical trial without randomization,
from cohort or case-controlled analytic studies, preferably from more than
one centre, from multiple time series, or from dramatic results in uncontrolled
experiments
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III
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Evidence from opinions of respected authorities on the basis of clinical
experience, descriptive studies, or reports of expert committees
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Before Travel
-
Travellers crossing multiple time zones should be counselled on the likely
occurrence and implications of jet lag(9) (C III).
-
Travellers should be encouraged to be well rested and not sleep deprived
before the start of a long flight(7) (C III).
During Travel
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Travellers should try to maintain adequate hydration by drinking plenty
of fluids, especially water(7) (C III).
-
Travellers should minimize their intake of alcohol- and caffeine-containing
beverages, which can exacerbate dehydration(7) (C III).
-
Eating light meals may be beneficial; however, specific types of foods
(e.g. carbohydrate versus protein) have been suggested but not shown to
lessen the symptoms of jet lag(9) (C111).
-
The timing of meals may help in the adjustment to a new time zone (see
recommendations below under the heading Upon Arrival)(7) (C III).
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Short-acting hypnotics (sleeping pills) may be used on the flight or
for the first few nights upon arrival(10). These drugs have not
been shown to have any effect on resetting the human circadian rhythm(11).
Short-acting hypnotics may impair cognitive and manual skills and should
be used only in consultation with a physician(7) (C III).
Upon Arrival
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The traveller who will be away from home for < 48 to 72 hours may
attempt to stay on "home based" time for sleep and activity, if this is
feasible(7) (C III).
-
For travel > 72 hours, the traveller should attempt immediately upon
arrival to adjust his or her cycle of sleeping, eating, and activity to
that appropriate to the destination(12). This adjustment can
be started during or even before travel, if practical(9) (C III).
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If practical, travellers are well advised to avoid important activities
such as business meetings or competitive sports for >= 48 hours
after arrival(9) (C III).
-
Short-acting hypnotics (sleeping pills) may be used to facilitate sleep
for the first few nights upon arrival(10). They may impair cognitive
and manual skills and should be used only in consultation with a physician(7)
(C III).
-
Caffeine has been used as a stimulant to delay sleep upon arrival in
a new time zone. The benefit of this approach for travellers, if any, is
likely to be modest. Caffeine should not be consumed for several hours before
travellers try to fall asleep(9) (C III).
-
If practical, travellers may consider spending time outside during the
day at their destination, to help with adjustment to the new time zone.
Adequate studies using light manipulation in travellers have not been done(7)
(C III).
Melatonin
In recent years there has been a great deal of interest in the possible
role of exogenous melatonin in the management of jet lag. As noted previously,
endogenous melatonin, secreted by the pineal gland, contributes to the physiologic
regulation of circadian rhythm(1).
Only a small number of randomized, double-blind studies have examined different
regimens of melatonin for the treatment of jet lag, and the results of these
studies have been inconsistent(13-15). The conflicting data may
be partially explained by the lack of a uniform, syndrome-specific scale to
measure jet lag severity.
-
The effect of melatonin on the prevention or modulation of jet lag, if
any, is likely to be small and this drug cannot be recommended for these
purposes at this time(16) (C 1).
-
Well-designed studies with sufficient power are needed to clarify melatonin's
potential role in the management of jet lag.
Melatonin is not licensed in Canada, and its safety has not been established.
Melatonin is sold as a dietary supplement in health food stores in the United
States. The FDA (Food and Drug Administration) does not regulate dietary supplements,
and therefore the purity and potency of melatonin products obtained in the
U.S. cannot be guaranteed.
References
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Minors DS, Waterhouse JM. Circadian rhythms in general. Occup
Med 1990;5:165-82.
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Disorders of chronobiology. In: Kryger MH, Roth T, Dement WC (eds). Principles
and practice of sleep medicine. 3rd ed. Philadelphia: WB
Saunders, 2000:589-614.
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Czeisler CA, Kronauer RE, Allan JS et al. Bright light induction of
strong (type 0) resetting of the human circadian pacemaker. Science
1989;244:1328-33.
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Moore-Ede MC. Jet lag, shift work, and maladaption. News Physiol
Sci 1986;1:156-60.
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Comperatore CA, Krueger GP. Circadian rhythm desynchronosis, jet lag,
shift lag, and coping strategies. Occup Med 1990;5:323-41.
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Monk TH, Buysse DJ, Reynolds CF et al. Inducing jet lag in older people:
adjusting to a 6-hour phase advance in routine. Exp Gerontol 1993;28:119-33.
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Tasman A. Psychiatry. 1st ed. WB Saunders Company,
1997:1233-34.
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MacPherson DW. Evidence-based medicine. CCDR 1994;20:145-47.
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Committee to Advise on Tropical Medicine and Travel. Travel statement
on jet lag. CCDR 1995;21:148-51.
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WHO. International travel and health. Geneva: WHO, 2002
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Turek FW, Van Reeth O. Use of benzodiazepines to manipulate the circadian
clock regulating behavioural and endocrine rhythm. Horm Res 1989;31:59-65.
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Rakel RE. Conn's current therapy 2002. 54th ed. W.B.
Saunders, 2002:155
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Petrie K, Dawson AG, Thompson L et al. A double-blind trial of melatonin
as a treatment for jet lag in international cabin crew. Biol Psychiatry
1993;33:526-30.
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Spitzer RL, Terman M, Williams JBW et al. Jet lag: clinical features,
validation of a new syndrome-specific scale, and lack of response to melatonin
in a randomized, double-blind trial. Am J Psychiatry 1999;156:1392-96.
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Caldwell JL. The use of melatonin: an information paper. Aviat
Space Environ Med 2000;71:238-44.
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Goroll AH. Primary care medicine. 4th ed. Lippincott
Williams & Wilkins, 2000:1192
* |
Members: Dr. B. Ward (Chairperson); H. Birk;
M. Bodie-Collins (Executive Secretary); Dr. H.O. Davies; Dr. M-H Favreau;
Dr. K. Gamble; Dr. S. Kuhn; Dr. A. McCarthy; Dr. P.J. Plourde; Dr. J.R.
Salzman. |
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Liaison Representatives: Dr. R. Birnbaum
(CSIH); L. Cobb (CUSO); Dr. V. Marchessault (NACI); Dr. H. Onyette (CIDS);
Dr. R. Saginur (CPHA). |
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Ex-Officio Representatives: Dr. E. Callary
(HC); Dr. N. Gibson (DND); Dr. P. Kozarsky (CDC); L. Lannin (FAIT); Dr.
M. Lapointe (CIC); Dr. V. Lentini (DND); Dr. P. MacDonald (HC); Dr. M. Parise
(CDC). |
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Member Emeritus: Dr. C.W.L. Jeanes. |
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This statement was prepared by Dr. J.R.
Salzman and approved by CATMAT. |
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