The Journal of Neuroscience, 2000, 20:RC66:1-5
RAPID COMMUNICATION
Chronic Jet Lag Produces Cognitive Deficits
Kwangwook
Cho1, 4,
A.
Ennaceur1,
Jon C.
Cole1, 2, and
Chang Kook
Suh3
1 Department of Psychology, University of Durham,
Durham, DH1 3LE, United Kingdom, 2 Department of
Psychology, University of Liverpool, Liverpool, L69 7ZA United Kingdom,
3 Department of Biophysics and Physiology, College of
Medicine, Inha University, Incheon, 402-751 Republic of Korea,
and 4 Medical Research Council Centre for Synaptic
Plasticity, Department of Anatomy, Medical School, University of
Bristol, Bristol, BS8 1TD, United Kingdom
Traveling across time zones causes disruption to the normal
circadian rhythms and social schedules because of travelers' shift in
time. As the endogenous circadian timing system adapts slowly to new
time cues, the phase relationship between biological rhythms and
external time cues are out of synchronization for a period of time.
This disturbance of circadian rhythms has been shown to impair physical
and psychological health (Winget et al., 1984). To test the effects of
repeated jet lag on mental abilities, airline cabin crew were compared
with ground crew. Salivary cortisol was used as a physiological marker
for circadian disruption. The cabin crew group, who had a history of
repeated jet lag, had significantly higher salivary cortisol levels in
an average working day. In addition, this elevated level of cortisol
was only seen in the same subjects when the cabin crew were on
transmeridian flights but not domestic flights. Cabin crew also
exhibited cognitive deficits, possibly in working memory, that became
apparent after several years of chronic disruption of circadian rhythms.
Key words:
jet lag; cortisol; stress; human subject; cognition; memory
Copyright © 2000 Society for Neuroscience 0270-6474/00/$05.00/0