Light visor treatment for jet lag after westward travel across six time zones.
BACKGROUND
The aim of this field study was to evaluate the efficacy of a light treatment for jet lag, using a head-mounted light visor, following a westward flight across six time zones.


METHODS
There were 20 subjects who were exposed to bright white light (3000 lux) or dim red light (10 lux) for 3 h on the first two evenings after a flight from Zurich to New York. Salivary dim light melatonin onset (DLMO), assessed 2 d before and 2 d after the flight, provided a measure of circadian phase. Sleep was recorded by actigraphy, while post-flight performance testing and subjective scales provided additional indices of jet lag severity.


RESULTS
The DLMO measurements showed a larger phase delay in the bright light than in the dim light group (2.59 h vs. 1.58 h, p < 0.02). There was no overall difference in sleep efficiency (SE) between the two groups, but a significant Group x Night interaction reflected a small increase across the first two post-flight nights in the bright light group, and a small decrease in the dim light group. Reaction time on one of two performance tests was consistently faster in the dim light group, but was unrelated to circadian phase or to prior sleep. There were no major group differences in subjective sleep quality, daytime sleepiness, jet lag severity, or mood.


CONCLUSIONS
This is the first full-scale study to show that bright light treatment can accelerate circadian reentrainment following transmeridian travel. However, the effect on reentrainment rate was modest, and was not accompanied by any improvement in sleep, performance, or subjective assessments of jet lag symptoms.
Boulos
Ziad
Z
New York State Psychiatric Institute and Department of Psychiatry, Columbia University, New York 10032, USA. zab1@columbia.edu
Macchi
M Mila
MM
Stürchler
Matius P
MP
Stewart
Karen T
KT
Brainard
George C
GC
Suhner
Andrea
A
Wallace
Gordon
G
Steffen
Robert
R
D000328:Adult; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D020179:Jet Lag Syndrome / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008550:Melatonin / Q000032:analysis; D010789:Phototherapy; D011597:Psychomotor Performance; D012463:Saliva / Q000737:chemistry; D012894:Sleep Stages
D008550:Melatonin