|
|
Seasonal Variation in Human Illumination Exposure at Two Different Latitudes
Roger J. Cole
Department of Psychiatry, University of California, San Diego, CA 92093-0667, Synchrony Applied Health Sciences, Del Mar, CA 92014-3805
Daniel F. Kripke
Department of Psychiatry, University of California, San Diego, CA 92093-0667
Joyce Wisbey
Mayo Clinic Sleep Disorders Center, Rochester, MN 55905
William J. Mason
Department of Psychiatry, University of California, San Diego, CA 92093-0667
William Gruen
Ambulatory Monitoring, Inc., Ardsley, NY 10502
Peter J. Hauri
Mayo Clinic Sleep Disorders Center, Rochester, MN 55905
Silvia Juarez
Department of Psychiatry, University of California, San Diego, CA 92093-0667
The authors measured ambient illumination exposure in healthy volun teers in San Diego, California (latitude 32° 43' N, n = 30), and Rochester, Minne sota (latitude 44° 1'N, n = 24), during each of the four quarters of the year, which were centered on the solstices and equinoxes. Subjects wore photosensors on their wrists and lapels (or foreheads while in bed) 24 h per day for an average of 5-6 days per quarter. The maximum of the two illumination readings was stored each minute. Annual average time spent per day in outdoor illumination ( 1000 lux) was significantly higher in San Diego than it was in Rochester (p <.04). Daily durations of illumination at or exceeding thresholds of 1,10,100,1000, and 10,000 lux were highly seasonal in the sample as a whole (p < .01 at 1 lux, p < .0001 at other thresholds). Seasonal variation in outdoor illumination was far more pronounced in Rochester than it was in San Diego (interaction p < .001) but remained significant in San Diego (p  .03). Seasonal variation in indoor illumi nation was generally similar in the two cities. The median Rochester subject experienced illumination 1000 lux for 2 h 23 min per day during summer and 23 min per day during winter. The corresponding times in San Diego were 2 h 10 min and 1 h 20 min. Neither age nor gender predicted illumination duration at any level. Both season and geographic location strongly influenced human illumination exposure, and behavior (choice of indoor vs. outdoor environment) was the most important mediating factor.
Key Words: illumination • light • exposure • season • latitude • human
Journal of Biological Rhythms, Vol. 10, No. 4,
324-334 (1995)
DOI: 10.1177/074873049501000406
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
R. G Stevens
Light-at-night, circadian disruption and breast cancer: assessment of existing evidence
Int. J. Epidemiol.,
April 23, 2009;
(2009)
dyp178v2.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
G. Goulet, V. Mongrain, C. Desrosiers, J. Paquet, and M. Dumont
Daily Light Exposure in Morning-Type and Evening-Type Individuals
J Biol Rhythms,
April 1, 2007;
22(2):
151 - 158.
[Abstract]
[PDF]
|
|
|
|
|
|
|
A. Kawinska, M. Dumont, B. Selmaoui, J. Paquet, and J. Carrier
Are Modifications of Melatonin Circadian Rhythm in the Middle Years of Life Related to Habitual Patterns of Light Exposure?
J Biol Rhythms,
October 1, 2005;
20(5):
451 - 460.
[Abstract]
[PDF]
|
|
|
|
|
|
|
E. B. Klerman, J. M. Zeitzer, J. F. Duffy, S. B. S. Khalsa, and C. A. Czeisler
Absence of an Increase in the Duration of the Circadian Melatonin Secretory Episode in Totally Blind Human Subjects
J. Clin. Endocrinol. Metab.,
July 1, 2001;
86(7):
3166 - 3170.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. E. Matthews, P. S. Freedson, J. R. Hebert, E. J. Stanek III, P. A. Merriam, M. C. Rosal, C. B. Ebbeling, and I. S. Ockene
Seasonal Variation in Household, Occupational, and Leisure Time Physical Activity: Longitudinal Analyses from the Seasonal Variation of Blood Cholesterol Study
Am. J. Epidemiol.,
January 15, 2001;
153(2):
172 - 183.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. G. M. Beersma, K. Spoelstra, and S. Daan
Accuracy of Human Circadian Entrainment under Natural Light Conditions: Model Simulations
J Biol Rhythms,
December 1, 1999;
14(6):
525 - 532.
[Abstract]
[PDF]
|
|
|
|
|
|
|
C. I. Eastman, M. A. Young, L. F. Fogg, L. Liu, and P. M. Meaden
Bright Light Treatment of Winter Depression: A Placebo-Controlled Trial
Arch Gen Psychiatry,
October 1, 1998;
55(10):
883 - 889.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
M. E. Jewett, D. W. Rimmer, J. F. Duffy, E. B. Klerman, R. E. Kronauer, and C. A. Czeisler
Human circadian pacemaker is sensitive to light throughout subjective day without evidence of transients
Am J Physiol Regulatory Integrative Comp Physiol,
November 1, 1997;
273(5):
R1800 - R1809.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
