Proceedings of the National Academy of Sciences of the United States of America

Strong but varying effects of evening light on the human body clock

Updated

Abstract

The group-level for 50% is 24.60 lux, indicating high sensitivity to evening light.

  • Interindividual differences in sensitivity to evening light may contribute to vulnerability to circadian disruption.
  • Light intensities of 10, 30, and 50 lux led to later melatonin onset by 22, 77, and 109 minutes, respectively.
  • Individual effective dose values varied significantly, ranging from 6 lux in the most sensitive individual to 350 lux in the least sensitive.
  • A 26% coefficient of variation in individual effective doses suggests substantial variability in response to light exposure.
  • The findings imply that the same light environment can affect individuals' circadian systems differently.

Simplified

Key numbers

24.60
Group-Level for
for 50% in the group.
6 of 350
Range of Individual Values
Individual effective doses ranged widely.
109 min
Delay in Onset
Apparent onset at 50 was delayed by this duration.

Full Text

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