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Chronobiology and Sleep Laboratory


The Chronobiology and Sleep Laboratory (CSL) conducts research on circadian rhythms and sleep patterns. The circadian (about a day) system plays an important role in regulating cognitive performance and sleep-wake timing. Circadian rhythms of behavior and physiology are normally synchronized with the rising and setting of the sun. In response to shift work or jet lag, however, circadian rhythms can become misaligned with the sleep-wake cycle and/or solar day. This results in sleep disturbances and impaired neurobehavioral performance. Additionally, many individuals are habitually exposed to sleep deprivation due to lifestyle choices, environmental pressures, or sleep disorders.

The CSL aims to 1) understand the impact of circadian desynchrony and sleep deficiency on performance and health, and 2) develop approaches for optimizing circadian entrainment and improving sleep behavior. There are three major research themes in the CSL:



The CSL conducts both laboratory and field studies. The CSL routinely uses the following research methods:
  • Polysomnography for sleep staging and for assessing wake-dependent changes in the electroencephalogram
  • Constant routine procedure for assessing circadian rhythms
  • Evaluation of circadian phase markers including core body temperature, melatonin, and cortisol
  • Eye-tracking for ocular-based measures of drowsiness
  • Pupillometry for evaluating pupillary responses to light
  • Neurobehavioral tests for assessing sustained attention, working memory, processing speed, hand-eye coordination, and mood/fatigue
  • Actigraphy monitoring of sleep-wake patterns in field studies



The CSL conducts research that has broad implications for health and safety. Our work has therefore been supported by diverse sources of funding including medical research grants, military contracts, and industry partnerships. Many of our research initiatives were supported by the Duke-NUS Signature Research Program funded by the Agency for Science, Technology, and Research, and the Ministry of Health, Singapore. Below we highlight additional sources of support, both past and present, by research topic:

  • Non-visual photoreception: National Medical Research Council, Singapore; and the Singapore National Eye Center Health Research Endowment Fund.
  • Circadian rhythms and metabolism: SingHealth Foundation, Singapore.
  • Shift work and cognitive vulnerability: Defense Advanced Research Projects Agency (DARPA), USA; Defense Science Technology Agency, Singapore; Republic of Singapore Navy; Defense Science Organization (DSO) National Laboratories, Singapore.
  • Sleep insufficiency in adolescents: National Research Foundation, Singapore; Far East Organization
  • Sleep deprivation and alcohol: Ministry of Education, Singapore; Defense Science Technology Agency, Singapore