My work aims to identify the mechanisms of the non-visual effects of light on the brain and human physiology, such as the sleep-wake cycle, increase in body temperature, heart rate, modulation of brain activity and regulation of melatonin levels. More specifically, the temporal dynamics of these non-visual effects on physiology and their modeling.
Our recent results show that the brain, heart and temperature regulation in humans are simultaneously activated by light within 1 to 5 minutes after exposure, and those with relatively low light levels (Prayag et al., 2019a, Front. Neur.). In addition, it has been shown that melatonin, a hormone that promotes sleep, is extremely sensitive to light, and that very low light levels can disrupt its function (Prayag et al., 2019b, J. Pineal Res.).
These results highlight, in a precise and specific manner, that the effects of light are observed much faster and at much lower levels than previously imagined. Our modeling of these biological responses to light can be a first simple and interpretable tool to estimate the levels of human physiological responses to low intensity light exposures, in a context where our evenings, at home or outside, are increasingly illuminated.
- Melatonin suppression is exquisitely sensitive to light and primarily driven by melanopsin in humans (2019)
- Dynamics of non-visual responses in humans: as fast as lightning? (2019)
- Light modulation of human clocks, wake, and sleep (2019)
- “Circadian Effects”of Light: Elements of Context (2019)