Quantal melatonin suppression by exposure to low intensity light in man

Prediction Model of Light-induced Melatonin Suppression

“…Verification of mathematical models 3.1 Existing reports used in the verification and verification results The mathematical models to predict the melatonin suppression value in cases with pupil reflex and the actual experimental results were compared. For the actual experimental results in cases with pupil reflex, the results of McIntyre et al 30) , who used fluorescent lamps that simulate natural light, and Aoki et al 31) , who used white fluorescent lamps, were used. Table 2 shows the details of the conditions and results for each experiment.…”

“…Within the marks that have circadian rhythms, such as sleep and waking, rectal temperature, and cortisol, the secretion rhythm of melatonin is said to be the least effected by the actions other than those of the biological clock in SCN. Because there are basic findings regarding multiple factors of the effects of light on melatonin secretion, such as action spectrum 22)23) , the dose response relation with light intensity 22)23) , duration of exposure to light 30) 31) , pupil reflex 32) , and age 33) , they are considered appropriate marks when modeling the influence of light on living organisms. In many reports that covered the influence of light on melatonin secretion, mydriatics are used and pupil diameter does not change in the experiment so the conditions differ from general environments which includes pupil reflex.…”

Lighting as a Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment

“…In comparison, typical horizontal light levels in buildings are 300 to 500 lux, providing about 60 to 100 lux at occupants' eyes [14]. Later studies showed that with careful control, several hundred lux of white light-which is still relatively bright-incident upon subjects' eyes could suppress melatonin [15][16][17][18]. Similarly, bright light has been shown to cause short-term increases in body temperature, and even to temporarily increase feelings of wakefulness and alertness [19].…”

“…When we consider that outdoor daylight levels regularly exceed 10,000 lux, and that this cycle has been responsible for maintaining circadian entrainment for millions of years, it should not be surprising that the human circadian system requires significantly higher quantities of light to maintain entrainment or shift circadian rhythms [12,[15][16][17][18], compared to what the visual system needs to function. In comparison, indoor light levels-except close to windows-are relatively low [20]; while these are more than sufficient for visual performance, they often fall below the threshold for influencing the human circadian system (see Figure 1).…”

“…The duration of light exposure needed to suppress melatonin in humans, on the other hand, is much longer. Studies from the literature [12,15,16] show that suppression of melatonin content in the bloodstream in humans starts approximately 10 minutes after the initiation of bright light exposure.…”