Virtual Caffeine for Android

The goal of this app is to make people less sleepy when they have to be attentive, just like a virtual portion of caffeine. It is most effective in natural dark periods.

The app is based on the realization that light intensity and, most important, spectral composition regulate the circadian clock of vertebrates and therefore melatonin production. Melatonin is an essential hormone which mediates not only the sleep-wake- but almost every physiological or behavioral rhythm in mammals. Normally, its concentration is high at night and low during the day.

To shift the mammalian biological clock, light duration should be of longer duration, at least 30 seconds and the intensity should be between 0,1 and 100 lux (mammals are more sensitive to twilight intensities than to full sunlight to set their circadian clock).

Studies demonstrate that brief light with an intensity of 1lux can shift the circadian clock by 1-2 hours. If we optimize the spectral output of the light, what is exactly what we have done for you in this app, we get an even greater effect. The here emitted light correlates with the human spectral sensitivity peak which has been found in the blue light at ca. 460nm (see figure 1). As you can see, the spectral effect is not to underestimate.

Like previously mentioned, the agency of this app is greater in natural dark periods. But also in bright periods the exposure to the blue light of our app can make you fitter. The reason is that in contrast to natural sun light, our configured light is adapted to the spectral sensitivity peak of humans and therefore more effective in suppressing melatonin production.

Studies demonstrate that the effectivity of our app depend on the person using it; e.g. lens density changes with age leading to a reduced transmission of short wavelength light (like blue light) in older persons. Besides, there might also be an impact of eye color: melatonin suppression was found to be less affected in dark-eyed Asians than in light-eyed Caucasians. However, this could also be an effect of ethnicity.