Have you ever thought why people often wake up when there is light? Even when the morning and the sun shines and illuminates our rooms we will automatically wake up. The existence of this light turns out to affect our body like the presence of light that helps plants photosynthesize.
Turning off the lights when going to sleep is often recommended by many people. This is because when we sleep the body will produce the melatonin hormone so that sleep becomes more sound. The melatonin hormone in the body works by slowing down our heart rate, blood pressure, and breathing.
Whereas the presence of light will actually cause the cortisol hormone to increase in the body. In contrast to the melatonin hormone, the cortisol hormone works to balance energy in the body, causing heart rate, blood pressure and breathing to be higher. Therefore it is not surprising that if the light appears in the morning or afternoon and illuminates our bedroom, we usually will wake up.
This is the reason why you need to turn off any source of lights at night. Leaving your bedroom dark is one way for the body to produce melatonin which then makes you sleep well at night.