I believe that words are meaningful. According to the explanatory dictionary of V. I. Dahl: “usually the evening is counted from 6 or 7 pm to midnight,” that is, from 18:00 or 19:00 to 00:00. The question refers to "sleep" in the evening, and not "go to bed", which means that a person should not be in a dream in the interval written earlier. There are several explanations for this, which we will consider using an example of the likely consequences:
I would like to write about the well-known "value of sleep", which says that the period from 19:00 to 20:00 is equal to 7 hours of sleep, 20: 00-21: 00 - 6 o'clock, and so on, only if the author of this theory was not a folk healer, and it would be scientifically proven. Therefore, even moving away from this, a person has 6 hours in the evening to sleep. I am sure that most of the people after that will have difficulty falling asleep again, so that the first consequence will be night vigor and problems with subsequent falling asleep. Let me clarify that we are not considering people who work the night shift, sleep during the day, etc.
Let's now consider the option when a person continues to go through his evening marathon almost without interruptions at night, that is, go to bed in the evening and wake up morning / afternoon. He will probably have a sleepiness, and as a result - weakness throughout the body and apathy. This is more likely to apply to people who go to bed before 21:00 and get up after 9:00, but each organism is unique and each person has their own sleep rate, so it is impossible to create an ideal formula for everyone.
Well, my grandmother said so too. More precisely, you cannot sleep at sunset. It seems like you wake up with a headache, tired and sleepy. I checked that everything is fine.