Correct, it’s not magic. It’s biology. Light, mostly natural light, is what controls your daily rhythm and what constantly resets your biological clock to a 24 hours cycle when it’s by default not that good and might range from 23 to 25 hours naturally.

The latter fact is also responsible for natural early birds or natural late risers because those are people with a natural inner clock more leaning to the 23 hour or 25 hour side respectively.

And that’s where things actually get interesting. The majority belongs to the second group. They are also the one most suffering from our modern style of life. Because while the early bird can just start the day a bit slower and can voluntarily go to sleep an hour earlier when his inner clock tells him the day is over (that free time after all), the late risers don’t have that choice. Neither can they just sleep a bit longer matching their “but my 25-hour of day/night are not done yet”-cycle because they have to get to work, nor can they go to bed an hour earlier to get enough sleep because they are simple not tired yet and still in day mode.

And there is exactly one thing that helps those people to not live in a constant state of light sleep deprivation. Earlier sunrises and sunsets to adjust there biological clock to better work with a 24 hours duration. Daylight saving times does the opposite and hurts the portion of the population already badly adjusted to hour modern day cycle (again: they are the majority, too).