I seem to hear from a variety of people that they struggle to fall asleep at night; but the difficult to fall asleep sounds like an evolutionary downside. Even as hunter-gatherers, being able to sleep whenever and wherever sounds like it would be an advantage.
Is it a recent product of modern times and people didn’t actually struggle with it a while back? In which case, what of modern life is causing this? If not, what is the evolutionary advantage of not falling asleep easily?
I remember from the book “Why We Sleep” that our sleep cycle takes cues from both light and temperature levels throughout the day, which we isolated ourselves from in modern times. The day doesn’t end after sundown anymore thanks to lightbulbs, and many of us live at a constant temperature due to AC. That’s two clues of “night is near, prep to sleep” that we no longer receive. Maybe our ancestors had an easier time due to more consistent clues?