If you’re anything like me, you’ve probably indulged in a little bit of late-night revenge bedtime procrastination.
Happily for fellow binge-scrollers, it turns out that the blue light from our phone might not damage our sleep as much as we’d thought ― but unfortunately, the pros still recommend setting a decent bedtime.
In a recent TikTok, Dr. Karan Raj, who’s known for sharing his medical knowledge on the app, said that although there’s no one-size-fits all rule for nodding off, there are some unusually bad times to fall asleep.
He shared a video which stated that staying awake from the hours of 10pm to four in the morning can increase your risk of cancer and cardiovascular disease.
“What time you choose to go to bed can actually affect your sleep quality, but it’s more nuanced than this video implies,” he responded.
This was his advice:
We sleep in 90-minute cycles
The doctor pointed out that our sleep takes place in roughly-hour-and-a-half-long cycles, “during which your brain moves from non-rapid eye movement [REM] to [REM] sleep”.
And while the cycles remain 90-minutes-or-so long, the ratio of non-REM to REM sleep changes as the night goes on. “The early part of your sleep is dominated by the deeper, more restorative non-REM sleep,” he said.
But as we creep into the morning, “you get more of the lighter, dream-infused REM sleep,” he added.
Due to differing body clocks, some will feel sleepy at 11pm while others will only want to kip at 1am. Depending on yours, “there will... be some adaptation by the body to ensure you get enough of the non-REM and REM sleep,” Dr. Raj said.
So, as long as you have a consistent bedtime and waking up time, you should be good, the doctor said. Unless you choose one specific time to fall asleep, that is...
What’s the worst time to fall asleep?
Dr. Raj says that “it doesn’t really matter the exact time you go to bed... with a caveat.”
“Say, for example, you go to bed at three or four am,” he said. “Regardless of your biology, your sleep will be more REM-heavy and you’ll have less of the deeper, non-REM sleep”.
If you’re wondering what effect that can have, the doctor shared that “this can leave you feeling groggy and tired ― that’s why it sucks to be a shift worker with shitty sleep patterns.”
Given a choice, those who can should avoid sleeping at 3-4am, however. Looks like I have to give my late-night self a sterner talking-to...