How Being Woken Up Mid-Sleep Cycle Affects You

by JR Thorpe

If you've ever been awakened suddenly by an alarm from a blissful night's rest and wondered if it's broken something in your brain, you're not alone. Quite a lot of scientific attention has been devoted to the proper way to wake people up, and what unnatural "awakenings" actually do to the body and the brain. It may surprise you to know that not all the results are negative; but the new sleep hygiene trend towards "natural" waking, using products that track your sleep and then gradually increase the light in your room so that you drift awake, comes overwhelmingly from this science. Being suddenly woken up mid-sleep cycle just isn't great for you.

Intriguingly, the notion of a full, solid nine hours of sleep without a break is a modern invention. In the medieval period, particularly in Northern winters where nights could last for 14 hours or longer, it seems to have been common to have two "sleeps," with a break of an hour or so in the middle filled with socializing, food, bathroom breaks, and whatever else (ahem). Scientific studies appear to indicate that, when exposed to natural light and darkness patterns, we fall back into this pattern, without any impact on wakefulness or attention during the day. So take the idea of "natural" nine-hour sleep cycles with a pinch of salt; it's been created by modern living conditions rather than real sleep-need.

Next time your kid/partner/cat leaps on your head suddenly and scares you awake, you can lecture them with the many different ways that might ruin your health. And then pull your covers over your head and go back to sleep.

1. You Might Experience "Sleep Drunkenness"

There's a very particular term for the sensation of grogginess, poor reaction time, and general fog that goes with being awakened suddenly mid-cycle, rather than drifting awake naturally: sleep drunkenness, or confusional arousal. Stanford University has reported that sleep drunkenness, brought on by sudden awakening from a nap or deeper sleep, affected around 15.2 percent of 16,000 people surveyed over a year, and that it could last for a while, frequently longer than five minutes.

This follows up findings that interrupted sleep, or awakening during a natural cycle, is deeply problematic for awareness and cognition. A 2014 study from Tel Aviv University found that just one night of interrupted sleep or startling wake-ups was enough to create serious confusion and irritation the next day, and to impact negatively on participants' job performance. The scientists found that interrupted sleep had the same poor consequences for cognition as only getting four hours of sleep a night. Essentially, our brains react very poorly to the idea of being blared out of their rest. Bad news, since most of us use alarms to wake up that often interrupt us mid-sleep cycle.

2. Your Self-Image Worsens

It turns out that being wakened suddenly from the rapid eye movement (REM), stage of sleep, which is associated with increased brain activity and dreaming, may actually cause significant mood problems. The Boston School Of Medicine published a study in 2009 that found that both genders "rate themselves less positively" if they're roused from REM sleep, and that women seemed particularly affected. If they were awakened during REM sleep, both genders rated themselves as pretty terrible on a personality-traits test, and tended to remember worse memories. We're not entirely sure what's happening with this, but Harvard Health points out that REM sleep is particularly involved with memory creation and regulation, so waking during that may be an interference in some kind of emotional balancing during sleep. We'll keep you posted.

3. You Might Be Better At Solving Problems

If you're struggling with creative block, it may be a good idea to somehow program something to wake you up during an REM period in your sleep cycle. Weirdly enough, science has discovered that people wakened during these times in their cycle performed 32 percent better on creative tasks and solving anagrams than when they were woken up during other bits of the sleep cycle. What in hell is going on here?

The scientists behind that anagram-solving test, which was published in 2002, argued that REM sleep is associated with creative processes and abstract reasoning with increased strength of weak associations in cognitive networks"; in other words, the brain is primed during REM sleep to problem-solve and construct connections from abstract stuff. So being woken suddenly from that period of sleep and immediately given tests meant that you carried over the same advantages from your brain's creative fervor. But it's not likely that the impact lasts very long, and as sudden awakenings also seem to also be linked to sleep drunkenness, your alarm clock won't actually solve many problems.

4. Your Blood Pressure Skyrockets

A 2005 study from the Japanese National Institute Of Industrial Health confirmed the instincts of everybody who has ever loathed their alarm with a passion: It seems to be bad for your cardiovascular health to be woken suddenly rather than rousing yourself naturally, at least among the elderly. The study looked at the heart rates and blood pressure of older people during and after an afternoon nap. If they were allowed to wake up naturally, their blood pressure and heart rate naturally climbed to a more "awake" level on their own; if they were awakened by something else, both measures suddenly rocketed, placing a lot of stress on the heart.

The natural rise in blood pressure as we wake up is actually the reason why the morning is such a high-risk time for strokes and heart attacks. But it seems as if a sudden jolt may actually shock our cardiovascular system in an unnatural way.

All the more reason you might want to consider investing in a smart alarm clock or sleep tracker that wakes you up at the right point in your sleep cycle.

Images: Danil Nevsky/Stocksy, Giphy