How Waking Up Later Affects Your Brain
Depending on the situation, waking up an hour later than usual might be a bit stressful. If you overslept and are now late for work, you'll probably experience a rush of stress-induced adrenaline as you throw off the covers and race to get ready. But as far as your sleep schedule goes, sleeping in that extra hour can have an even greater impact on your brain, as well as your overall health.
"Research shows that the timing of sleep may be just as important as how many hours we sleep," Rose MacDowell, a sleep expert and chief research officer at Sleepopolis, tells Bustle. So while you might quickly forget the panic that ensued when your alarm didn't go off in time, that extra hour of sleep can create a ripple effect, especially if you keep doing it.
"Sleeping late can lower the sleep drive and make falling asleep the next night more difficult," MacDowell says. When it comes time to wind down and get ready for bed, you'll find that you have more energy than usual, and you'll likely end up staying awake later as a result. This can throw off the next night and the next, and it can be tough to reset your brain and get back on track.
"Sleeping an extra hour can also lower sleep efficiency, which can cause similar effects to sleep deprivation," MacDowell says says. "Sleep efficiency is the percentage of time spent asleep while in bed. Sleep is considered efficient when at least 85% of time in bed is spent asleep, and inefficient when less than 85% is spent asleep. Sleeping late can reduce sleep efficiency because time in bed increases and the circadian rhythm is disrupted [...] Numerous studies show that consistent sleeping and waking schedules are important for keeping the circadian rhythm regulated."
The reason why you're waking up an hour later can also impact how you feel mentally. "If your sleep was interrupted several times during the night, for example, your brain may not be as sharp as usual with a decrease in cognitive ability and in attention span," Dr. Steven Reisman, who is board-certified in internal medicine, tells Bustle. "It may adversely affect memory," which is why you might feel groggy and out of it, or possibly make silly mistakes in school or at work the next day.
While waking up late on occasion probably won't have a major impact on your brain, ongoing disrupted sleep can cause problems over time. "There may be a buildup of amyloid protein in the brain which has been linked to Alzheimer’s disease," Reisman says. So even though it may be tempting to go to bed and wake up at different times each night, it's best to stick to a schedule as often as possible.
"It is advisable to wake up the same time each day because if one gets into a regular routine with a satisfying amount of sleep you will likely feel more energized during the day," Reisman says. "The body's circadian rhythm or internal clock helps dictate when you are tired and awake and it is guided by variables such as light exposure and mealtime. Once you have a regular ‘rhythm’ this will help in more restful and restorative sleep."
In order to avoid these negative side effects, "go to bed and wake up at the same time, even on weekends," MacDowell says. "Reduce your exposure to light at night, particularly blue light from TVs and electronics. Try to go to bed earlier, and resist the urge to sleep in or alter your sleep schedule." By waking up at the same time every day, you'll be doing your brain a huge favor, as well as your overall health.
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Fenichel, M. (2019). Sleep Loss Found to Exacerbate Spread of Toxic Protein Associated With Alzheimer’s Disease. Psychiatric News, 54(8). doi: 10.1176/appi.pn.2019.4b27
Rose MacDowell, sleep expert and chief research officer at Sleepopolis
Dr. Steven Reisman, specialist with New York Cardiac Diagnostic Center