How Does The Sleep Cycle App Work

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The Sleep Cycle app optimizes your morning alarm for when you're the furthest out of your REM cycle.
The app finds the perfect moment within a specified time frame for your alarm.
I use the Sleep Cycle app every day and it's completely changed how grumpy I am in the morning.
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When it comes to my sleep habits, I'm pretty lucky: Once I'm out, I am OUT. I can't make it through a late-night social gathering without visibly nodding off at 10:30 p.m. and I recently got the soundest sleep of my life in an Airbnb room with an empty, absolutely cursed Victorian baby crib in the corner. Name the place and I will conk out.

However, this also means that waking me up when I'm not ready is akin to nudging a hibernating bear. I won't just wake up groggy and annoyed — I'll look at the person who woke me up (or just my phone) like a hiker with a flash camera.

Which is why I rely so, so heavily on Sleep Cycle, an app that records you while you sleep (sounds creepy, I'll explain!) to wake you up at the best possible moment within a 30-minute time frame.

When I want to wake up at absolute-latest 7:30 a.m., the app will wake me up sometime between 7:00 and 7:30 based on when my sleep phase is lightest.

To figure that out, I place my phone on my nightstand so the app can record me all through the night and listen to when I'm moving around more. If I'm tossing and turning at 7:10, the alarm will go off then rather than 7:30, even though I'm technically still asleep. (R.E.M., the deepest sleep stage, is when your body becomes immobile, so you definitely don't want to be woken up then!)

It can sound really finicky, needing to be woken up at the exact right time, but it makes such a huge impact on my life. To me, it feels as drastic as being woken up by someone lightly drawing the curtains instead of yelling through a megaphone.

Beyond the day-to-day benefits, Sleep Cycle will show me my full week's recap, so I can notice when I've had multiple nights in a row of only getting six hours of sleep (and help me immediately understand why I'm so cranky).

It's also taught me that getting at least seven hours of sleep doesn't mean hopping into bed at 11 p.m. and waking up at 6 a.m. — I have to factor in the time it takes to actually fall asleep, which can take up to 30 minutes or an hour (especially if, like me, you're up tapping through TikToks until 11:45 for no reason).

I use the free version of Sleep Cycle, which comes with all of the features above. But I've also tried Premium ($6.49 per month; $40 for the year), which is great if you could use special features to help you fall asleep or figure out why you struggle to.

One Premium feature I liked was tracking different factors, like alcohol or exercise, to see how much of an impact they have on my sleep. The results were predictable (jogging is great! Alcohol, not so much.) but it was still enlightening to see such a direct correlation between margaritas and morning grumpiness.

The only downside I've experienced is that I share a bed with my partner, and sometimes he'll rustle around before I do, triggering the alarm (and subsequent glares from me). But with the amount of healthy, consistent sleep I get from this app, I can manage the occasional rude awakening.

Julia is the education and personal development editor on the Insider Reviews team. Since October 2020, she's written about a popular Harvard persuasive writing course, a free UPenn course that explains the science behind COVID-19 vaccines, and a bestselling self-help book seen all over Twitter. She's also organized and edited a series on how to get unstuck during the pandemic as well as what to do when you get rejected from grad, medical, or law school. Through her work as a sex and relationships editor at Cosmopolitan and BuzzFeed, as well as a freelance lifestyle reporter, Julia learned that she loves interviewing experts and putting together stories that inspire people to make small yet effective changes in their lives. Julia is passionate about accessible, affordable education and is living proof that e-learning has the potential to make career transitions more attainable: During quarantine, she completed a five-month Coursera MasterTrack certificate program in Instructional Design from the University of Illinois while starting her role at Insider. You can say hi to Julia at jpugachevsky@insider.com or shoot her a DM on Twitter or Instagram (she is @jaypugz on both). Learn more about how our team of experts tests and reviews products at Insider here. Learn more about how we review educational and personal development products.