The only way to see how much REM sleep you're getting is to measure your brainwaves. An electroencephalogram (or EEG for short) does just that. A head band is placed on your forehead to pick up the signals being sent throughout your brain - this is the home sleep EEG version, real easy to use.
As the most advanced sleep tracker on this list, SleepScore uses sonar technology to measure sleep habits from your nightstand. The app sends sonar waves from your phone to measure your breathing and any sounds, which allow it to track light, deep, and REM sleep and identify when you wake up during the night.
Some sleep trackers estimate REM sleep in addition to deep and light sleep stages by measuring heart rate. Although heart rate and respiration rates are known to vary greatly during sleep, they have a close relationship with each sleep stage since the autonomic nervous system significantly affects both.
Most new wearables also track the sleep stages you cycle through throughout the night. But “in terms of tracking light, deep, and REM sleep, basically all of the devices performed at only a medium level of accuracy,” says Chinoy. Translation: There's only about a 50-percent chance your data is accurate.
Yet, when compared with polysomnography, the Fitbit was largely underestimating deep and REM sleep, missing roughly half of the former and a third of the latter. It also overestimated light sleep. The Fitbit recorded an average of 50 minutes more total sleep than polysomnography, a figure in line with previous studies.
Deep sleep and REM are defined by certain types of brainwaves and physiological states and these devices can estimate these states with about 80% accuracy.
On average you'll go through 3-5 REM cycles per night, with each episode getting longer as the night progresses. The final one may last roughly an hour. For healthy adults, spending 20-25% of your time asleep in the REM stage is a good goal. If you get 7-8 hours of sleep, around 90 minutes of that should be REM.
While you're sleeping, your device tracks the beat-to-beat changes in your heart rate, known as heart rate variability (HRV). These numbers fluctuate as you transition between light sleep, deep sleep, and REM sleep stages.
Watch out for caffeinated drinks such as coffee and drugs such as diet pills and decongestants. Medications such as antidepressants can cause less REM sleep. People who smoke heavily often sleep lightly and have less REM sleep. They may wake up after a few hours because they experience nicotine withdrawal.
While all types of sleep appear to be essential, deep wave sleep could be considered the most essential. If your sleep is restless and non-restorative, you may lack sufficient deep sleep. REM sleep assists memory differently than deep sleep, focusing on social-emotional memories and even salvaging forgotten memories.
REM deprivation increases basal arousal and enhances drive-related behaviors like hyperphagia. It also affects physiological, psychological process as well as neurotransmitter levels. The mechanisms behind these changes are not fully understood.
To see your sleep history on iPhone, open the Health app on iPhone, tap Browse, then tap Sleep. For more details—the average time you spent in each sleep stage, for example—tap Show More Sleep Data.
Unfortunately, being able to calculate the "precise" bedtime to wake up feeling refreshed in the morning, regardless of how long we've slept, is too good to be true, says Dr Sean Cain, of the Monash Institute of Cognitive and Clinical Neurosciences at Monash University.
According to the universally accepted sleep studies, sleep can be divided in 4 stages and 2 categories, namely Rapid Eye Movement (REM) and Non-REM (NREM). The stages are: N1 (NREM): It's the first stage of sleep, where a person is between wakefulness and sleep.
“Your heart rate can vary quite a bit during REM sleep because it reflects the activity level occurring in your dream. If your dream is scary or involves activity such as running, then your heart rate rises as if you were awake,” says Dr.
While both brands offer outstanding, high-quality wearables, Fitbit has more budget-friendly options, superior battery life, and better health and fitness tracking than the Apple Watch. The Apple Watch edges out the Fitbit in terms of accuracy, convenience, and extra features, but it may be too pricey for some users.
We need the most REM sleep as infants and children, when our brains are still developing. Newborn babies spend eight hours in REM sleep each day. By adulthood, we only need an average of two hours of REM sleep each night.
For healthy adults, 20-25% of your total time asleep should be REM sleep. That's where the 90-minute number mentioned above comes from. If you sleep for 7-8 hours, 20% of that equates to roughly an hour-and-a-half, or 90 minutes. However, it's worth noting that the amount of REM sleep we need also declines with age.
Waking up during the deep sleep or REM stages of your cycle can leave you fatigued all day. The best time to wake up is when you are in light sleep. When you wake-up during the light sleep stage you feel more refreshed and energised.
WatchOS 9 can detect REM, core and deep sleep, as well as offer heart health support and prompt you to take meds.
“Many people wake up tired, even with adequate amounts of sleep. This is likely due to insufficient amounts of deep and REM sleep” shares Dr. Ghacibeh. “So while all stages of sleep are essential to overall well-being, deep sleep is considered the most important stage.”