A lot happens in our bodies while we sleep. We cycle between what's called non-REM (NREM) and REM sleep. We go through four stages in the human sleep cycle, and they occur in order, as follows:
1. Non-REM Sleep Stage 1 (NREM-1)
2. Non-REM Sleep Stage 2 (NREM-2)
3. Non-REM Sleep Stage 3 (NREM-3)
4. REM Sleep (REM)
This cycle repeats four or five times over the course of a night's sleep and is known as the four stages of human sleep. 
NREM vs REM Sleep
REM stands for Rapid Eye Movement because, during parts of REM sleep, our eyes move rapidly in different directions, which doesn't happen during non-REM sleep.
Stages of Sleep: How the Cycle Works
Our body cycles through the four stages of sleep multiple times over the course of the night. The first three stages of sleep are non-REM, followed by a shorter period of REM sleep, and then the cycle starts over again. Most adults go through 4 to 5 complete sleep cycles per night over a 6 to 8 hour period. Many people associate dreams with REM sleep because this is the stage where most dreams occur.
As you can imagine, each sleep stage plays a critical role in our health and recovery, so efficiently cycling through all four stages of sleep throughout the night is key to getting the best sleep ever.
In this post, we're sharing what happens in each stage and the natural ingredients you can use to maximize your sleep in each stage to fall asleep easily, lower your body temperature, sleep deep, and achieve REM to wake refreshed.
Stage 1 Sleep (NREM-1)
The first stage of human sleep is the transition from wakefulness to sleep and is hallmarked by the drop of Alpha (relaxed awake) and Beta (alert Awake) and rise of Theta (light sleep) and Delta (deep sleep). This occurs just after you close your eyes, and is the lightest sleep you experience during the night, so even small disturbances can wake you from this sleep stage. This stage is also called the gateway to sleep. It does not happen at any start of each cycle.
The goal of this stage is to get to sleep fast. Nutrients that help with this are valerian root extract, lemon balm extract, jujube fruit extract, magnolia bark, and hops extract. These natural ingredients all help you transition into sleep mode instead of stirring restlessly, with your mind racing, trying to get to sleep.
This ingredient is especially helpful for people who tend to have an active mind at night.
LEMON BALM EXTRACT
Lemon balm leaves contain chemicals called terpenes and eugenol. Terpenes play a role in the herb's relaxing effects. Eugenol helps to calm muscle spasms and numbs tissues. Various studies show that the combination of lemon balm combined with other calming herbs (such as valerian and hops) helps to reduce anxiety and promote sleep. Another study showed that lemon balm on its own increased mood and significantly increased calmness and alertness.
Stage 2 of Sleep (NREM-2)
During this second stage of human sleep, your brain produces theta brain waves, and your body transitions into a state of deep relaxation where your core temperature and heart rate decrease and muscles relax in preparation for the deepest sleep to come.
It's important to note that core temperature is a circadian process, and core body temperature drops from the beginning of the attempt to sleep till approximately mid sleep (3-4 AM). As sleep deepens from the first attempt of falling asleep, the core body temperature drops, as does the breathing rate and heart rate. With REM sleep the breathing and heart rate changes towards the signals seen during wake.
Sleep spindles occur during this stage, which are periodic bursts of brainwave activity generated in the hippocampus (our brain's short-term information storage site), and are thought to be responsible for transferring memories from the prior day from the hippocampus to a more long term storage site in the brain – the cortex. Sleep spindles are named for the way they look on an EEG reading - a spindle of clustered higher frequency waves.
The time spent in the NREM-2 sleep stage in the first cycle is around 10-25 minutes, and increases per successive cycle. Overall, this sleep stage accounts for about 50% of our sleep.
The nutrients glycine, magnesium, calcium, and omega 3-6-9 work behind the scenes to help you continue to lower your body temperature and prepare for deep sleep. All sleep stages are essential for different reasons, but when you don't make it beyond stage 2 sleep, your sleep quality is poor, and you will never feel well-rested.
These nutrients are especially helpful for people who identify as hot or cold sleepers and could benefit from better regulation of their core body temperature.
Evidence suggests the amino acid glycine helps you fall and stay asleep by lowering your core body temperature. It also may have a calming effect on your brain. Studies show that a glycine-induced lowering of core body temperature supports non-rapid eye movement (REM) sleep NREM sleep.
Magnesium acts as a critical electrolyte that helps with body temperature regulation, allowing it to log more sleep time. Other research shows that magnesium increases the neurotransmitter GABA in the brain, which is responsible for calming your mind and helping you fall asleep.
Calcium is a mineral that helps your brain manufacture the sleep-inducing substance melatonin. Melatonin then helps your body lower its core temperature. If your calcium levels are low, you are likely to experience disturbed sleep patterns, particularly in the REM sleep phase.
Stage 3 Sleep (NREM-3)
During this third stage of human sleep, your brain produces delta brain waves while your blood pressure and breathing slows, your muscles relax further, and your deepest stage of sleep occurs. It is harder to wake up from this stage, and if you do, you'll often be disoriented for a couple of minutes. This stage typically lasts 20-40 minutes. Longer bouts in the first half of sleep, shorter in the latter half. The first one can be easily 45 – 90 minutes, decreasing during any successive cycle.
Research suggest slow-wave NREM3 sleep helps restoration, tissue repair, memory consolidation. For example, it helps your brain detoxify by clearing out beta-amyloid plaque – the same plaque found in dementia and Alzheimer's.
The nutrients L-theanine, L-ornithine, L-arginine, vitamin B6 and potassium help you achieve deep, lasting, relaxing sleep, so you can wake up refreshed and ready to execute tasks all day long – instead of feeling sluggish with brain fog.
L-theanine is an amino acid found naturally in tea leaves and certain species of mushroom. It supports relaxation and sleep by boosting levels of the calming neurotransmitter GABA while, at the same time, reducing "excitatory" chemicals in the brain linked to stress and anxiety.
Research also shows L-theanine can improve the quality of deep slow-wave NREM-3 sleep, not just sleep duration. Studies show L-theanine improves NREM sleep even stronger when combined with GABA.
Vitamin B6 helps your body convert tryptophan into serotonin, a neurotransmitter that helps regulate levels of the sleep hormone melatonin.
Stage 4 Sleep (REM)
During this fourth stage of human sleep, referred to as the REM stage of sleep, your brain becomes more active, and your eyes move rapidly while closed. Your brain produces beta and alpha brain waves similar to when you're awake. Everything in your body remains still (temporarily paralyzed) except for the muscles that support circulation and breathing. Both your breathing and heart rate rise during this stage. Dreams also occur during this stage, and research shows your creative abilities are improved by REM sleep.
The REM Sleep stage typically lasts 10 minutes during the first sleep cycle, then extends with each cycle over the course of the night, lasting up to an hour during the last cycle.
As mentioned earlier, you go through 4 to 5 sleep stage cycles over the course of the night, but with each cycle, you spend less time in the deeper stage three, and more time in REM sleep.
The nutrients Melatonin, 5HTP, GABA, and L-tryptophan help you achieve REM sleep.
Melatonin is a hormone produced in the pineal gland to signal the body when it becomes dark outside, telling the body it's time to sleep. The production of melatonin decreases with age, with a sharp yearly decline after age 30, which likely contributes to increased sleep difficulty with age, as well as to overall susceptibility to disease. Several studies show that melatonin may increase REM sleep.
The GABA produced by neurons in the brain helps control REM sleep timing. Low GABA levels can disrupt or even prevent REM sleep. Evidence shows that the combination of GABA and glycine support REM sleep by "switching off" the specialized cells in the brain that allow muscles to be active, paralyzing the body temporarily, which is required for REM sleep.
5HTP is an amino acid your body produces as a precursor to serotonin. Low serotonin levels are associated with sleep disorders, among other conditions like depression and anxiety. Studies with 5HTP have shown promise with sleep disorders and insomnia, especially increasing REM sleep.
Changes in the Sleep Cycle with Age
As you get older, you sleep more lightly and get less deep sleep. So you spend less time in NREM-3. Aging is also linked to shorter time spans of sleep, although studies show you still need (and should try to get) as much sleep as when you were younger.
REM Sleep Supplement by Healthycell
Healthycell's team of physicians and nutritionists set out to combine all of these ingredients into one extra strength, fast-acting, easy to take natural cherry-flavored gel pack; making it the first and only supplement that supports all 4 phases of sleep.
REM Sleep is a complete sleep solution for research-focused people who are serious about sleep, delivered in a natural MICROGEL instead of a pill.