Our Sleep Calculator is here to help you better understand how each stage of the sleep cycle affects your mental and physical health. Keep reading to learn how to reap the benefits of a good night’s sleep.
Table of contents
What is a sleep cycle?
There are four stages of sleep–Stage 1, 2, 3, & REM sleep. One sleep cycle is made up of all four sleep stages and will run from stage 1 through REM sleep. Typically, we go through 5 full sleep cycles a night. Each stage is responsible for specific functions that are necessary for proper health.
How long is a sleep cycle?
One full sleep cycle, from stage 1 to REM, will last around 90 to 110 minutes.
How many sleep cycles should you get each night?
The CDC recommends that adults get between 7 to 9 hours of sleep each night for optimal health. With one sleep cycle lasting 90 to 110 minutes, this equates to about 5 full sleep cycles a night.
What are the stages of sleep?
There are 4 sleep stages–Stage 1, 2, 3, and REM Sleep. Each stage triggers specific brain and muscle functions.
During stage 1, (also known as “light sleep”) the body is transitioning from a wakeful state to light sleep. Sleepers can wake easily during this stage and may twitch or jerk as they fall asleep. Slow brain waves, called theta waves, occur during stage 1, as well as slow eye movements.
During stage 2, the body has transitioned to full sleep. Breathing begins to slow down and body temperature drops. K complex structures and sleep spindles make it difficult to wake someone during stage 2. These structures help you disconnect from the environment. Most adults typically spend at least 50 percent of the night in stage 2.
During stage 3, (also known as “deep sleep”) the body has transitioned to deep, restorative sleep. Slow delta brain waves begin to clean the brain. Blood pressure and respiratory rates drop during stage 3, and Human Growth Hormone (HGH) works to rebuild muscle tissue. Most sleep talking and sleepwalking takes place during this stage, and it can be difficult to wake up.
Since deep sleep is when the body does most of its physical repair, a mattress that keeps you from shifting due to pressure points matters here — the Amerisleep AS3 uses pressure-relieving foam designed to help reduce the tossing and turning that can cut deep sleep short.
During REM (Rapid Eye Movement) Sleep, (also known as “Paradoxical Sleep), the eyes begin to move quickly from side to side and brain activity increases. Breathing becomes quick and shallow and dreaming begins. This stage is called Paradoxical sleep because your brain is active but your body is paralyzed. Night terrors are also common during REM.
Why is sleep important?
Sleep is vital for proper brain function and muscle recovery. If you don’t get enough sleep, your body will not have the time it needs to repair itself.
Sleep deprivation can make everyday tasks difficult. It can impact cognitive abilities, hand-eye coordination, attention span, and the ability to focus.
Over time, a lack of sleep can also lead to more serious health complications such as type 2 diabetes and heart disease. With proper sleep and a good mattress, you will be more alert, your muscles will recover faster, and you will be able to handle stress more effectively.
How much sleep is recommended per age?
- Newborns (0-3 months): 14-17 hours each day
- Infants (4-11 months): 12-15 hours
- Toddlers (1-2 years): 11-14 hours
- Preschoolers (3-5): 10-13 hours
- School age children (6-13): 9-11 hours
- Teenagers (14-17): 8-10 hours
- Adults (18-64): 7-9 hours
- Older adults (65+): 7-8 hours
Tips for Better Sleep
Aside from a healthy diet and exercise, you can improve your sleep by establishing healthy sleep habits. Below, we include some simple things you can include in your nighttime routine to find adequate rest.
- Establish a set bedtime and wake up time you can stick to
- Avoid caffeine at least 6 hours before bed
- Avoid large meals at least 2 hours before bed
- Reduce exposure to blue light (electronic screens) at least 3 hours before bed
- Destress before bed with a relaxing bath or shower, breathing exercises, or journaling
- Remove stress triggers from your bedroom and keep your sleep space clean
- Keep your bedroom cool, between 60 and 67 degrees
- Reduce light in your bedroom by using blackout curtains, blinds, or eye masks
Related Sleep & Mattress Guides
- Best Mattress (2026 Guide)
- Best Mattress for Side Sleepers
- Best Cooling Mattress
- How Much Sleep Do You Really Need?
FAQs
What time should I go to bed if I wake up at 6 a.m.?
Count backward in 90-minute increments from your wake time. For a 6 a.m. wake-up, ideal bedtimes fall around 8:30 p.m., 10 p.m., 11:30 p.m., or 1 a.m., depending on how many full cycles you want.
Why do I feel more tired after 9 hours of sleep than after 6?
Waking up mid-cycle, especially during deep sleep, tends to cause more grogginess than waking between cycles, even if the mid-cycle wake-up followed more total sleep.
Is it bad to nap during the day?
A short nap of 20 to 30 minutes can support alertness, but longer or later naps can make it harder to fall asleep at night and disrupt your regular sleep cycle.
How accurate is a sleep cycle calculator?
Sleep cycle calculators use a 90-minute average, but actual cycle length varies by person and by night, so results are a helpful estimate rather than an exact science. It may take some experimenting to find what works best!
