“While all the stages of sleep are important to the cycle, stage 3 is the deepest, most restful sleep. During this stage, your body releases hormones that help repair muscles, bones and tissues, and your brain works on consolidating your memories,” says Dr. Ghacibeh.
These four sleep stages are called non-rapid eye movement (non-REM) sleep, and its most prominent feature is the slow-wave (stage IV) sleep. It is most difficult to awaken people from slow-wave sleep; hence it is considered to be the deepest stage of sleep.
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 is often considered the most important sleep stage, but light sleep is the first step to getting a healthy night's rest. It's part of the complete sleep cycle, and though it may sound like it won't yield restfulness, it's actually quite the opposite.
“We have a lot of distractions to keep us busy, and that's another reason people aren't getting enough sleep - maybe people just aren't prioritising it.” The survey found 37 per cent of those polled had the worst sleep of their life between the ages of 25 to 54.
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.
These include three stages of non-rapid eye movement (NREM) sleep, which make up about 75% to 80% of the night, and one stage of rapid eye movement (REM) sleep, which makes up the remaining 20% to 25%.
Sleep stages
In general, deep sleep (slow wave sleep) decreases with age in the adult population. During nocturnal sleep, the proportion of non-rapid eye movement sleep (NREM) stage 1 and stage 2 increases with age, and the proportion of slow-wave sleep and REM sleep decreases with age2,11 (see Figure 1).
Insomnia in children can begin at any time, from infancy through adolescence, and in some cases can develop into a long-term problem. Symptoms can include: bedtime refusal and struggles going to bed.
Averaging less than 7.5 hours of sleep, Gen Z is expected to perform at the highest levels with the least amount of energy.
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. Very hot or cold temperatures can disrupt REM sleep.
Some people with insomnia experience changes in their sleep cycles and, as a result, may have more stage 1 sleep and less deep sleep. Stress and aging can also reduce levels of deep sleep. Additionally, people with conditions such as schizophrenia and Alzheimer's disease experience less slow wave sleep.
You fall asleep soon after getting into bed, within 30 minutes or less. You typically sleep straight through the night, waking up no more than once per night. You're able to sleep the recommended amount of hours for your age group. You fall back asleep within 20 minutes if you do wake up.
He says, “thanks to foot elevation simultaneously performed with a relaxed back, your blood flows smoother within the body which triggers sleep faster than usual. This body position redistributes the blood on your feet to other parts of the body, promoting better relaxation and physical comfort.”
If you aren't feeling rested when you wake up, despite getting to sleep at least 8 hours prior, then it might not be the quantity of your sleep that's the problem. It could be your sleep quality that needs some attention. The amount of sleep you get is important, but equally important is the quality of that sleep.
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.
There is no set number of hours of sleep that qualifies someone as having insomnia because each person has different sleep needs. Generally, adults are recommended to get 7 hours of sleep each night.