Morning comes, the alarm rings, and you hit the snooze button hoping for a few more precious Zzz’s. Maybe you hit the snooze button a second time. And no worries about being late because you planned for the added time. Do those extra Zzz’s really provide additional quality sleep? There is a downside to the snooze button.
We typically focus on the amount of sleep needed, and this is clearly important. The National Sleep Foundation recommends 7-9 hours of sleep for adults. Infants, toddlers and preteens need more sleep to support development and growth. Babies actually spend more than half their time sleeping during this period of tremendous development, especially for the brain. Older adults need 7-8 hours of sleep each night.
But there is more to sleep than the quantity, or number of hours, you get. Sleep quality is equally, if not more important. Sleep quality – how well you sleep – is defined as one’s satisfaction of the sleep experience, including sleep initiation, maintenance and quantity, and feeling refreshed upon wakening.
Do you really feel refreshed after hitting the snooze button one or more times? There is a downside to the snooze button. That is because sleep is not uniform and hitting the snooze button may put you in a non-restorative state of sleep. High-quality rest requires multiple rounds of the sleep cycle – composed of four different sleep stages – during the night. Each stage plays a different role in allowing the body and mind to restore and repair.
Typically, a person goes through four to six sleep cycles through the night, the first of which is the shortest, from 70-100 minutes, while later cycles range from 90-120 minutes. How much time spent in each sleep stage also changes through the night. The four sleep stages include one for rapid eye movement (REM) and three that are non-REM (NREM) sleep, each based on distinct patterns of brain activity. 1-3
NREM sleep is composed of the first three stages.
- Stage 1 consists of the initial five minutes during which a person dozes off, where you may experience twitches as your body and brain activities begin to slow. It is during this stage that it is easiest to wake someone.
- A person typically spends half their sleep time in stage 2, during which body temperature drops, muscles relax, breathing, brain activity and heart rate slow. Eye movement stops and brain waves show a new pattern. During the initial cycle, stage 2 lasts 10-25 minutes and increases during the night.
- Stage 3 is known as deep sleep, during which it is difficult to wake someone. The body relaxes further and breathing, brain activity and heart rate slow down even further. Brain activity is characterized by delta waves, and stage 3 is therefore also known as delta- or slow-wave sleep (SWS). Stage 3 is critical to restorative sleep, allowing for recovery and growth, also for bolstering the immune system and other key processes. Deep sleep also contributes to cognitive function, for example insightful thinking, creativity and memory. Most of the first half of the night is spent in deep sleep. During early sleep cycles, stage 3 typically lasts 20-40 minutes and gets shorter through the night, replaced by REM sleep.