Sleep Cycles Are Like a Roller Coaster
As adults, our sleep follows cycles that include brief awakenings throughout the night.
Each sleep cycle lasts about 90 minutes. We typically begin with lighter sleep before transitioning into deeper stages and then rising again into rapid eye movement (REM) sleep—the stage often linked to vivid dreaming.
If we sleep well, most of our deep sleep occurs in the first half of the night, while REM sleep is more common in the second half.
Adults usually experience five or six sleep cycles per night, and it is completely normal to wake up briefly at the end of each one.
This means we might wake up around five times during the night.
These awakenings tend to increase with age and can still be considered healthy. If you don’t remember them, that’s perfectly fine—they are often very short.
What Defines a Good Night’s Sleep?
You often hear that adults need between seven and nine hours of sleep per night.
However, good sleep is about more than just duration—it’s also about quality.
For most people, good sleep means:
- Falling asleep within about 30 minutes of going to bed
- Sleeping without prolonged awakenings
- Waking up feeling refreshed and ready for the day
Understanding your sleep patterns can help identify and adjust behaviors that negatively affect sleep, such as bedtime routines and sleep environment.
Sleep disorders are common, but if sleep issues persist over a long period, consulting a doctor may be necessary.
The Health Consequences of Poor Sleep
- Short sleep duration is linked to obesity in adults
- Poor sleep quality and shortened sleep are associated with a higher risk of type 2 diabetes
- Lack of sleep increases the risk of cardiovascular disease
- Sleep problems are linked to a higher risk of early death
- Shift workers experience more sleep issues compared to those with regular daytime jobs
- Psychological sleep therapy is as effective as sleeping pills
This article is based on information from Pensionist, Ugeskiftet, Sundhedsstyrelsen og Sceince Alert.