Deep sleep: how many hours are ideal for full regeneration? Find out what a healthy proportion is and what you can do if you're tired due to shallow sleep!
The quantity of sleep alone does not guarantee that we wake up truly refreshed. It can happen that we sleep for 7-8 hours, yet still feel tired and exhausted in the morning. One of the most common reasons for this is that our body does not spend enough time in the deep sleep phase, which is the most important period for physical and mental regeneration.
Sleep is a complex biological process in which different phases alternate. If these superficial sleep stages become predominant, the body's regeneration will not be complete, even if we spend enough time in bed. In this article, we will explain what deep sleep means, how much is considered healthy, what are the signs of its deficiency, and how we can promote more restful nights.
What does deep sleep mean in practice?
Quality sleep is not a single continuous state, but consists of several consecutive sleep cycles. A cycle lasts approximately 90 minutes and usually repeats 4-6 times during a night.
Most of our sleep is spent in the so-called NREM phase. The first two stages of this are light sleep, while the third stage is deep sleep.
During this time, brain waves slow down, heart rate and breathing become regular, muscles completely relax, and the body expends the least possible energy on wakeful functions.
In practice, we can experience this as:
- our body is completely relaxed;
- we wake up less often at night;
- we feel fresher and more energetic in the morning.
If we have less deep sleep temporarily due to a stressful period, it is a natural phenomenon. However, if this persists for months, it may indicate a chronic decline in sleep quality. In such cases, daytime fatigue, irritability, and impaired concentration are common.
How many hours of deep sleep? This is the healthy and ideal amount!
Many people primarily monitor the total hours spent sleeping, but it is at least as important how much of that time is spent in actual deep sleep.
How much deep sleep is ideal?
For healthy adults, the ideal proportion of deep sleep is approximately 15-25% of the total sleep time. This is enough for the body to carry out its most important regenerative processes.
Expressed in numbers – How much deep sleep is good?
If we sleep 7-8 hours daily, healthy deep sleep is usually 1.5-2 hours.
If we regularly spend nearly 9 hours sleeping, then approximately 2 hours of deep sleep can be considered ideal.
It is important to know that it is not a goal, nor would it be healthy, to spend the entire night in this phase.
The brain also needs lighter sleep stages and REM sleep, as these support, among other things, memory function, emotional processing, and learning processes.
What happens in our body during deep sleep hours?
During deep sleep, the body performs almost complete maintenance.
Although the brain does not "shut down," its slowed activity allows it to remove metabolic byproducts accumulated during the day. This is particularly important for memory, concentration, and long-term brain health.
Meanwhile, the production of growth hormone increases in the body, which supports the regeneration of muscles, bones, and connective tissues. The balance of melatonin and cortisol is also most favorable at this time, contributing to the maintenance of the body's natural biological rhythm.
The immune system also works most effectively then. Cell renewal accelerates, while the utilization of vitamins and minerals consumed during the day can also be more favorable.
Many people are familiar with the feeling of "I'm sleepy but can't fall asleep." This is often due to chronic stress. In such cases, high cortisol levels keep the nervous system in a state of readiness, making it harder to fall asleep, sleep becomes more superficial, and the body has difficulty reaching the truly regenerative deep sleep stage.
Symptoms and causes of insufficient deep sleep – Why does the duration decrease?
If the duration of deep sleep consistently falls below the healthy level, its signs soon appear. The most characteristic symptom is that you wake up in the morning as if you hadn't rested at all, even though you slept long enough. In addition, daytime fatigue, impaired concentration, slower thinking, and irritability are common.
The most common triggers
Mental overload: Chronic stress and constantly racing thoughts make it difficult to relax. The body remains in a state of readiness, making it harder to enter the deep sleep phase.
Caffeine and bad habits: Late afternoon coffee, evening energy drinks, a heavy dinner, or using phones before bed can all worsen sleep quality. The blue light from screens reduces melatonin production, which can delay falling asleep and make sleep more superficial.
Health problems: Sleep apnea is one of the most common causes that unconsciously interrupts deep sleep. Breathing pauses cause tiny micro-awakenings that we often don't remember, yet they significantly impair nighttime regeneration.
Tips for increasing deep sleep time
If truly restful sleep doesn't come, it's not worth forcing it. Instead, cultivate habits that help the body relax naturally.
- Pay attention to caffeine! Consume your last coffee preferably 6-8 hours before bedtime.
- Take a digital break! Put away your phone, tablet, and laptop at least an hour before bedtime to allow melatonin to be produced undisturbed.
- Breathe consciously! A few minutes of slow, deep breathing helps reduce stress and calm the nervous system.
- Don't toss and turn for hours! If you can't fall asleep after about 20 minutes, get up for a short while, read or listen to calming music, then only lie back down when you feel sleepy again.
A regular routine, a bedroom at the right temperature, and daily exercise can also contribute to longer and more restful deep sleep.
The role of physical comfort: How does a mattress support the deep phase?
Restful sleep doesn't just depend on your evening routine! It's at least as important that your body receives adequate support throughout the night.
If the mattress is too firm or too soft, it doesn't properly follow the contours of your body, which can lead to pressure points at the shoulders and hips. In such cases, the body instinctively tosses and turns to relieve these areas.
These small movements often cause micro-awakenings that interrupt deep sleep without you consciously waking up. As a result, we feel tired in the morning, even if we slept long enough.
A suitable mattress, on the other hand, evenly supports the spine, reduces pressure points, and helps the body remain in the deep sleep stage, which is most important for regeneration, for longer periods.
For peaceful nights, you need not only proper sleep habits but also a well-chosen mattress. If you want to reduce tossing and turning at night and create a more comfortable sleeping environment, explore our stress-reducing mattresses, or choose ergonomic mattresses that provide proper spinal support.
If you're not sure which mattress best suits your sleep habits, visit one of our Yatas Bedding showrooms! Our expert colleagues will provide personalized advice to help you find the mattress that will contribute to more restful, deeper sleep in the long term.
