[Good Sleep Techniques] Quality sleep is determined in the first 90 minutes! A thorough explanation of the mechanisms of sleep

[Good Sleep Techniques] Quality sleep is determined in the first 90 minutes! A thorough explanation of the mechanisms of sleep

Have you been feeling like you're having trouble falling asleep lately, or that you still feel tired when you wake up in the morning?

It could be a sign that your sleep quality is declining.

In particular, the first 90 minutes after falling asleep is an important time that greatly affects the quality of your sleep that day.

Mastering these "golden 90 minutes" is the key to improving your performance during the day and living a fulfilling life.

[Good Sleep Techniques] Quality sleep is determined in the first 90 minutes! A thorough explanation of the mechanisms of sleep

What is the "golden time" to improve sleep quality?

Our sleep is not just about closing our eyes and resting our bodies.
Two distinct states, deep "non-REM sleep" and dream-inducing "REM sleep," alternate in cycles of approximately 90 minutes.

Of these, non-REM sleep plays the most important role in recovering from mental and physical fatigue.

Both the brain and body are in a state of deep rest, and the first 90 minutes after falling asleep is the "golden time of sleep" when non-REM sleep is at its deepest.

How deeply you sleep during this time will affect your entire sleep cycle, which in turn will have a major impact on your physical condition and mood the next day.

If you end up with shallow sleep during these first 90 minutes, your brain and body will not be able to fully recover from fatigue, and you will likely find yourself in a state where you feel like you haven't slept at all or you feel sleepy no matter how much you sleep.

Quality sleep is not just rest; it is an essential element for our health, improving cognitive functions such as concentration, memory, and judgment during the day, and even maintaining immunity.

[Good Sleep Techniques] Quality sleep is determined in the first 90 minutes! A thorough explanation of the mechanisms of sleep

Why is it hard to fall asleep? Factors that disrupt sleep

Many people have the problem of wanting to get a good night's sleep but not being able to.
Behind this lies a variety of factors unique to modern society.

  • Accumulation of stress
Pressures in everyday life and work, and troubles in relationships keep our minds and bodies in a constant state of tension.

This state of tension gives dominance to the sympathetic nervous system, which excites the body, and hinders the function of the parasympathetic nervous system, which promotes relaxation.

As a result, you may have trouble falling asleep or wake up multiple times during the night.

  • Irregular lifestyle habits
If you don't go to bed and wake up at the same time every day, your body clock will be disrupted and it will be harder for you to feel naturally sleepy.

  • Activities before bed
If you continue to look at a screen such as a smartphone or computer right before going to bed, the blue light will stimulate your brain and prevent you from falling asleep.

Additionally, consuming caffeine or alcohol before bed can significantly reduce the quality of your sleep.

  • Meal times and contents
Eating right before bedtime will make your stomach and intestines more active for digestion and raise your body temperature, which will prevent you from getting a deep sleep.

  • Poor bedroom environment
Light: If your bedroom is too bright or even a little light comes in, the secretion of melatonin, the sleep hormone, is suppressed, making it difficult to fall asleep smoothly.

  • sound
Even minor sounds such as traffic, the sounds of your neighbors' daily life, or the ticking of a clock can disrupt your sleep.

  • Temperature/humidity
If the room temperature is too high or too low, or if the humidity is not appropriate, your body will not feel comfortable, leading to an uncomfortable sleep.

These factors may interact in a complex way to reduce the quality of our sleep.

Reviewing each of these things one by one will be the first step towards better sleep.


[Good Sleep Techniques] Quality sleep is determined in the first 90 minutes! A thorough explanation of the mechanisms of sleep

Steps to get quality sleep

So, what specific measures can be taken to ensure that these important "first 90 minutes" are deep, high-quality sleep?

By paying a little more attention to your daily habits, you can see big changes.

1. Relax your body and mind with a bath

We recommend taking a leisurely soak in a lukewarm bath (about 38-40°C) 1-2 hours before going to bed. Avoid water that is too hot, as it can actually excite your body.

Bathing temporarily raises your body temperature, and then as your body temperature slowly drops, you will naturally feel sleepy.
This drop in body temperature is an important sign that promotes a smooth transition into deep sleep.

② Thoroughly organize your bedroom environment

The quality of your sleep is greatly influenced by the environment in your bedroom. By appealing to your five senses, you can help your body recognize that this is the place to sleep.

③ Light adjustment

An hour before going to bed, gradually reduce the brightness by turning off the lights in the room and using indirect lighting.

Also avoid the blue light from smartphones and tablets to prepare your brain for sleep.

Ideally, it should be completely dark, but if that's not possible, use blackout curtains.

④ Noise countermeasures

Noise is a major disruption to sleep.
A quiet environment is ideal, but if you are bothered by outside noise, it can be effective to use earplugs or play soothing music in the background.

Nature sounds and quiet instrumental music in particular can mask unpleasant sounds and have a calming effect.

⑤ Optimizing temperature and humidity

Maintain a comfortable room temperature of 25-27°C in summer and 18-23°C in winter.
The ideal humidity level is 50-60%. It is important to use air conditioners and humidifiers effectively to prevent discomfort and dryness while sleeping.

⑥Make soothing music your ally

One of the most effective ways to relax your mind and body is to listen to soothing music.
Music is said to directly affect brain waves, inducing alpha and theta waves, which indicate a relaxed state.

In particular, our healing music at Della Co., Ltd. has been developed to support quality sleep.

Music that includes the fluctuating sounds of nature, gentle melodies, and specific frequencies can be expected to have the effect of balancing the autonomic nervous system and giving dominance to the parasympathetic nervous system.

Why we recommend Della's sleep music

Scientifically Based Design

Based on years of research, we have incorporated specific frequencies and rhythms that induce a relaxed brain wave state, aiming to induce a more natural, smooth and comfortable sleep.

Pleasant tones and melodies

The music is composed mainly of calm, non-stimulating tones so as not to disturb your sleep.
Avoid sudden loud or sharp sounds and use slow melodies to provide comfort and calm the mind and body.

Supports natural sleep onset

It provides the perfect sounds to release the tension of the day and help your body and brain transition smoothly into deep non-REM sleep. The gentle guidance to help you drift off to sleep supports a quality sleep experience.



Staff recommendation! You can listen to it♪


The Ultimate Sleep CD / Rumors Ambient Project
価格：¥1,980


Why not start today by adopting good sleep habits that focus on the "first 90 minutes" and maximize your performance tomorrow?

Quality sleep is the best investment you can make in living a healthy and energetic life.



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