If you’ve been knee, you probably have observed the situations following: You got up with 8 hours sleep or even longer than the sleep scientists told you, while you still feel tired, and kept that fatigue throughout the morning even the whole day. And in another case, you woke up refreshing and energetic after a shorter sleep like 6 or even less. You would become confused about this phenomenon, which is against the general conception that getting not enough sleep is the elementary cause of feeling tired after waking up. Actually, there is no wrong about this sense, it is just not the whole picture.

What you didn’t know about of the picture is the secret of sleep cycle.What is sleep cycle? Theoretically, a sleep cycle is a 90 minute cycle which includes 4 stages following:

Stage 1: the beginning of sleep cycle

Stage 2: light sleep

Stage 3: deep sleep

Stage 4: REM sleep - Rapid Eye Movement ( when you dream)

Then you will get back to the beginning stage and keep repeating the cycle. Normally, you will have this cycle four to five times every night.

Among all these 4 parts of sleep cycle, deep sleep would be the most dominant stage on regeneration. During deep sleep, which is also known as slow-wave sleep, you stop thinking in your brain, and you become less responsive to outside stimuli, breathing slows and muscles relax to the point where you barely move, heart rate usually becomes more regular. Many important physiological processes occur during deep sleep: your organs detoxicate, your kidneys clean your blood, and your body replaces cells, heals wounds, and builds muscle tissues as well. You can say that a high quality sleep is mainly about how much deep sleep you get instead of how much you sleep in all.

Therefore, improving your deep sleep will be the key to make your sleep more effective, granting you adequate energy. According to some sleep science, there are some ways to increase your deep sleep:

1.Keep a proper sleep-friendly diet

An unusually low carbohydrate diet consumed over the short term in healthy sleepers promotes an increase in the percentage of deep sleep. Thus you should not intake high carbohydrate food st least 3 hours before sleep. If you feel hungry before bedtime, food with high protein like nuts or eggs would be a much better choice.

2.Play deep-sleep stimulating music or sounds in your bedroom

A recent research shows that the sound whose burst frequency is as same as your brain waves when your brain is in deep sleep will lead your mind to have more of these regenerative delta waves.

3.Gain proper exercise

Undoubtedly, a proper level of exercise does good to many aspects of human’s well-being, deep sleep benefits from it also. The National Institutes of Health recommend 30-minutes exercise each day and 5 times a week.

If deep sleep is about body, then REM is about the brain. REM is when most dreaming happens and your eyes move rapidly in different directions (hence the name). Heart rate increases and your breathing becomes more irregular. REM is a critical stage for emotion regulation and memory, clearing the brain of useless stuff.

Besides improving the effectiveness of sleep by increasing the deep sleep time, whether you wake up in the right time affects on your day-time state primarily. You will feel a disaster when you wake up during the deep sleep. It also gets you grogginess throughout the morning , even the whole day. It has the potential to ruin your work, class and even dating. That’s why you will feel still exhausted even though you slept for 8 hours or more.

To avoid being woken up from deep sleep or REM stages, one simple way is having a sleep time which is Multiple of 90 minutes, but you should add another 15 minutes around for entering the beginning stage of the sleep. While Since the duration different people needs to slip into sleep cycle varies, as well as the sleep cycle, to make it exact, we recommend you to use professional app or device like “sleep time” which can follow and record your sleep track and wake you up at the most right second in the morning .

We are living in a fast-paced era, it seems there is no enough time for you to complete to-do list. In this case, most of us tend to cut out our sleep time. While your body still requires sufficient sleep to regenerate each day to give you sufficient energy for the next day. Check our blog about "How does the human brain function with a lack of sleep?” for more information. It is common that making your sleep effective by increasing your deep sleep and waking up at the right time would be the exact balance point you were seeking for a long time.