Waking up in the morning tired may be related not to sleep duration but to waking up in the middle of the sleep phase. According to experts, there are two types of sleep phases - deep and shallow sleep. To determine when we should go to bed, we will use the "90-minute principle." Each phase has approximately a duration like this one, which alternates with each other.
Experts believe that a person feels refreshed if he wakes up at the end of any 90-minute phases. Therefore, we need to calculate the bedtime by summing each 90-minute stretches from bedtime to waking time.
According to doctors, one of the leading causes of insomnia is the wrong lifestyle, including going to bed at the wrong time. Also, to overcome insomnia, specialists advise us to refrain from looking at the clock in case of waking up at night.