We often hear claims such as : I need only 4 hours of sleep every day to get rejuvenated.
Such claims are not wrong, as various sleep studies in the past do claim that the duration of “sufficient Sleep” or “Adequate sleep’ varies from person to person. A person may feel fresh after 6 hours of sleep, while another may feel sleepy even after after 8 hours of uninterrupted sleep. Thus no one must blame the other for sleeping long.
That said, another study says that Sleep is cummulative. What does this mean?
This means that any sleep deficiency sums up and shows up later. For instance if a person in a habit of sleeping 6 hours of day, it gets only 5 hours of sleep for six days, then on the 7th day he/she will be almost feeling as if he/she has NOT slept for one full day.
This also means that, if a person in a habit of sleeping 6 hours a day, sleeps for seven hours for the next 6 days, then on the 7th day he/she will have a day sleep surplus of one full day. That’s why researchers advice you to sleep surplus, before any journey to make up for any sleep deficit during the journey or tour.
The researchers advice on sleeping surplus before any journey or tour because a human body and mind with surplus sleep is better able to cope with any unfavourable conditions the body and mind may face during the journey or tour.