Time is a relative statement especially hours of the day as the earth rotates. Sleep void of nightmares is so much of a blessing. Some people can cope with few hours of sleep while some others need more hours of sleep. As recommended 4hours of sleep a day can help save your wellbeing and keep you safe. But some factors are responsible for sound sleep which is another topic entirely to delve into. Can you define sound sleep? How do you measure the depth to which you have slept. In phantoms? I guess not. Research is on going. And how closely related sleep and the bigger sleep like the Chinese would say, your answer is as good as mine. As for me I will be measuring the depth of my sound sleep tonight
