Sleep and wakefulness are factors that contribute greatly to our state of health. As long as a person is awake, he is involved in some form of exertion which creates heat and burns energy. In turn, this energy needs to be replenished. To some extent, the body can replenish this energy through digesting food. However, the most natural and simple way for the body to retain and restore energy is through sleeping which is vitally necessary for the body.
This can be understood through the example of a person who eats and drinks, but does not sleep at all. Despite eating and drinking, he will eventually become totally exhausted and overcome by fatigue. Hence, it is clear that there is no replacement for sleep.
Conversely, if a person sleeps too much, his body will become weak and lazy and his muscles will become stiff. This is commonly seen in people who are bedridden. Their bodies become stiff and lose their elasticity, and if their posture is not changed, bed sores, etc., begin to set in.
It is thus necessary for one to strike a balance between sleeping and remaining awake. In this regard, it is important to realize that different people require different amounts of sleep.
People who have more moisture in their bodies require more sleep, as this moisture creates lethargy and tiredness in the body. Therefore, a person who is of a phlegmatic temperament (cold and moist) will require up to eight hours of sleep. A person of a sanguineous temperament (hot and moist) will require six to seven hours of sleep. A person of a bilious temperament (hot and dry) or a melancholic temperament (cold and dry) will require a minimum of five to six hours of sleep a day.
From the above, it is clear that people who are drier in temperament require less sleep than people who are moister in temperament.
Adapted and summarized from “Your Health” by Moulana Hakeem Jalil Muhammad Pandor (An Nasihah vol. 117)