Is it permissible to reduce sleeping hours for the sake of worship if it affects a person's health and productivity?

The people of knowledge disliked excessive sleep because it deadens the heart, burdens the body, wastes time, and leads to heedlessness and laziness. The most beneficial sleep is that which occurs when there is a strong need for it. The appropriate number of sleeping hours varies according to people's circumstances and ages, but it is generally between six and eight hours. Just as excessive sleep is blameworthy, so too does a lack of sleep and fighting it lead to great ailments such as bad temper, deviation of the soul, and destructive illnesses.