Proper sleep endows an individual with nourishment, strength, virility, knowledge, longevity and happiness. On the other hand, improper sleep causes misery, emaciation, sterility and even early death. Untimely and excessive sleep as well as prolonged vigil take away both happiness and longevity.

It is not advisable to sleep during the day in seasons other than summer. Doing so causes vitiation of kapha and pitta. Obese people who are used to unctuous substances, those with a pitta constitution, those suffering from diseases due to vitiation of kapha and those suffering from artificial poisoning (which happens when substances are incompatible are mixed and consumed either deliberately or inadvertently; honey in hot water can act as a poison) should never sleep during the day. This could lead to liver problems, heaviness of the body, fever, loss of Digestive power, Oedema, Anorexia, Nausea, Urticaria, Eruption, Abscess, Drowsiness, Coughing, Diseases of the throat, Impairment of the memory and intelligence, Obstruction of the circulatory channels of the body and weakness of sensory or motor organs.

Sleeping during the day in all seasons is permitted for those who are exhausted by singing, studying, alcoholic drinks, sex, elimination therapy, carrying heavy weights, walking long distances; those suffering from diarrhea, colic pain, dyspnea, insanity; those who are too old, too young, weak and emaciated; those injured by fall and assault; those exhausted by a journey, vigil, anger, grief and fear. In summer, nights become shorter and vata gets aggravated in the body due to absorption of fluid because of perspiration. Therefore, during this season, sleep during the day is allowed for all.