17th-century English Puritan treatises of practical theology taught their readers an ascetic lifestyle by which they could self-examin and care for both their physical and their spiritual healths. These treatises blend medical and theological perspectives, emphasizing the primacy of theology and offering guidance in the form of what can be called “spiritual regimens”. This article explores what such texts prescribe concerning physiological sleep. Puritan theologians imitate and adapt the style of medical regimens to communicate their casuistical advice on sleeping within a theological framework. Sleep is good but it must be subject to meticulous moderation for it to edify the body and the soul and not become sinful. Physical health – and therefore good sleep – must be sought for because, firstly, it benefits one’s spiritual health, and, secondly, because it enables the individual to better serve God, family, Church, and society. When compared with prescriptions of medical regimens on the one hand and with the portrayals of puritan pastoral biographies on the other, the “spiritual regimens” prove to be more demanding than the former while being less ascetic than the latter.