Sleep plays a pivotal role in the regulation of autonomic functions such as heart rate, body temperature and blood pressure. It also influences endocrine functions, including the secretion of pituitary hormones, leptin and ghrelin, as well as energy homeostasis. In non-rapid eye movement (NREM) sleep, autonomic functioning is relatively stable with a parasympathetic dominance, whereas autonomic activity is considerably variable in REM sleep. Here, we review the regulatory role of sleep on autonomic functioning in REM and NREM sleep. We also review the role of endocrine hormones, i.e., the secretion patterns of hormones that are influenced by sleep-wake homeostasis and circadian rhythm variably. Additionally, we discuss the effect of sleep curtailment on the risk of developing metabolic diseases such as diabetes and obesity.