Several articles on the subject suggest that another hormone, oxytocin, affects one's sleep-wake cycle.  Oxytocin , often referred to as the "love hormone," is a neuropeptide produced in the hypothalamus and released by the pituitary gland. "People in romantic relationships tend to have higher levels of oxytocin, a hormone associated with pair bonding," Madeline Sprajcer, a psychology lecturer at Australia's Central Queensland University, told Newsweek, adding that "It also appears that oxytocin can have a positive impact on our sleep." Oxytocin has been shown to make people fall asleep more quickly and rest more efficiently, with an increase in restorative REM [rapid eye movement] sleep episodes. This so-called love hormone is often released during sexual activity, particularly during orgasm. Oxytocin can be released by simply being in the presence of a romantic partner to whom you are strongly attached, Sprajcer said. However, Newsweek's article highlighted that "feeling sleepy around your partner is not a foolproof indicator of a happy relationship." Emre Selçuk, an associate professor of psychology at Turkey's Sabanci University, told Newsweek that "the calm and quiescent state that partners instill almost borders boredom," underscoring that "the feeling that there is nothing else to do or to share with your partner can make you sleepy in their company." In an article  titled "Why do I get sleepy around my partner? A therapist's take," NOCD therapist April Kilduff explained that "Studies have found that people in relationships tend to have higher levels of the hormone oxytocin than those who are single": This hormone, which is sometimes referred to as the "bonding" or "love" hormone, is important for building connections between human beings. Our brains naturally release more oxytocin after being touched, or through positive interactions with others. So it's no surprise that people in good relationships tend to have higher levels. Oxytocin is also thought to all