Nocturnal penile tumescence
Nocturnal penile tumescence (NPT) is a spontaneous erection of the penis during sleep or when waking up. Along with nocturnal clitoral tumescence, it is also known as sleep-related erection. (Colloquially, the term morning wood (or less commonly, morning glory) is also used,[1] although this is more commonly used to refer specifically to an erection beginning during sleep and persisting into the period just after waking.) Men without physiological erectile dysfunction or severe depression[2] experience nocturnal penile tumescence, usually three to five times during a period of sleep, typically during rapid eye movement sleep.[3] Nocturnal penile tumescence is believed to contribute to penile health.[4]
Mechanism
The cause of nocturnal penile tumescence is not known with certainty. In a wakeful state, in the presence of mechanical stimulation with or without an
The nerves that control one's ability to have a reflex erection are located in the
In a study published in 1972,[11] during puberty, the average tumescence time per night was 159 min; average REM sleep time was 137 min. Average simultaneous REM sleep and penile tumescence per night was 102 min. Study subjects averaged 6.85 tumescence episodes/night, and, of these, 5.15 occurred during a REM sleep period. Tumescence episodes during REM averaged 30.8 min in duration, whereas episodes which occurred when no REM was present averaged 11.75 min. Study subjects had at least four REM periods per night and at least three tumescence episodes.
In another study of healthy older people published in 1988, frequency and duration of nocturnal penile tumescence decreased progressively with age independent of variations in sleep. In contrast to younger age groups, the majority of those above age 60 did not have full sleep erections even though they and their partners reported regular intercourse.[12]
Unlike physiological penile tumescence, sleep-related painful erections (SRPE) and stuttering priapism (SP) are much rarer pathological erections, resulting in poor sleep and daytime tiredness, and long term cardiovascular morbidity.[13] SRPE is a rare parasomnia consisting of nocturnal penile tumescence accompanied by pain that awakens the individual.[14] It occurs predominantly during REM sleep, without an apparent underlying illness or penile anatomic abnormalities. On the contrary, stuttering priapism can occur spontaneously at any time of the day, but more commonly so during REM sleep. SP is a subtype of ischemic priapism that is characterized by recurrent, self-limiting, painful erections that often require maneuvers (compression, cold packs or a cold shower, voiding, or exercise, etc.) to aid detumescence. In ischemic priapism, most of the penis is hard; however, the glans penis is not. Much rarer priapism is secondary to blunt trauma to the perineum or penis, with laceration of the cavernous artery, which can generate an arterial-lacunar fistula resulting in a high blood flow state, hence the tumescence. Tumescence lasting for more than four hours is a medical emergency.[15] At the time being, no treatment consensus for SRPE has been established. Baclofen tablets taken before sleep is the most commonly used medication, having a tolerable profile of adverse effects.[14]
Diagnostic value
The existence and predictability of nocturnal
Nocturnal penile tumescence testing
Regularly, those who experience erectile dysfunction are given a nocturnal penile tumescence test, usually over a three-day period. Such a test detects the presence of an erection occurring during sleep using either:
- a small portable computer connected to two bands placed around the shaft of the penis which records penile tumescence,
- a band of paper tape with perforations (similar to coil postage stamps) that is fit snugly around the shaft of the penis and will break at the perforations during penile tumescence.
The goal of nocturnal penile tumescence testing is to determine whether one can experience an erection while sleeping after reporting that they are unable to experience an erection while awake. On average, one has 3–5 episodes of NPT each night, and each episode lasts 30–60 minutes, although the duration is reduced with advanced age.[16] If one does obtain an erection while sleeping, but cannot obtain one while awake, a psychological cause or a medication side effect is usually suspected. Otherwise, if one does not obtain an erection in either state, a physiological cause is usually suspected.
See also
- Nocturnal emission
- Priapism
- Sleep sex
- Swelling
- Tumescence
References
- S2CID 26939007.
- S2CID 24315629.
- ^ a b c Felson S (7 November 2020). "Tests for Erection Problems". WebMD, Inc. Retrieved 2007-03-03.
- ^ Alexander B (October 2010). "Why guys rise and, well, rise in the morning?". The Body Odd. NBC News.
- ^ "SCI Fact Sheets - Spinal Cord Injury Model System". Heersink School of Medicine. The University of Alabama at Birmingham (UAB).
- PMID 16135662.
- PMID 12559293.
- ^ Klebine P, Lindsey L (May 2007). "Sexual Function for Men with Spinal Cord Injury". Spinal Cord Injury Information Network. University of Alabama at Birmingham. Archived from the original on 2013-09-06. Retrieved 2011-12-17.
- ^ "Nervous system control of the male reproductive system". Spinal Hub. Retrieved 2018-01-09.
- ^ Beale S (Aug 2016). "Why Do Men Get Erections in the Morning". IFL Science. Retrieved 2016-12-03.
- S2CID 10758883.
- PMID 3418036.
- S2CID 236993535.
- ^ PMID 31844522.
- PMID 28027457.
- ISBN 978-0-07-159331-1.
Further reading
- Knight J (November 2016). The Complete Guide to Fertility Awareness. Routledge. ISBN 978-1138790100.
External links
- The dictionary definition of Wikisaurus:morning wood at Wiktionary