Some young men wrote in to say that their penises were erect all night long, which made them very fearful and worried about suffering from abnormal penile erection disorder, and asked for “help”. To clarify this issue, it is important to introduce the physiology of nocturnal penile erection in men. In the normal night word sleep, each man’s penis undergoes the physiological process of erection – weakness – erection – weakness again, which is medically known as penile erection at night, everyone has it. Generally speaking, nocturnal erections occur 4-6 times per night in young men, lasting 20-30 minutes each time, with a total erection of up to about two and a half hours. As we age, the number and duration of erections will gradually decrease. Nocturnal erection of the penis is a spontaneous physiological phenomenon during sleep and does not depend on the subjective will of the individual. After understanding the physiological phenomenon of nocturnal erection, it is easy to explain the so-called “all-night erection” concern. It turns out that because these young men have sexual associations before falling asleep to make the penis in an erect state, the penis is soft during sleep and they are not aware of it, and when they wake up in the morning because they are holding urine, the penis is in an erect state, so they have come up with the wrong concept of erect penis all night long. Obviously, this concern is completely unnecessary. Researchers through a large number of social surveys and laboratory studies concluded that: men’s erection during sleep at night has nothing to do with the frequency and quality of recent sex, in addition, when the bladder is full of urine need to urinate or nocturnal sex dreams, etc. can also cause an erection, which is more obviously felt at this time, but this does not account for a large percentage.