Vol.21: Not getting an erection in the morning is a warning sign of ED: Part 2

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【Not getting an erection in the morning is a warning sign of ED: Part 2】


As I previously explained, the terrestrial Mammalia repeats non-REM sleep (deep sleep) and REM sleep (comparatively shallow sleep) during sleeping. As for the healthy men, the phenomenon which is called “nocturnal penile tumescence” occurs during REM sleep. This erection phenomenon which occurs approximately 4-8 times is caused due to the seesaw relationship between two kinds of autonomic nerve systems (sympathetic and parasympathetic nerve), and, in fact, this “getting erection when waking up” can be an important factor to evaluate the initial-symptom of ED, as well as the quality and severity of ED.
“Not getting an erection in the morning” is a warning signal of ED: Part 1
Why does the “nocturnal penile tumescence” occur?
It is known that the period of having nocturnal penile tumescence is taken up to 20-40% of the sleeping hours. However, why does it occur at the time when it has nothing to do with reproduction? There was a German doctor (Ohlmeyer et al.) who reported the fact in 1944 that a penis erection phenomenon was seen among young and middle aged men averaging 24.5-minutes in duration in the interval of 84.5 minutes during the time they were asleep. Since then, the study about this has been going on for more than 60 years, but the physiologic meaning is still completely obscure. There are various hypotheses such as that it occurs because of the stress alleviation which was received during daytime, or it’s a bloodstream training for the purpose of preventing blockage of the cavernous-body-of-penis and the corpus cavernosum of the urethra, or preventing night enuresis (bed-wetting), or the sign that the bladder has become full and so on. However none of these were scientifically proved as of 2010.
Let’s see the factor which has an influence on the “nocturnal penile tumescence”
The mechanism of the “nocturnal penile tumescence” is still unknown, but any men who are healthy are supposed to experience it. So let’s see the factors which give influence to the “nocturnal penile tumescence” a little further. These ones as below are nominated and known as the factors which can decrease or weaken the nocturnal penile tumescence.
(1)The change of quality and time of sleep which accompanies aging
(2) Sleep disorder (sleep apnea syndrome, alcoholic sleep disorder and insomnia due to the anxiety and depression).
(3)Due to the intake of anti depression and antihypertensive medication (especially with tricyclic antidepressant drug)
(4) Decrease of Male hormone secretion (testosterone)
(5) Diabetic peripheral neuropathies disorder
(6) High blood pressure, diabetes and vascular endothelial disorder (arteriosclerosis) caused by hyperlipidemia
(7) blood circulation disorder caused by thrombotic disease
(8) Penile fault caused by trauma and so on
The decrease of the frequency and hardness when getting “nocturnal penile tumescence” is closely related to the symptom of ED, too. If the “nocturnal penile tumescence” is caused by the factors of the above (3)-(8), it’s not too much to say that having no “nocturnal penile tumescence” = a sign of developing ED. (ED: getting insufficient erection when having sex)
On the other hand, because the above (1) and (2) are the influence which relates to the quality and amount of sleep, so they don’t always relate to ED. I’ll mention this later, but when not getting enough sleep (mainly REM sleep), means less opportunity for the nocturnal penile tumescence to occur. In this case, ED is possible to be caused indirectly, but not directly, which means we can’t say that having no “nocturnal penile tumescence” = a sign of developing ED.
As I previously mentioned in the column “Not getting an erection in the morning” is a warning signal of ED, and the symptom of ED for men who get sufficient “nocturnal penile tumescence” is more likely not to be organicus ED but ideogenetic ED on which we can say that the ED curatives should work better.
On the contrary, when not getting “nocturnal penile tumescence”, if the cause could be either (1) or (2), it has no direct relation to ED and if the cause could be (3) or (8), it can be said that it’s a direct sign of ED.
Lastly, to tell you one more thing, because the “nocturnal penile tumescence” occurs in about 20 to 40% of the whole sleeping time even for healthy man, morning erection only occurs once every 3 to 5 nights on average. If it doesn’t happen every night, please don’t worry. If you have a question or any inquiry, don’t hesitate to visit our clinic for a consultation with our doctor.

Vol.9: Not getting an erection in the morning is a warning signal of ED


【Supervisor of this article】

Ken Takemori, MD. An anesthesiologist and Director of Shibuya 3rd Block Clinic.


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