But I get nocturnal erections…

[seekonk]

…why then can’t they even happen when I try to jerk off, never mind sex?

There seems to be something about being awake that doesn’t agree with me.

[Old Guy]

Even after using pills and injections until they failed I would get occasional night time erections. As soon as I woke up enough to do anything with it, it would be shrunk to nothing. Depressing. About three days before my implant I woke up with one.

[Simbarn]

…why then can’t they even happen when I try to jerk off, never mind sex?

There seems to be something about being awake that doesn’t agree with me.

Nocturnal erections are now considered to occur due to the very strong inhibitory mechanism in the penis being almost switched off for a brief period during REM sleep. That is the constant stimulation from NE nerves signalling smooth muscle in the erectile tissues to stay contracted, which occurs during the waking hours, driven by the locus coeruleus area in our brain. If there are defects in the venous occlusive mechanism in the penis, that is, its ability to hold blood or stimulate this ability to hold blood in the erectile tissues, this inhibitory mechanism will have more power maintaining the penis in a flaccid state. During REM sleep, this powerful inhibitory mechanism in the penis is greatly reduced and hormones such as testosterone which are circulating through the penis stimulate the erectile process to occur with ease, without the interruption from norepinephrine (NE). During sleep testosterone levels are also building to the highest peak of the day, which must also encourage this phenomenon.
So even a defective penis, can still have a reasonable erection during these times. However, as soon as we wake and sympathetic action in our body kicks into action, erections will be much more difficult to achieve in a defective penis.
I have also mentioned many times here, that there is ample scientific evidence that sympathetic activity in the penis increases as we age, this can occur more so in some individuals given lifestyle and genetics. Sympathetic activity in the penis itself, is what keeps the penis in a flaccid state. There are other additional mechanisms which ensure the penis stays flaccid during our waking hours, but NE is the main driver.

When we are young for example, in our teens, the forces which enable an erection to occur, which disengage or fight against the inhibitory mechanism are strong and working optimally. This is why teenage males get strong erections with only a sexual thought or the slightest touch in the genital region and many times these erections will not subside easily. As males age this pro-erectile mechanism loses strength and the opposite occurs with the inhibitory mechanism. This is why older men who do not have ED, may need more stimulation to get and maintain an erection and don’t seem to notice spontaneous erections anymore.

I hope the above helps you understand what could be occurring with regard to your nocturnal erections.

[tonyareias]

NE (Norepinephrine) - Erection inhibitor
ACh (Acetylcholine) - Erection activator

Penile smooth muscle relaxation

-NE
+ACh

Penile smooth muscle contraction

+NE
-ACh

[seekonk]

So the presence of nocturnal erections is meaningless for whether ED can improve?

[ftwabeck3533]

So the presence of nocturnal erections is meaningless for whether ED can improve?

I believe you have made an accurate statement.

I'm well-read on the topic of EF (my more positive outlook), but a layman nonetheless. All the anatomical systems required for an erection are explained here (https://www.youtube.com/watch?v=33m9pN_vAI4).

It would seem a nocturnal erection would be a good sign that the systems are working, and probably is a good sign. At my advanced age (66) and loss of EF due to robotic prostatectomy, I obtain some level of an erection while sleeping. Can I translate that into an erection sufficient for penetration of my wife's vagina? No. I require an injection of trimix for that very satisfying activity.

[Simbarn]

So the presence of nocturnal erections is meaningless for whether ED can improve?

No, it’s not as black and white as that. It could depend on the suspected etiology of your ED and the quality and frequency of your nocturnal erections, as these can still occur but be subpar.
For example, very low testosterone can cause nocturnal erections to stop occurring or be weak and it can also cause day time ED. If this low T is corrected early before other comorbidities develop in the penis, both of these issues will be improved.
Also, if very strong nocturnal erections are occurring and the physician cannot find anything physiologically wrong with the penis, but the patient has ED, it can be suspected that a psychological cause may be the culprit.

Sometimes the presence or lack of nocturnal erections helps the doctor determine the cause of your ED, it can narrow down the list of possible causes or defects it may have.

The presence of nocturnal erections in an individual who has ED, does not rule out a physiological cause of that ED as the severity of the physical dysfunction may be at an early to mid stage whereby nocturnal erections can still occur without the inhibition of NE.
CVOD may be occurring due to oxidative stress in the erectile tissues, thus a slow decline in endothelial health and smooth muscle content begins, which gradually makes erections more difficult to achieve in the presence of NE inhibition.

[RoninRiff]

You presented a compelling explanation of some possible mechanisms behind ED, Simbarn. Thank you for doing that. This is a more nuanced explanation I don't see discussed much amidst all the outdated and oversimplified talking points about what causes ED. I don't think clinicians really fully understand this disorder yet. There's got to be more to it than the same old uninspired dross repeated online that fails to explain the cause of ED in a significant number of cases outside of simple arterial insufficiency, etc. Even the concept of "venous leak" is highly theoretic and only derived from indirect evidence that does not point to any specific known etiology. I've long suspected there may be some imbalance between sympathetic and parasympathetic mechanisms at play. The causes of ED are likely multifactorial but the potential role of the autonomic nervous system is very interesting. I would be interested to read more about this. Do you have any good references that you would point to find some more original thinking on this matter?

[Alan810]

I’m by no means an expert on the subject of ED…only a victim of it for many years. In my humble opinion, the cause is partially due to its feeding on itself. ED occurs at one time for one reason or another and we become concerned about it. This leads to obsession, worry and anxiety - and the harder you try, the worse it gets. There is also concern that you are not able to please your partner – that feeds it. Your partner also can add to anxiety by shutting down and not wanting sex which also exacerbates the problem. I find the same as a cause of my having difficulty reaching an orgasm (Anorgaasmia)…the harder I try the more difficult it is to reach. Just when I feel it’s about to occur, I think about it, tighten up, and it’s lost. It’s difficult to get myself to relax. It’s by no means the only cause – but it certainly doesn’t help.
Just my thoughts on the subject…