# sleeping and erections. **URL:** \ **Category:** Factual Questions\ **Created:** [October 11, 2011, 5:09am UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265 "2011-10-11T05:09:54Z")\ **Posts on this page:** 10\ **Page:** 2
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [October 12, 2011, 7:04pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/21 "2011-10-12T19:04:28Z")
> [@RealityChuck](#): > > No, no, no, no, no. > > [Erections are a normal part of REM sleep](http://en.wikipedia.org/wiki/Rapid_eye_movement_sleep#Physiology) (see second paragraph), so much so that a lack of them is a way of diagnosing erectile dysfunction (look up “[postage stamp test](http://www.nlm.nih.gov/medlineplus/ency/article/003339.htm)”). > > It has nothing to do with a full bladder, and is present in any dreams, erotic or otherwise. Sounds cute. 11 years ago I had a nocturnal penile plethysmograph test for ED. You sleep for a night with a small data recorder strapped to your thigh. Attached to the data recorder are a pair of rings that fit gently around your penis. The rings mechanically constrict every few seconds, and the recorder measures your penis’s resistance to that constriction. Flaccid? The rings contract easily without much resistance. Erect? the rings encounter resistance when they contract. Unlike the one-shot postage stamp, the data recorder builds a record of erectile activity over the course of the entire night. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [October 12, 2011, 7:58pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/22 "2011-10-12T19:58:58Z")
> [@BigT](#): > > It won’t die because, as far as I know, no test has been done to prove that there is no connection. So we rely on anecdotes. But if there’s a connection, why take Viagra? Why not just drink a couple of beers? How many times a day do you have to pee? Do you have an erection every time? ---
**Author:** ![Darth\_Panda](https://avatars.discourse-cdn.com/v4/letter/d/ee7513/32.png) [@Darth\_Panda](https://boards.straightdope.com/u/Darth_Panda)\ **Post date:** [October 12, 2011, 11:01pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/23 "2011-10-12T23:01:42Z")
> [@Machine\_Elf](#): > > Sounds cute. > > 11 years ago I had a nocturnal penile plethysmograph test for ED. Was the test graded on a curve? ---
**Author:** ![Dag\_Otto](https://avatars.discourse-cdn.com/v4/letter/d/439d5e/32.png) [@Dag\_Otto](https://boards.straightdope.com/u/Dag_Otto)\ **Post date:** [October 13, 2011, 12:35am UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/24 "2011-10-13T00:35:28Z")
> [@tdn](#): > > But if there’s a connection, why take Viagra? Why not just drink a couple of beers? > > How many times a day do you have to pee? Do you have an erection every time? The local liquor store was running a promotion on a wine. I snerked when I read the name: Morningwood wine. The clerks really didn’t care to comment on this when I asked “really?”, I guess they had heard enough already. After reading this thread, I’m starting to wonder if I should try a bottle or two. ---
**Author:** ![RealityChuck](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/realitychuck/32/195_2.png) [@RealityChuck](https://boards.straightdope.com/u/RealityChuck)\ **Post date:** [October 13, 2011, 1:08am UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/25 "2011-10-13T01:08:12Z")
> [@BigT](#): > > It won’t die because, as far as I know, no test has been done to prove that there is no connection. So we rely on anecdotes. There have been numerous tests conducted on sleeping subjects. Erections during REM sleep are well-documented. Similar arousal is found in women during REM sleep. Both are measured by sensors while an EEG is being taking. REM sleep gives a recognizable patter on EEGs and other sensors confirm that an erection is present. > [@](#): > > slightly TMI: > > I know that, every time I’ve had a post awakening erection, I’ve needed to pee around 16 oz or so, but I when I don’t need to pee much, my penis is always flaccid. I also know that I’ve woken many times during REM sleep without an erection, and I am very clearly not impotent. It’s mind-boggling ironic that you’re complaining about scientists relying on anecdotes only to support your side simply by supplying an anecdote. The difference is that the effect _has_ been studied and is so dependable that a lack of it is a sign of erectile problems. Do you really think doctors use this as a tool if there hasn’t been studies that proved it so? As **Machine Elf** confirms, doctors use this fact as a diagnostic tool. They’ve just moved on from postage stamps. And **tdn** raises and important question that you need to answer: if it’s caused by needing to pee, why don’t you get erections during the day when you have a full bladder? ---
**Author:** ![elfkin477](https://avatars.discourse-cdn.com/v4/letter/e/a9a28c/32.png) [@elfkin477](https://boards.straightdope.com/u/elfkin477)\ **Post date:** [October 13, 2011, 5:06am UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/26 "2011-10-13T05:06:07Z")
**Machine Elf** , no probe up your behind, though? I have a book on sleep and it describes the methodology for the R.E.M. study that wiki article alluded to - for both men and women they _also_ had anal probes, not just a ring around the penis/some sort of probe to monitor the clitoris. All I can say is that the folks they studied must be champion sleepers because I can’t imagine sleeping with probes in both orifices! ---
**Author:** ![Rigamarole](https://avatars.discourse-cdn.com/v4/letter/r/77aa72/32.png) [@Rigamarole](https://boards.straightdope.com/u/Rigamarole)\ **Post date:** [October 13, 2011, 5:52am UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/27 "2011-10-13T05:52:21Z")
> [@elfkin477](#): > > All I can say is that the folks they studied must be champion sleepers because I can’t imagine sleeping with probes in both orifices! Ahem. Some of us can. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [October 14, 2011, 5:50pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/28 "2011-10-14T17:50:10Z")
As I recall, Dr. Oz or some other physician discussed this on The View, which piqued the interest of the cohosts and largely female audience. He said it is a simple natural part of the male process - all night long Mister Ed goes up and down, up and down. It’s sort of like nature is verifying all systems are go. If you wake up at “full mast” time, morning wood. He also mentioned it is an indicator of true medically-caused ED problems when this does not happen. Back before pyjamas, I assume there would have been an evolutionary advantage to this function. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 14, 2011, 6:37pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/29 "2011-10-14T18:37:29Z")
The penis needs blood flow, just like any other organ. This is true regardless of whether you wear pajamas. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [October 14, 2011, 9:42pm UTC](https://boards.straightdope.com/t/sleeping-and-erections/599265/30 "2011-10-14T21:42:33Z")
It has regular blood flow; except when inflated, the flow is somewhat limited. (Hence the “if you have an erection that lasts more than 4 hours…” warning). They say humour is lost on some people. Back in the cavemen days, there was a reproductive advantage to frequently being locked and loaded while sleeping in a huddled mass group. [Previous page](https://boards.straightdope.com/t/sleeping-and-erections/599265.md?page=1)