# Erections **URL:** \ **Category:** Factual Questions\ **Created:** [February 26, 2009, 10:57am UTC](https://boards.straightdope.com/t/erections/487493 "2009-02-26T10:57:19Z")\ **Posts on this page:** 14\ **Page:** 1
**Author:** ![copperwindow](https://avatars.discourse-cdn.com/v4/letter/c/4af34b/32.png) [@copperwindow](https://boards.straightdope.com/u/copperwindow)\ **Post date:** [February 26, 2009, 10:57am UTC](https://boards.straightdope.com/t/erections/487493/1 "2009-02-26T10:57:19Z")
I’ve had an erection before for a good 50 mins before. With no blood circulation for so long, how does my penis not die? ---
**Author:** ![History\_Mystery\_and\_the\_Wolf](https://avatars.discourse-cdn.com/v4/letter/h/53a042/32.png) [@History\_Mystery\_and\_the\_Wolf](https://boards.straightdope.com/u/History_Mystery_and_the_Wolf)\ **Post date:** [February 26, 2009, 11:03am UTC](https://boards.straightdope.com/t/erections/487493/2 "2009-02-26T11:03:22Z")
Well it’s clear that at least one of your assumptions are incorrect. I’m going to take a punt and go with “The penis has no blood circulation while erect”. Evidence? Well apart from the obvious, ‘not turning blue and going cold’ thing, I’d like to cite _Throbbing Members_. Because I can. ---
**Author:** ![Mudshark](https://avatars.discourse-cdn.com/v4/letter/m/f04885/32.png) [@Mudshark](https://boards.straightdope.com/u/Mudshark)\ **Post date:** [February 26, 2009, 11:13am UTC](https://boards.straightdope.com/t/erections/487493/3 "2009-02-26T11:13:37Z")
When you have an erection, the blood still circulates in your penis. The erectile tissues inside the penis are filled with blood, and blood flow is increased to those. Blood becomes trapped in the tissues, but some still flows to the rest of the penis (preventing penis death). The only time I can imagine when having all that blood trapped in there could be bad, is if you left a cock ring on for too long. ---
**Author:** ![si\_blakely](https://avatars.discourse-cdn.com/v4/letter/s/d9b06d/32.png) [@si\_blakely](https://boards.straightdope.com/u/si_blakely)\ **Post date:** [February 26, 2009, 11:30am UTC](https://boards.straightdope.com/t/erections/487493/4 "2009-02-26T11:30:51Z")
[Priapism](http://en.wikipedia.org/wiki/Priapism) (an extended period of erection) does not warrant medical intervention unless it persists for over four hours, apparently. Si ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [February 26, 2009, 2:37pm UTC](https://boards.straightdope.com/t/erections/487493/5 "2009-02-26T14:37:40Z")
This is not the first time I’ve seen a question like this on the board. I think there must be some common cultural misconception somewhere that a stiffy is caused by blood draining from the penis. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [February 26, 2009, 2:40pm UTC](https://boards.straightdope.com/t/erections/487493/6 "2009-02-26T14:40:16Z")
> [@friedo](#): > > This is not the first time I’ve seen a question like this on the board. I think there must be some common cultural misconception somewhere that a stiffy is caused by blood draining from the penis. I think it’s the other way 'round. The misconception is that the blood goes in and never comes out. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [February 26, 2009, 4:40pm UTC](https://boards.straightdope.com/t/erections/487493/7 "2009-02-26T16:40:14Z")
Obviously the blood is flowing better during an erection. [This article](http://www.menshealth.com/cda/article.do?site=MensHealth&channel=health&category=sexual.health&conitem=fc623016bec6c110VgnVCM10000013281eac ____&page=0&print=true&url=http%3A%2F%2Fwww.menshealth.com%2Fcda%2Farticle.do%3Fsite%3DMensHealth%26channel%3Dhealth%26category%3Dsexual.health%26conitem%3Dfc623016bec6c110VgnVCM10000013281eac____ %26page%3D0) states that your non-sexual erections (like at night) are to keep the blood flowing to the penis: > [@](#): > > “My theory is that the flaccid penis is in a precarious state of oxygen delivery, and erections serve as a way of more or less recharging the battery,” says Irwin Goldstein, M.D., the director of sexual medicine at San Diego’s Alvarado Hospital and editor-in-chief of the Journal of Sexual Medicine. To study this possibility, Dr. Goldstein and his colleagues took samples of penile smooth muscle and subjected them to varying levels of oxygen. The results: During the low-oxygenation levels associated with flaccidity, smooth muscle begins to break down and convert to scar tissue. But at the higher oxygen levels seen during erections, the body naturally produces enzymes that undo the damage. ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [February 26, 2009, 5:05pm UTC](https://boards.straightdope.com/t/erections/487493/8 "2009-02-26T17:05:46Z")
Blood doesn’t flow willy nilly all over your body. It’s kept in a very precise path by blood vessels and capillaries. Some of the blood vessels lead to the spongy tissue on either side of your penis, and valves keep the blood there for a while (in your example, 50 minutes) while special muscles keep them closed. But in the meantime, there’s another 6 liters or so of blood that still going around your body in all the other blood vessels and capillaries (called “systemic capillaries”), feeding cells\* and taking away their waste products. Some of these go into your penis, of course, but they’re not directly connected to the spongy part that’s holding the blood giving you an erection. That erectile blood also is not nourishing or removing waste from your penis’ cells at that time; it’s only there for structural support. So, what was the question again? Oh, right. Blood flow _is_ happening into and out of your penis while you have an erection. Blood flow in the systemic capillaries, that is. The blood making you hard isn’t in the systemic capillaries, but the spongiform tissue. \*Technically, they don’t feed the cells \*directly \*- nutrients pass with water from the capillaries into the interstitial fluid and then into the cell while wastes pass out of the cell into the interstitial fluid and then the capillaries because of oncotic and hydrostatic pressure differences and ~10% of the interstitial fluid doesn’t make it back into the capillaries as plasma but becomes lymph, but I’ve probably bored you by now. Sorry. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [February 26, 2009, 5:21pm UTC](https://boards.straightdope.com/t/erections/487493/9 "2009-02-26T17:21:05Z")
> [@WhyNot](#): > > … > > So, what was the question again? Oh, right. Blood flow _is_ happening into and out of your penis while you have an erection. Blood flow in the systemic capillaries, that is. The blood making you hard isn’t in the systemic capillaries, but the spongiform tissue. > > \*Technically, they don’t feed the cells \*directly \*- nutrients pass with water from the capillaries into the interstitial fluid and then into the cell while wastes pass out of the cell into the interstitial fluid and then the capillaries because of oncotic and hydrostatic pressure differences and ~10% of the interstitial fluid doesn’t make it back into the capillaries as plasma but becomes lymph, but I’ve probably bored you by now. Sorry. Superb answer, really. And next time I’m troubled by an over-achieving erection; I shall reread driving my conscious mind and penis flaccid again. ---
**Author:** ![Thing\_Fish](https://avatars.discourse-cdn.com/v4/letter/t/ecb155/32.png) [@Thing\_Fish](https://boards.straightdope.com/u/Thing_Fish)\ **Post date:** [February 26, 2009, 7:19pm UTC](https://boards.straightdope.com/t/erections/487493/10 "2009-02-26T19:19:17Z")
> [@copperwindow](#): > > I’ve had an erection before for \*\*\*a good 50 mins \*\*\*before. With no blood circulation for so long, how does my penis not die? (emphasis mine) I’m sure it was. ---
**Author:** ![copperwindow](https://avatars.discourse-cdn.com/v4/letter/c/4af34b/32.png) [@copperwindow](https://boards.straightdope.com/u/copperwindow)\ **Post date:** [February 26, 2009, 10:16pm UTC](https://boards.straightdope.com/t/erections/487493/11 "2009-02-26T22:16:24Z")
> [@Mudshark](#): > > When you have an erection, the blood still circulates in your penis. The erectile tissues inside the penis are filled with blood, and blood flow is increased to those. Blood becomes trapped in the tissues, but some still flows to the rest of the penis (preventing penis death). The only time I can imagine when having all that blood trapped in there could be bad, is if you left a cock ring on for too long. Well, if blood is still flowing, why is priapism dangerous? ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [February 26, 2009, 10:40pm UTC](https://boards.straightdope.com/t/erections/487493/12 "2009-02-26T22:40:47Z")
It can cause damage to the blood vessels in the penis, as well as dickular[sup]1[/sup] blood clots, which are very bad. [sub]1. Medical term[/sub] ---
**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\ **Post date:** [February 27, 2009, 1:11am UTC](https://boards.straightdope.com/t/erections/487493/13 "2009-02-27T01:11:05Z")
> [@copperwindow](#): > > Well, if blood is still flowing, why is priapism dangerous? Usually it’s not dangerous itself, although there is some risk of that trapped blood in the spongiform tissue making clots. Clots are not cool because inevitably they get released, and when they make their way into the lungs, Bad Things Happen. But priapism is often a sign of other problems, and those problems - like blood pressure disorders, leukemia or spinal cord lesions (among other possibilities) might have other more dangerous effects. The priapism is sometimes the most noticeable sign, even if not the most dangerous one. ---
**Author:** ![cgg419](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cgg419/32/2847_2.png) [@cgg419](https://boards.straightdope.com/u/cgg419)\ **Post date:** [February 27, 2009, 6:56am UTC](https://boards.straightdope.com/t/erections/487493/14 "2009-02-27T06:56:15Z")
> [@friedo](#): > > It can cause damage to the blood vessels in the penis, as well as **dickular** [sup]1[/sup] blood clots, which are very bad. > [sub]1. Medical term[/sub] Bolding mine I just did a spit take 😃