Talk:Stroke volume

Relationship between heart rate, stroke volume and strain on heart

I'm not sure that slower rate -> larger stroke volume -> decreased strain on heart. I'm not a doctor, but AFAIK, slower rate is a result of a stronger muscle with somewhat larger chambers that beats slower when at rest, and is capable of much higher performance than the untrained heart. Strain is further reduced by a decrease in the viscosity of blood. Anyone, anyone?... Wake 04:54, 14 Dec 2003 (UTC)

I realize this question is more than two years old, but I thought I'd quickly address a simple point here. A slower heart rate allows more time for diastole (ventricular relaxation), giving the ventricles more time to fill with blood, thereby increasing stroke volume. This allows cardiac output to remain high without straining the heart (eg, by making it beat more rapidly). I'm not aware of any changes that exercise has on blood viscosity, though. Cheers, David Iberri (talk) 00:44, 18 February 2006 (UTC)

I don't know where to write this, but in response to the above, we were told by a Hubs (Human Body Systems) Lecturer that the time spent in diastole doesn't really affect the amount flowed into the heart, as this speeds up to compensate when heart rate increases, vica versa. Summary: SV independant of time in diastole --Africantearoa (talk) 09:52, 9 September 2008 (UTC)

Well as you said endurance trained athletes have higher max stroke volume et lower max heart rate which allows higher max cardiac output at severe exercise. Thus their blood velocity is heigher, which may cause oxygen diffusion impairement in human lungs. Blood transit time through capillaries in the lungs is reduced which does not allow oxygen to diffuse totally from the alveoli to the capillary. This phenomenon is called Exercise Induced Hypoxemia and may result in a slight decrease in arterial oxygen saturation. This desaturation may be dramatically increased if your are exercising at altitude, where inspired oxygen pressure (PiO2) is reduced. The_FD Paris 08 March 2007

Oh yes, and as for blood viscosity, endurance training is known to increase plasma volume and thus decrease blood viscosity. This improves blood outflow in the smallest muscle blood capillaries and may reduce oxygen diffusion distance. However if training takes place at altitude blood viscosity may be increased since it brings erythrocytes production up.

what happens to haemoglobin after several weeks of excersice?

Re:What happens to haemoglobin after several weeks of exercise? --210.54.53.12 01:06, 27 Jun 2005 (UTC)

As far as I know there are three different effects

- The most well known and the one endurance athletes are looking for is an up regulation of EPO hormone inducing a higher production of haemoglobin (which means your blood can carry more oxygen to your muscles). Though that does not mean your hematocrit will be higher because endurance training also involves a higher plasma volume and hematocrit is defined as the percentage "haemoglobin/plasma volume"

- The second effect is as follows: during exercise you maintain a high cardiac output which means a higher blood pressure in vessels and a higher speed of circulation. This breaks some haemoglobin molecules. However this is not significant compared to the increase of red cells number obtained thanks to several weeks of training.

- The third effect is a short time effect which is a higher blood haemoglobin concentration at the end of a given exercise compared to the beginning. This is because of a decrease of plasma volume due to sudation.

Stroke volume describes half the work of the myocardium and is readily extrapolated to ejection fraction (EF), end systolic volume (ESV) and minimum Volume (minV). Seen as multiple variables seeking the same answer, they all readily elaborate systole. Systole is the sum of many parts, first and foremost being electrical and mechanical components. The inverse half of myocardial work happens in diastole. Diastole readily implies ESV plus EDV or injection fraction (blood pumped into each heart chamber in one cycle), end diastolic volume (EDV)and maximum Volume (maxV). Inexpensive. noninvasive echocardiography readily renders these variables today. One might argue a compendium is required to keep track of the determinants of myocardial work as they are technologically revealed. —Preceding unsigned comment added by 24.211.109.44 (talk) 00:20, 15 October 2007 (UTC)

Right ventricle or no?

The article reads: "Stroke volume (SV) is the volume of blood pumped by the right/left ventricle of the heart in one contraction.

The stroke volume is not all of the blood contained in the left ventricle. The heart does not pump all the blood out of the ventricle.". So does it include the right ventricle output or not? I believe not, but this is unclear. Thanks --Irrevenant [ talk ] 04:39, 12 April 2008 (UTC)

Stroke volumes and approximately 70 mL in a healthy 70-kg man

I did a rvt on an edit by CrafterNova,[1] where they changed "The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70-kg man." to "The stroke volumes for each ventricle are generally equal, both being approximately 70 mL in a healthy 70-kg person." They cited WP:NPOV and MOS:NB. But for sex differences, we are supposed to have accurate reporting on this.

CrafterNova, with resources, will you explain why you made the edit? You want us to say that "70 mL in a healthy 70-kg" applies to anyone else? Including children? I usually find that anatomy and biology books give these numbers for adult males. But I went ahead and looked at some resources to assess varied descriptions. On page 144 for "Exercise Physiology: Integrating Theory and Application", it says, "Typical values for heart rate and stroke volumes at rest for a normal-sized untrained male (70 kg) and female (50 kg) are approximately 72 beats min and 70 mL, and 75 beats min and 60 mL, respectively."[2] On pages 133-134 of "Introduction to Anatomy and Physiology for Healthcare Students", it says, "For example, the stroke volume (SV) for an average 70 kg man is about 70 ml and the (left ventricular) end-diastolic volume (EDV) is about 120 ml."[3]

Maybe you mean what "Cardiovascular Physiology: A Clinical Approach" says? On page 94, it says, "Stroke volume at rest is 70 mL/beat in the average size person and the resting HR is around 70 beats/min; using the equation above, we get a CO of 4,900 mL/min (or close to 5 L/min)."[4]. GBFEE (talk) 22:06, 30 June 2022 (UTC)

• @GBFEE: Right now, as I'm quite busy, I don't have sources for the changes I want to be made, but I will surely try to provide reliable sources for these changes.

"Typical values for heart rate and stroke volumes at rest for a normal-sized untrained male (70 kg) and female (50 kg) are approximately 72 beats min and 70 mL, and 75 beats min and 60 mL, respectively."

"Stroke volume at rest is 70 mL/beat in the average size person and the resting HR is around 70 beats/min; using the equation above, we get a CO of 4,900 mL/min (or close to 5 L/min)."

These sentences should be mentioned in the article.

"I usually find that anatomy and biology books give these numbers for adult males"

Firstly, there are more than 2 genders (and there are 3 sexes; male, female and intersex), that is, gender and sex are not binary but are wide-ranging biological spectrums.

Secondly, this article (and many other articles) don't mention these numbers for adult females. And if there really are a lot of sex differences then why don't these sources include intersex people, non-binary people and other gender-diverse people?

Thirdly, to shatter unethical popular misconceptions, gender variance is not limited to only humans; it has also been found in animals. That's right. Animals can also be transgender and/or non-binary. Gender diversity from LGBTQ+ communities is historical but also evolutionary, since genders began appearing in microorganisms called protists. This should clear up some things about the differences between gender and sex.

That being said, this article is missing a lot of scientific literature about sex differences. LGBTQ content does not have to be included in this article, but it should conform to gender neutrality as WP:NPOV and MOS:NB. —CrafterNova ^{[ TALK ]  [ CONT ]} 17:59, 1 July 2022 (UTC)

• CrafterNova, MOS:NB has no relevance at this article. Our sex differences articles, such as sex differences in human physiology, are about sex differences in males and females. If you have resources that support the idea that people of third gender and non-binary gender identities have different anatomy/physiology than those that fall under the male and female categories, you should provide them in this discussion. And if you want our sex differences articles to include multiple genders, one place you can propose this is at WT:ANAT. I'll leave a message there about this discussion for more comments. But you will definitely need to provide resources that people of third gender and non-binary gender identities have different anatomy/physiology than those that fall under the male and female categories and that mentioning people of these varied gender identities is due in sex differences articles or physiology ones such as this one. You said it yourself: there are differences between sex and gender. You've also made unsupported and unscientific claims in this discussion, but I won't address those. GBFEE (talk) 20:44, 1 July 2022 (UTC)

• @GBFEE:

"MOS:NB has no relevance at this article."

Like I said, LGBTQ content does not need to be necessarily included in this article. It just has to be gender neutral, a neutrality criteria that is mentioned at WP:NPOV. As far as I have searched Wikipedia's policies, MOS:NB is the most relevant policy I could find for LGBTQ content.

"Our sex differences articles, such as sex differences in human physiology, are about sex differences in males and females."

That is unethical to say so. Intersex people and non-binary people are also humans, and sex differences in occur in all 3 sexes.

"You've also made unsupported and unscientific claims in this discussion, but I won't address those."

What "unscientific claims" did I make? I have provided sources for all claims I made.

"If you have resources that support the idea that people of third gender and non-binary gender identities have different anatomy/physiology than those that fall under the male and female categories, you should provide them in this discussion."

Accurate reliable sources are hard to find, and cannot be found by one or few editors alone. The sources I have mentioned prove that LGBTQ people are real, so that must become an initiative for teamwork.

"if you want our sex differences articles to include multiple genders, one place you can propose this is at WT:ANAT."

I will try proposing this initiative.

Also, the problem is not just about Wikipedia. The problem is many centuries old societal oppression against intersex people, non-binary people and other gender diverse people.
They are not "seen as normative" even when they are actually normal. This article fails to explain that fact to readers. Articles should not mislead readers. Readers and editors who are intersex have the right to objection here. Looking forward for consensus —CrafterNova ^{[ TALK ]  [ CONT ]} 03:21, 2 July 2022 (UTC)

• The fact that you are bringing up stuff like "LGBTQ people are real" (which literally no one here disputes and is completely off-topic), gender diversity in animals (again, off-topic), and this stuff about "normal" tells me you need to read WP:NOTADVOCACY. We do not alter text away from the due weight of reliable sources to WP:Right great wrongs.

No, there are not 3 sexes, there are 2. Sex is distinct from gender. Intersex conditions are also known as disorders of sex development; they are not distinct sexes. I can say this with directness because peer-reviewed biological and medical sources all agree that there are two sexes. All the sources on "sex differences" are about differences between males and females.

Of the two sources you cited claiming otherwise, one is a blog post, and the other is a non-peer-reviewed article. The way that one frames intersex conditions is not in accord with the peer-reviewed biology literature, and its author clarified that she did not mean to imply there are more than two sexes. This 2021 Endocrine Society review article, which discusses transgender matters and intersex conditions, still notes that The terms sex and gender should not be used interchangeably. Sex is dichotomous, with sex determination in the fertilized zygote stemming from unequal expression of sex chromosomal genes. By contrast, gender includes perception of the individual as male, female, or other, both by the individual and by society; both humans and animals have sex, but only humans have gender. Both sexes produce estrogens, androgens, and progestins;...Sex is a biological concept. Asexual reproduction (cloning) is routine in microorganisms and some plants, but most vertebrates and all mammals have 2 distinct sexes. Etc. (Emphasis added.) All the biological peer-reviewed literature agrees on this point. Variation in certain traits, such as from developmental conditions, is a distinct matter from how many sexes there are.

We are not going to make content on sex differences gender neutral, as that is against how the sources treat the topic, and would be obfuscation in service of a personal agenda. Based on your comments here and at Talk:Endosex, you need to put sociopolitical goals aside and focus on following the reliable medical sources. You also should not be accusing editors of being "unethical" for stating facts about the reliable sources. Crossroads ^-talk- 00:24, 3 July 2022 (UTC)

• Yes, I'm going to agree with what has already been said here: this must clearly follow sourcing, for several policy and practical reasons relating to effective and transparent (that is to say, consistent with the wording of the sourcing) prose on a MEDRS topic. But perhaps the most notably these considerations is the very policy Crafter has cited: WP:NPOV. The other policy they reference: WP:NB is clearly not even remotely relevant here: that piece of policy provides guidance on how to reference the socially presented gender chosen and expressed by particular subjects of biographical articles. It has absolutely nothing to do with this novel proposal that any time any article references sex, it must be within the a semantic construction that expressly notes the existence of intersex persons. I'm sorry, I'm as pro recognition as the next person, but that's clearly an unworkable, frankly silly suggestion. Now, as to...

"Also, the problem is not just about Wikipedia. The problem is many centuries old societal oppression against intersex people, non-binary people and other gender diverse people."

You really will want to read WP:RGW. We are not here to raise a banner to the topic of gender assignment politics or intersex erasure at every opportunity in every article. This is an article about a clinical, empirical topic in the field of cardiac physiology: clearly we are going to use language which shoes fidelity to the sources and respect and consideration for our reader's needs. The suggestion that we eliminate or alter the identifying terminology employed in sources to pay lip service to the topic social gender normatization is not just ill-considered, it is actually the proposition that in truth threatens to erase the truth of intersex persons. Because intersex persons, being in part the product of the functioning of their gonads and of their epigenetics (just as with all persons), may not in fact in general have exactly the same stroke volume as those identified by the research in question as "male". So clouding that fact or generating inaccurate or speculative factual implications not found in the sources, out of a ham-fisted rush to appear inclusive would not just be a bad idea: it would be arguably quite unethical.

"They are not "seen as normative" even when they are actually normal. This article fails to explain that fact to readers."

Why would this article be expected to explain that fact? I don't see any way in which the wording being discussed implies that intersex person are not "normal". They just don't happen to easily fall into one of the broad categories of people that happened to be referenced in the sources being used for this article...and that's ok. They are empiricists using reasonable data categories to improve the general understanding of human health.

"Accurate reliable sources are hard to find, and cannot be found by one or few editors alone."

Yeah...that's not how this project works. If you want to make a principled argument for rejection (or alteration/nuancing) of sourced content, the WP:ONUS is upon you to provide the WP:reliable sourcing for WP:verification.

"The sources I have mentioned prove that LGBTQ people are real

I don't see where anyone you have been speaking with here has said anything that even remotely questions that assertion... Also, not all intersex persons consider themselves LGBTQ, so I'm not sure why you are using the terms interchangeably here.

In short, I think this one has got to be realistically classed as a WP:SNOW call. SnowRise ^{let's rap} 07:59, 23 July 2022 (UTC)

Also, CrafterNova, could you please follow WP:THREAD and a more typical response structure for responding to other editors, rather than outdenting to the first level for every single response. It kind of makes an undreadable mess out of the discussion. Thank you in advance. SnowRise ^{let's rap} 08:04, 23 July 2022 (UTC)

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