Can High Hematocrit Cause Hypertension?

[MikeDaly1970]

Hi guys,

I know that I have high hematocrit, and I'm booked in for donation next Tuesday.

My question is, can high hematocrit cause hypertension, as my doc says I've now high blood pressure, he says my high hematocrit does not cause high blood pressure, but my research says different.

What do you guys think?

Thanks

 

[Deleted member 16042]

My personal experience, yes at 52-54% my systolic BP increases

 

[MikeDaly1970]

Thank you very much Blackhawk

Has anyone any good links to this so I can show my doctor, he denies Haemotcrit can raise diastolic blood pressure

 

[Nelson Vergel]

Yes, high hematocrit can cause hypertension. Hematocrit refers to the proportion of blood volume that is occupied by red blood cells. An elevated hematocrit level increases blood viscosity, which in turn can elevate blood pressure through several mechanisms.

Mechanisms Linking High Hematocrit to Hypertension

1. **Increased Blood Viscosity**:
- High hematocrit levels increase the viscosity of blood, which raises the resistance to blood flow. This increased resistance can lead to higher blood pressure as the heart must work harder to pump the thicker blood through the circulatory system[1][2][4][5][9].

2. **Peripheral Vascular Resistance**:
- Elevated hematocrit levels are associated with increased peripheral vascular resistance. This is partly due to the increased viscosity but also due to the reduced ability of blood vessels to dilate properly, which further contributes to higher blood pressure[1][3][5].

3. **Endothelial Function**:
- High hematocrit levels can impair endothelial function, reducing the production of nitric oxide, a vasodilator. This impairment can lead to vasoconstriction and increased blood pressure[10][13][15].

Evidence from Studies

- **General Population Studies**:
- Studies have shown a significant association between high hematocrit levels and the prevalence of hypertension. For instance, a study reported that a 10-unit increase in hematocrit (e.g., from 35% to 45%) is associated with an increase of 4-6 mm Hg in arterial pressure and a twofold increased risk of hypertension[1].

- **Polycythemia and Hypertension**:
- Polycythemia, a condition characterized by an increased number of red blood cells, is strongly associated with hypertension. Patients with polycythemia have a higher prevalence of hypertension compared to controls, even after adjusting for other risk factors[2][6][7][8][12][14].

- **Longitudinal Studies**:
- Longitudinal studies have demonstrated that men with higher hematocrit levels have an increased risk of developing hypertension over time. For example, a study found that men whose hematocrit increased over time had a 25% increased risk of developing hypertension compared to those whose hematocrit decreased[4][19].

Clinical Implications

- **Management of Hematocrit Levels**:
- Managing hematocrit levels can be crucial in controlling blood pressure, especially in conditions like polycythemia vera. Treatments such as phlebotomy, which reduces hematocrit levels, can help manage hypertension in these patients[12][14].

- **Risk Prediction**:
- Hematocrit levels can serve as a prognostic marker for hypertension, aiding in the early detection and management of high blood pressure in at-risk individuals[5].

In summary, high hematocrit levels are causally associated with hypertension through mechanisms involving increased blood viscosity, peripheral vascular resistance, and impaired endothelial function. This relationship is supported by various studies across different populations and conditions.

Citations:
[1] https://www.ahajournals.org/doi/pdf/10.1161/01.HYP.20.3.319
[2] Gaisböck syndrome (polycythemia and hypertension) revisited: results from the national inpatient sample database - PubMed
[3] Blood Pressure and Hematocrit in Diabetes and the Role of Endothelial Responses in the Variability of Blood Viscosity
[4] High blood hematocrit increases the risk of the incidence of hypertension in men
[5] Association of hematocrit with blood pressure and hypertension
[6] Gaisböck syndrome (polycythemia and hypertension)... : Journal of Hypertension
[7] Blood pressure profile, sympathetic nervous system activity, and subclinical target organ damage in patients with polycythemia vera - Polish Archives of Internal Medicine
[8] Polycythemia vera as a rare cause of hypertension in a young man
[9] Effect of hematocrit on blood pressure via hyperviscosity
[10] Managing High Blood Pressure: The Cardiologist’s Perspective | ASH Clinical News | American Society of Hematology
[11] Polycythaemia and hypertension caused by renal artery stenosis | Archives of Disease in Childhood
[12] Polycythemia Vera: What It Is, Symptoms & Treatment
[13] Hemoglobin and hematocrit levels are positively associated with blood pressure in children and adolescents 10 to 18 years old - Scientific Reports
[14] https://www.hopkinsmedicine.org/health/conditions-and-diseases/polycythemia-vera
[15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2214674/
[16] https://www.cedars-sinai.org/health-library/diseases-and-conditions/p/polycythemia-vera.html
[17] https://journals.physiology.org/doi/10.1152/ajpheart.00496.2010
[18] https://www.ajconline.org/article/0002-9149(66)90430-9/abstract
[19] https://journals.lww.com/jhypertens...od_hematocrit_predicts_hypertension_in.9.aspx

 

[MikeDaly1970]

Wow thank you very much Nelson

Can I ask.a final question to ease my mind.

next week I'm having blood donation will.this bring my blood pressure back to so called normal, it's only gotten higher since haemotcrit got higher

 

[Nelson Vergel]

next week I'm having blood donation will.this bring my blood pressure back to so called normal, it's only gotten higher since haemotcrit got higher

How much is your hematocrit now and your blood pressure?

 

[MikeDaly1970]

Haemotcrit 52.1

Blood pressure 140/97

 

[MikeDaly1970]

Haemotcrit 52.1

Blood pressure 140/97

Have bad bad headaches, facial flushing,

 

[Nelson Vergel]

I hope you did not donate less than 3 months ago.

Yes, donating plus good hydration should reduce your hematocrit by 3 points and most probably reduce your BP if your body weight, caffeine consumption, and sleep have been stable.

 

[MikeDaly1970]

Never donated b4, and I'm on testosterone 7 years only now is haemotcrit high

Thank you Nelson

 

[MikeDaly1970]

Lastly, is one pint considered the donation for haemotcrit to drop by 3 points, thanks again appreciate all this feel relieved now

 

[Nelson Vergel]

Yes. If this is the first time your hematocrit has been high in 7 years, why do you think it happened ? Did you change dose or not hydrate well ?

 

[MikeDaly1970]

Probably not hydrating well tbh, will do so moving forward

 

[Nelson Vergel]

Get a new test. Although one donation won’t kill you or decrease your iron much.

 

[Systemlord]

If this is the first time your hematocrit has been high in 7 years, why do you think it happened ?

Sleep apnea can cause an increase in hematocrit. You may not even be aware that you even have it unless your partner can confirm.

 

[Seagal]

Haemotcrit 52.1

Blood pressure 140/97

Seems there is a correlation and explanations for a causation but my values are:
Hematocrit 53
Blood pressure 120/80


And measure your blood pressure at home. Most bp measurements at the physician are higher because the mental stress/tension you might experience in this circumstance can increase blood pressure.
Anyway, around 140/100 is not just slightly elevated. What was the pulse frequency? ...your doc will figure this out. Relax!

 

[buckeye22]

Yes it can raise your BP. You can donate 1 unit of blood every 62 days. Although I wouldn’t recommend that often. I donate every 90 days for high hemoglobin and hematocrit. I’m usually around 18 hemoglobin which is approximately 56 hematocrit. It generally drops about 2 - 3 points. You can also give whole blood which is 2 units but then it’s every 120 days. I stick to only 1 unit every 90 days and that’s worked out great. Plus you are helping someone in need. Download the red cross app and book an appointment and track your blood donations.

 

[Seagal]

Seems there is a correlation and explanations for a causation but my values are:
Hematocrit 53
Blood pressure 120/80


And measure your blood pressure at home. Most bp measurements at the physician are higher because the mental stress/tension you might experience in this circumstance can increase blood pressure.
Anyway, around 140/100 is not just slightly elevated. What was the pulse frequency? ...your doc will figure this out. Relax!

I need to add to my post that at my lab report the reference range of hematocrit is 40-53%.
Obviously there must be an additional variable which regulates blood pressure. Thus the presence of high hematocrit can result in high blood pressure if this other variable is off, or cannot properly adjust to this state. And the risk of this happening is probably larger with trt induced elevation of hematocrit from one's baseline.

 

[Deleted member 16042]

Yes it can raise your BP. You can donate 1 unit of blood every 62 days. Although I wouldn’t recommend that often. I donate every 90 days for high hemoglobin and hematocrit. I’m usually around 18 hemoglobin which is approximately 56 hematocrit. It generally drops about 2 - 3 points. You can also give whole blood which is 2 units but then it’s every 120 days. I stick to only 1 unit every 90 days and that’s worked out great. Plus you are helping someone in need. Download the red cross app and book an appointment and track your blood donations.

I am assuming you are referring to some kind of blood donation center criteria, Red Cross is every 56 days, but that is not the whole story. Too many men have posted here about their ferritin being depleted from too many blood donations, even at that approved frequency.

If you are donating, monitor your ferritin.

 

[RobRoy]

Yes, high hematocrit can cause hypertension. Hematocrit refers to the proportion of blood volume that is occupied by red blood cells. An elevated hematocrit level increases blood viscosity, which in turn can elevate blood pressure through several mechanisms.

Mechanisms Linking High Hematocrit to Hypertension

1. **Increased Blood Viscosity**:
- High hematocrit levels increase the viscosity of blood, which raises the resistance to blood flow. This increased resistance can lead to higher blood pressure as the heart must work harder to pump the thicker blood through the circulatory system[1][2][4][5][9].

2. **Peripheral Vascular Resistance**:
- Elevated hematocrit levels are associated with increased peripheral vascular resistance. This is partly due to the increased viscosity but also due to the reduced ability of blood vessels to dilate properly, which further contributes to higher blood pressure[1][3][5].

3. **Endothelial Function**:
- High hematocrit levels can impair endothelial function, reducing the production of nitric oxide, a vasodilator. This impairment can lead to vasoconstriction and increased blood pressure[10][13][15].

Evidence from Studies

- **General Population Studies**:
- Studies have shown a significant association between high hematocrit levels and the prevalence of hypertension. For instance, a study reported that a 10-unit increase in hematocrit (e.g., from 35% to 45%) is associated with an increase of 4-6 mm Hg in arterial pressure and a twofold increased risk of hypertension[1].

- **Polycythemia and Hypertension**:
- Polycythemia, a condition characterized by an increased number of red blood cells, is strongly associated with hypertension. Patients with polycythemia have a higher prevalence of hypertension compared to controls, even after adjusting for other risk factors[2][6][7][8][12][14].

- **Longitudinal Studies**:
- Longitudinal studies have demonstrated that men with higher hematocrit levels have an increased risk of developing hypertension over time. For example, a study found that men whose hematocrit increased over time had a 25% increased risk of developing hypertension compared to those whose hematocrit decreased[4][19].

Clinical Implications

- **Management of Hematocrit Levels**:
- Managing hematocrit levels can be crucial in controlling blood pressure, especially in conditions like polycythemia vera. Treatments such as phlebotomy, which reduces hematocrit levels, can help manage hypertension in these patients[12][14].

- **Risk Prediction**:
- Hematocrit levels can serve as a prognostic marker for hypertension, aiding in the early detection and management of high blood pressure in at-risk individuals[5].

In summary, high hematocrit levels are causally associated with hypertension through mechanisms involving increased blood viscosity, peripheral vascular resistance, and impaired endothelial function. This relationship is supported by various studies across different populations and conditions.

Citations:
[1] https://www.ahajournals.org/doi/pdf/10.1161/01.HYP.20.3.319
[2] Gaisböck syndrome (polycythemia and hypertension) revisited: results from the national inpatient sample database - PubMed
[3] Blood Pressure and Hematocrit in Diabetes and the Role of Endothelial Responses in the Variability of Blood Viscosity
[4] High blood hematocrit increases the risk of the incidence of hypertension in men
[5] Association of hematocrit with blood pressure and hypertension
[6] Gaisböck syndrome (polycythemia and hypertension)... : Journal of Hypertension
[7] Blood pressure profile, sympathetic nervous system activity, and subclinical target organ damage in patients with polycythemia vera - Polish Archives of Internal Medicine
[8] Polycythemia vera as a rare cause of hypertension in a young man
[9] Effect of hematocrit on blood pressure via hyperviscosity
[10] Managing High Blood Pressure: The Cardiologist’s Perspective | ASH Clinical News | American Society of Hematology
[11] Polycythaemia and hypertension caused by renal artery stenosis | Archives of Disease in Childhood
[12] Polycythemia Vera: What It Is, Symptoms & Treatment
[13] Hemoglobin and hematocrit levels are positively associated with blood pressure in children and adolescents 10 to 18 years old - Scientific Reports
[14] Polycythemia Vera
[15] Lowering of Blood Pressure by Increasing Hematocrit with Non–Nitric Oxide–Scavenging Red Blood Cells
[16] https://www.cedars-sinai.org/health-library/diseases-and-conditions/p/polycythemia-vera.html
[17] https://journals.physiology.org/doi/10.1152/ajpheart.00496.2010
[18] https://www.ajconline.org/article/0002-9149(66)90430-9/abstract
[19] Higher blood hematocrit predicts hypertension in men : Journal of Hypertension

None of these can be extrapolated to the increase in hematocrit in men on testosterone are those that live at high altitude etc... Just looking at hematocrit is taking a very myopic view of viscosity in men on testosterone. A high baseline hematocrit is not the same as raising hematocrit with testosterone or moving to high altitude for instance. I will be giving a detailed discussion on this topic but let me just say that hematocrit is not the only determinant of blood viscosity. There is a reason why testosterone has been used and abused by tens of millions of men over the last several decades there has not been an increase in incidence of heart attacks or strokes or DVTs. There's a reason why no randomized controlled trial or prospective study has evershoen that the increase in hematocrit with testosterone has ever caused harm. People just tend to focus on hematocrit and what occurs with baseline observations.