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Orthostatic Intolerance (OI) Info Guide


Could your symptoms be caused by a treatable condition called Orthostatic Intolerance (OI)? I found out many of mine were. I found out OI was a part of another chronic illness that I had. I found out I probably had OI when I was well. I found out I was treating Orthostatic Intolerance symptoms by lying down until I felt "almost well." I found out that when I treated the OI first, I could get up and feel better and even get some exercise. I found out that most people probably do not know they have OI by itself or OI as part of another chronic illness. Since OI is a problem that can be helped, many people can feel a lot better.

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Definition of Orthostatic Intolerance (OI)

Orthostatic Intolerance (OI) is a condition where blood pools in the feet and legs when sitting or standing rather than returning to the heart and brain.

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Test for Orthostatic Intolerance (OI)

There is a simple blood pressure and pulse test for Orthostatic Intolerance (OI) that can be performed by a doctor to determine if someone has OI.

It is important to remember that most healthy people do not have Orthostatic Intolerance symptoms when they change position. (1)

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Results of Orthostatic Intolerance Test

The results of the Orthostatic Intolerance Test will show either normal blood pressure and pulse or one or more of these 5 forms of OI.

Orthostatic systolic hypotension (2) = big drop in top number
Orthostatic diastolic hypotension (2) = big drop in bottom number
Orthostatic diastolic hypertension (2) = big rise in bottom number
Orthostatic narrowing of pulse pressure (2) = small difference between both numbers
Orthostatic postural tachycardia (2) (POTS) = high pulse

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Illnesses Affected by Orthostatic Intolerance (OI)

Orthostatic Intolerance (OI) can be a single illness or problem or it can be a part of many illnesses.

Orthostatic Intolerance (OI) "is considered a failure of the autonomic nervous system -- the part of the nervous system that controls involuntary vital actions, such as the heartbeat -- to react appropriately to sudden changes. When you stand up, some blood pools in your lower extremities. Uncorrected, this would cause your blood pressure to fall. However, normally your body compensates by sending messages to your heart to beat faster and to your blood vessels to constrict. This offsets the drop in blood pressure. If this does not happen, or happens too slowly, postural hypotension results." (3, 4)

  • Dysautonomia includes forms of Orthostatic Intolerance (OI) which include (5), orthostasis (6),
    orthostatic disorder affects about 500,000 people (7)
    • Orthostatic systolic hypotension (2),
      systolic hypotension (8), neurally mediated hypotension (NMH) (5), neurally mediated orthostatic hypotension (4), delayed orthostatic hypotension (5), delayed orthostatic intolerance (9), orthostatic hypotension (4, 10), postural hypotension (4, 10), vasovagal syncope (11)
    • Orthostatic diastolic hypotension (2),
      diastolic hypotension (8)
    • Orthostatic diastolic hypertension (2),
      diastolic hypertension (8), orthostatic hypertension (12)
    • Orthostatic narrowing of pulse pressure (2),
      excessive narrowing of the pulse pressure (8)
    • Orthostatic postural tachycardia (2),
      tachycardia after standing for at least 3 minutes (8), postural orthostatic tachycardia syndrome (POTS) (5), orthostatic tachycardia (13), chronic orthostatic intolerance (COI) (14)
  • Chronic Fatigue Syndrome (CFS) (15, 16), most (up to 97 percent) of estimated 800,000 in US (17) have OI (2, 14), estimated 10 million with CFIDS/FM worldwide (18)
    Chronic Fatigue and Immune Dysfunction Syndrome (CFIDS), also known as Myalgic Encephalopathy (ME), Myalgic Encephalomyelitis (ME)
  • Shy-Drager Syndrome (SDS) (19),
    Multiple System Atrophy (MSA) (20, 21), Progressive Autonomic Failure (PAF) (20), Progressive Autonomic Failure with Multiple System Atrophy (PAF with MSA) (21), progressive autonomic disorders (20), central nervous system disorders, such as Shy-Drager syndrome, multiple system neuropathy (4), nervous system problems (1)
  • Ehlers-Danlos Syndrome (EDS) (45, 46) and other connective tissue disorders
  • Diabetes (1, 4), 10 percent of diabetics (6),
    insulin dependent diabetes mellitus (IDDM) (6), peripheral neuropathy and autonomic neuropathy (nerve problems), such as may be caused by diabetes mellitus (4), diabetic autonomic neuropathy (20), diabetic neuropathy (22)
  • affects people who live in a wheelchair,
    tetraplegia, paraplegia (23), spinal cord injuries (4)
  • Fibromyalgia (FM) (24)
  • 10 percent to 20 percent of elderly people (3, 4), common in old age (20),
    aging (4), Age-associated decline in blood pressure regulation, which may be worsened by certain health conditions or medications. (4) may increase the risk of falls, leading to the potential for bone fractures and other injuries (3), Postprandial (after meals) hypotension is estimated to affect up to one-third of elderly people and is a common cause of dizziness and falls after eating. (4)
  • Parkinson's disease (25) and Parkinson's disease medications (4, 25)
  • Addison's disease (26)
  • Mitral Valve Prolapse syndrome (MVP) (27)
  • Pheochromocytoma (13)
  • cardiovascular disorders (4)
  • Post-Polio Syndrome 91 percent (28), 20 million worldwide (18)
  • possibly Gulf War Syndrome,
    Gulf War Illness
  • Also occurs with: nutritional diseases (4), alcoholism (4), amyloidosis (caused by deposits of a waxy substance called amyloid in the body) (4), vitamin deficiencies (4), neuropathies associated with cancer, particularly lung cancer or pancreatic cancer (4)

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Other Causes of Orthostatic Intolerance (OI)

  • Orthostatic Intolerance (OI) is a side effect of certain medications (1, 4)
    • Drugs used to treat hypertension/high blood pressure (4)
      • diuretics (4)
      • beta-blockers (4)
      • calcium channel blockers (4)
      • angiotensin-converting enzyme (ACE) inhibiting drugs (4)
    • Drugs that have hypotension/low blood pressure as a side effect (4)
      • nitrates (4)
      • drugs used against Parkinson's disease (4)
      • antipsychotics (4)
      • neuroleptics (4)
      • anti-anxiety agents (4)
      • sedative-hypnotics (4)
      • tricyclic antidepressants (4)
  • dehydration (1, 4)
  • lack of food (4)
  • prolonged standing in the heat (4)
  • being generally run down (4)
  • influenced by genetic make-up (4)
  • diet (4)
  • acute triggers, such as infection and allergy (4)
  • pregnancy (4)
  • strong emotion (4)
  • hardening of the arteries (4)
  • electrolyte loss, which may result from another condition, such as diarrhea or vomiting (4) or excessive blood loss during female menstruation (4)

Two-thirds of astronauts also experience OI. (7, 29, 30)

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Symptoms of Orthostatic Intolerance (OI)

  • when lying down, the symptoms are improved, although not gone entirely (16), feel "almost well" while lying down
  • fatigue (2, 3, 14), exhaustion (16), tired, lack of energy
  • nausea (2, 3, 14)
  • lightheadedness (1, 2, 3, 7, 14, 16, 18)
  • heart palpitations (2)
  • sweating (2, 14)
  • fainting (1, 18, 29), sometimes passing out (2), brief loss of consciousness (7), syncope (1), blacking out
  • quickening heartbeat (7), heart rate increase (16)
  • trembling (7), tremors (14)
  • dizziness (1, 3, 14)
  • unsteadiness (3), swaying back and forth (16)
  • dimming or blurring of vision (3), visual disturbances (14)
  • weakness (3, 16)
  • cognitive impairment (3), inability to concentrate (16), inability to think clearly, forgetting what you are saying midsentence, being unable to read and follow a simple plot or idea, fuzzy head
  • head or neck discomfort (3), headaches (14)
  • breathing or swallowing difficulties (14)
  • pallor (14), paleness of the face
  • swollen, bluish legs, providing evidence of blood pooling in the lower part of the body (14), feet began to look purple (16), purple discoloration (18)
  • pain (16)
  • GI problems

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Compression Garments for Orthostatic Intolerance (OI)

There is research that shows successful use of compression garments at 40-50 mm Hg for Orthostatic Intolerance (OI) and Orthostatic Intolerance (OI) related illness. Compression garments can use air, such as a g-suit, MAST (Military/Medical Anti-Shock Trousers), inflatable pressure suit, and pneumatic (air) leg compression stockings or elastic, such as graduated leg compression stockings, support hose, girdles, and abdominal binders to provide pressure on the lower half of the body.

"The effective use of an air force anti-G suit in patients with postural hypotension has previously been described. A comparison between an air-filled suit (an experimental anti-G suit) and an elastic form of garment providing counterpressure showed that the air-filled suit was more effective in treating postural hypotension. As Burton has pointed out, the anti-G suit is not routinely used clinically to raise blood pressure, and it requires someone to suggest the role. The purpose of this paper is to draw attention to this clinical use of the anti-G suit." (19)

  • Orthostatic Intolerance (OI)
    • Orthostatic systolic hypotension - g-suit to 40 mm Hg (20), MAST, inflatable pressure suit to 45-50 mm Hg (8, 9, 13, 31, 32, 33), suggests corset or abdominal binder trial (20), compression stockings (18)
    • Orthostatic diastolic hypotension - inflatable pressure suit to 45-50 mm Hg (8)
    • Orthostatic diastolic hypertension - inflatable pressure suit to 45-50 mm Hg (8, 12)
    • Orthostatic narrowing of pulse pressure - inflatable pressure suit to 45-50 mm Hg (8)
    • Orthostatic postural tachycardia - MAST, inflatable pressure suit to 45-50 mm Hg (8, 13, 31, 33)
  • Chronic Fatigue Syndrome (CFS) - g-suit (34), MAST (16, 33), support hose, girdles (14, 35), abdominal binders (14), compression garments (11, 14, 35), compression stockings (18)
  • Shy-Drager Syndrome, Multiple System Atrophy (MSA), Progressive Autonomic Failure (PAF), progressive autonomic disorders - g-suit to 40 mm Hg (19, 20), suggests corset or abdominal binder trial (20)
  • Diabetes, diabetic autonomic neuropathy - g-suit 40-50 mm Hg (6, 20), suggests corset or abdominal binder trial (20), elastic stockings (22)
  • Tetraplegia, paraplegia - g-suit, lower body positive pressure suit, leg and abdominal pneumatic (air) devices (23)
  • Elderly - g-suit to 40 mm Hg (20), suggests corset or abdominal binder trial (20)
  • Parkinson's disease - compression stockings or abdominal binder (25)
  • Pheochromocytoma - MAST pressure suit to 45 mm Hg (13)
  • Dizziness, severe lightheadedness - decrease blood pooling in legs - special stockings, compression garment worn around the abdomen (36)
  • Chronic low blood pressure - keep blood in upper body - elastic support (compression) stockings that cover the calf and thigh (37)
  • Astronauts - g-suit (29, 30)
  • Fighter Pilots - g-suit

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Other Users of Compression Garments

  • Pulmonary Embolism and blood clot prevention - pneumatic (air) leg compression stockings (38, 39), graduated leg compression stockings (39, 40)
  • Venous Skin Ulcer prevention - compression stockings (41), graduated leg compression stockings (42)
  • Thrombophlebitis - treat blood clot problem in leg with supportive hose or stockings or leg wrapped (43)
    causes of Thrombophlebitis can include - Economy Class Syndrome, extensive bed rest after surgery, varicose veins, intravenous tubes (IV's), around childbirth, certain cancers, hormone estrogen, family history of blood clots (44)

See Frequently Asked Questions (FAQ) for other Orthostatic Intolerance treatments.

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Search Some of My Favorite Websites about Orthostatic Intolerance

Note: These search results will open in a new window.

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Note: "(on site)" means this information is available on this website through the link provided.
Links to resources outside of this website will open in a new window.

  1. WebMD. "Orthostatic hypotension", updated 5/27/2005: online WebMD - http://www.webmd.com/, 1/6/2006.
  2. David S. Bell, MD, FAAP. The Lyndonville Journal "Orthostatic Intolerance". (on site) Lyndonville News. May 2000, Volume 2, Issue 3.
  3. WebMD. "Hypotension - Introduction and Symptoms": online WebMD - http://www.webmd.com/, 6/1/2003.
  4. WebMD. "Understanding Low Blood Pressure - The Basics". Medically reviewed by Michael Aronson, MD, 7/2005: online WebMD - http://www.webmd.com/, 1/10/2006.
  5. The Pediatric Network - "Orthostatic Intolerance (OI)": online http://www.pediatricnetwork.org/medical/OI, 9/16/2005.
    [Note: As of May 2011, this website is not available.]
  6. Lori L. Elizondo, B.S., Donald F. Doerr, B.S.E.E., Mark A. Sims, M.D., G. Wyckliffe Hoffler, M.D., and Victor A. Convertino, Ph.D. "Application of USAF G-Suit Technology for Clinical Orthostatic Hypotension: A Case Study". (on site) Aviation, Space, and Environmental Medicine. Vol. 67, No. 4, April 1996, pages 344-350.
    Also available to view as PDF/Adobe Acrobat format. (1.6 MB) (on site)
  7. Jennifer Warner. "Space Research Eases Dizziness on Earth". WebMD Medical News 2/19/2002: online WebMD - http://www.webmd.com/, 6/1/2003.
  8. Streeten DH, Anderson GH Jr, Richardson R, Thomas FD. "Abnormal orthostatic changes in blood pressure and heart rate in subjects with intact sympathetic nervous function: evidence for excessive venous pooling". (abstract on site) J Lab Clin Med. March 1988, 111(3), pages 326-335.
    Department of Medicine, SUNY Health Science Center, Syracuse 13210.
  9. Streeten DH, Anderson GH Jr. "Delayed orthostatic intolerance". (abstract on site) Arch Intern Med. May 1992, 152(5), pages 1066-1072.
    Comment in: Arch Intern Med. May 1992, 152(5), page 919.
    Department of Medicine, State University of New York Health Science Center, Syracuse 13210.
  10. WebMD. "Hypotension, Orthostatic", updated 6/19/1997: online WebMD - http://www.webmd.com/, 6/1/2003.
  11. The CFIDS Association of America - http://www.cfids.org/ "Curriculum expands awareness - CFS: Primary Care Basics" (on site) Winter 2002: online http://www.cfids.org/archives/2002rr/2002-rr1-article01.asp, 7/26/2005.
  12. Streeten DH, Auchincloss JH Jr, Anderson GH Jr, Richardson RL, Thomas FD, Miller JW. "Orthostatic hypertension. Pathogenetic studies". (abstract on site) Hypertension. Mar-Apr 1985, 7(2), pages 196-203.
  13. Streeten DH, Anderson GH Jr. "Mechanisms of orthostatic hypotension and tachycardia in patients with pheochromocytoma". (abstract on site) Am J Hypertens. August 1996, 9(8), pages 760-769.
    Department of Medicine, State University of New York Health Science Center, Syracuse 13210, USA.
  14. The CFIDS Association of America - http://www.cfids.org/ "Diagnosis: Orthostatic Intolerance (OI)" (on site): online http://www.cfids.org/about-cfids/orthostatic-intolerance.asp, 7/26/2005.
  15. WebMD. "Chronic Fatigue Syndrome - Symptoms", updated 6/6/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  16. David S. Bell, MD, FAAP. Faces of CFS - Case Histories of Chronic Fatigue Syndrome. (on site) Lyndonville, New York: August 15, 2000. Chapter 9 "Andrea's Revolver", pages 71-74.
  17. The CFIDS Association of America - http://www.cfids.org/ "CFIDS Fact Sheet" (on site): online http://www.cfids.org/about-cfids/fact-sheet.asp, 12/2/2005.
  18. Dr. Richard L. Bruno. "Orthostatic Problems in CFIDS/FM and Post Polio Syndrome" - http://www.masscfids.org/main/update-2002-spring.html, The Massachusetts CFIDS/FM Association "Update" Spring 2002 Issue (48 pages): online Massachusetts CFIDS Association - http://www.masscfids.org, 7/5/2006.
    [Note: Article has moved to this page - http://www.masscfids.org/resource-library/3-research/60-orthostatic-problems-in-cfidsfm-and-post-polio-syndrome - May 2011.]
  19. Wilfrid H Brook RFD, MB, BS(Melb), MS(Mon), FRCSEd, FICA. "Postural hypotension and the anti-gravity suit". (on site) Australian Family Physician. Vol. 23, No. 10, October 1994, pages 1945-1949.
    Also available to view as PDF/Adobe Acrobat format. (1.5 MB) (on site)
  20. J.-C. Denq MD, T.L. Opfer-Gehrking, M. Giuliani MD, J. Felten, V.A. Convertino PhD, and P.A. Low MD. "Efficacy of compression of different capacitance beds in the amelioration of orthostatic hypotension". (on site) Clin Auton Res. Dec 1997, 7(6), pages 321-326.
    Also available to view as PDF/Adobe Acrobat format. (1.4 MB) (on site)
  21. WebMD. "Shy Drager Syndrome", updated 12/5/2000: online WebMD - http://www.webmd.com/, 6/1/2003.
  22. WebMD. "Diabetic Neuropathy - Treatment for blood pressure problems from diabetic neuropathy", updated 11/26/2002: online WebMD http://www.webmd.com/, 6/1/2003.
  23. Sarah A. Morrison, PT. "Chapter Three - Guidelines for the Clinician for Development of Fitness Programs for Individuals with Spinal Cord Injury" (on site). RRDS Physical Fitness: A Guide for Individuals with Spinal Cord Injury: online 9/28/02.
    Also available to view as PDF/Adobe Acrobat format. (3.9 MB) (on site)
  24. Kim Jones, PhD, RN, FNP. "Fibromyalgia: Treatment Update". WebMD Live Events Transcript 7/10/2003: online WebMD - http://www.webmd.com/, 7/26/2005.
  25. The Cleveland Clinic Movement Disorders Program, Department of Neurology. "From the Cleveland Clinic: Other Medical Concerns: Lightheadedness (Parkinson's)". Medically reviewed by Gary Vogin, MD, 10/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  26. WebMD. "Addison's Disease - Symptoms": online WebMD - http://www.webmd.com/, 1/6/2006.
  27. Tula Karras. "Mitral Valve Prolapse". WebMD Answers to Questions Archive 1999: online WebMD - http://www.webmd.com/, 1/6/2006.
  28. Gail Kansky. "Dr. Bell's New Research Based Theories" - http://www.ncf-net.org/forum/restheory.html, The National Forum: online The National CFIDS Foundation - http://www.ncf-net.org, 7/5/2006.
  29. Jeanie Lerche Davis. "Shuttle Reaps New Medical Data". WebMD Medical News Archive 12/6/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  30. Commission on Physical Sciences, Mathematics, and Applications (CPSMA) and Space Studies Board (SSB). A Strategy for Research in Space Biology and Medicine into the Next Century (1998) http://www.nap.edu/books/0309060478/html/ - chapter 8 Cardiovascular and Pulmonary Systems p.118 - Sections - Postflight Cardiovascular Physiology p.123, In-Flight Countermeasures p.124, and Future Directions p.125-6 with References 48-78 p.130-131: online 6/20/2001.
  31. Miller JW, Streeten DH. "Vascular responsiveness to norepinephrine in sympathicotonic orthostatic intolerance". (abstract on site) J Lab Clin Med. May 1990, 115(5), pages 549-558.
    Department of Medicine, State University of New York Health Science Center, Syracuse 13210.
  32. Streeten DH. "Pathogenesis of hyperadrenergic orthostatic hypotension. Evidence of disordered venous innervation exclusively in the lower limbs". (abstract on site) J Clin Invest. Nov 1990, 86(5), pages 1582-1588.
    Department of Medicine, State University of New York Health Science Center, Syracuse 13210.
  33. ImmuneSupport.com   "Tip of the Day" (on site) 1/10/2003: e-mail TipOfTheDay@prohealthinc.com, 1/10/2003.
  34. Dr. Peter Del Fante. "Response to CFS Clinical Practice Guidelines (Revised Draft 2001)". (excerpt on site) RACP Working Party - Chronic Fatigue Syndrome Project, 7/28/2001: online www.ahmf.org/g-delfante.html, 1/11/2003.
  35. The CFIDS Association of America - http://www.cfids.org/ "Orthostatic Intolerance and CFIDS Fact Sheet" (on site): online http://www.cfids.org/about-cfids/oi-and-cfs.asp, 7/26/2005.
  36. WebMD. "Understanding Dizziness - Detection & Treatment". Reviewed by Charlotte E. Grayson, MD, 4/2002: online WebMD - http://www.webmd.com/, 6/1/2003.
  37. WebMD, "Understanding Low Blood Pressure - Detection & Treatment". Medically reviewed by Michael Aronson, MD, 7/2005: online WebMD - http://www.webmd.com/, 1/23/2006.
  38. WebMD. "Pulmonary Embolism - Pneumatic leg compression stockings", updated 10/15/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  39. WebMD. "Pulmonary Embolism - Prevention", updated 10/15/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  40. WebMD. "Pulmonary Embolism - Graduated leg compression stockings for preventing blood clots", updated 10/15/2001: online WebMD - http://www.webmd.com/, 6/1/2003.
  41. WebMD. "Using compression stockings to prevent venous skin ulcer", updated 4/23/2002: online WebMD - http://www.webmd.com/, 6/1/2003.
  42. WebMD. "Venous Skin Ulcer - Compression stockings for preventing venous skin ulcer", updated 4/23/2002: online WebMD - http://www.webmd.com/, 6/1/2003.
  43. WebMD. "Understanding Thrombophlebitis - Detection & Treatment". Medically reviewed by Tracy Shuman, MD, 7/2005: online WebMD - http://www.webmd.com/, 1/23/2006.
  44. WebMD. "Understanding Thrombophlebitis - The Basics". Medically reviewed by Tracy Shuman, MD, 7/2005: online WebMD - http://www.webmd.com/, 1/23/2006.
  45. Ehlers-Danlos Syndrome Network - http://www.ehlersdanlosnetwork.org/index.html "EDS Hypermobility Type": online http://www.ehlersdanlosnetwork.org/hypermobility.html, 5/11/2011.
  46. Dysautonomia Information Network - http://www.dinet.org "What Causes POTS?": online http://www.dinet.org/what_causes_pots.htm, 5/11/2011.
    [Note: Article has moved to this page - http://www.dinet.org/index.php/information-resources/pots-place/pots-causes - May 2014.]

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