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Additional Short Research

More examples of the use of pressure garments (g-suit, MAST) for Orthostatic Intolerance (OI).

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Military Anti-Shock Trousers (MAST) and Chronic Fatigue Syndrome (CFS)/Orthostatic Intolerance (OI)

People with Chronic Fatigue Syndrome (CFS) often show low blood pressure readings, especially after standing from a sitting position. A New York state study found that 15 CFS patients had significantly lower (p<0.0001) systolic (heart pumping) and diastolic (heart filling) blood pressure than 15 health-matched controls. Standing heart rates were significantly increased in the CFS patients (p<0.01).

When 11 of these patients wore Military Anti Shock Trousers (MAST), which increased blood pressure on their legs and moved blood up to the brain, 10 patients (91%) reported improvement of their CFS symptoms.

In addition, red blood cell volume was significantly decreased in plasma and norepinephrine levels were significantly higher in the CFS patients. Low blood pressure, especially in the brain, can cause fatigue and lack of concentration. Another study published in JAMA (1985; 274:961-7) noted that many CFS patients with low pressure reported reduction in symptoms when given a diet high in water and sodium.

(Source: Tired - So Tired and the 'Yeast Connection' by William G. Crook, M.D.)

From - ImmuneSupport.com - Tip of the Day for January 10, 2003

Copyright © 2003, ImmuneSupport.com

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G-suit and Chronic Fatigue Syndrome (CFS)/Orthostatic Intolerance (OI)

#16 With regards to the orthostatic intolerance symptoms I have now trialled a treatment with four patients using a pressure garment (an RAAF [Royal Australian Air Force] G-suit - lower body garment). All have reported huge relief of symptoms in relation to 'brain fog', neuro-cognitive dysfunction, headaches, and inability to sit or stand for even brief periods. My current patient is now (for the first time in 4 years) able to get stuck into her Year 12 studies, and doing extremely well. Read more.

From - RACP Guidelines for CFS - Response to CFS Clinical Practice Guidelines (Revised Draft 2001) Dr. Peter Del Fante July 28, 2001 - www.ahmf.org/g-delfante.html
[Note: As of 2024, this website is not available.]

Copyright © 2001 Dr. Peter Del Fante

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Pressure garments and Chronic Fatigue Syndrome (CFS)/Orthostatic Intolerance (OI)

Page 10 Orthostatic intolerance (low blood pressure/resting tachycardia) Pressure garments on lower limbs and abdomen might also help ambulation. Read more. (PDF/Adobe Acrobat format -110 KB - on site)

From - Myalgic Encephalopathy (ME)/Chronic Fatigue Syndrome (CFS) Management Guidelines for General Practitioners - A guideline for the diagnosis and management of ME/CFS in the community or primary care setting - South Australian guidelines 6/2004

See Links for more information.

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Astronauts also use G-suits for Orthostatic Intolerance (OI)

Most astronauts experience Orthostatic Intolerance (OI) when they return to earth from space. The section Postflight Cardiovascular Physiology explains Orthostatic Intolerance (OI) and tests that show some of the ways it affects astronauts' bodies. The section In-Flight Countermeasures explains ways astronauts have tried to reduce the effects of Orthostatic Intolerance (OI) which includes the use of anti-g garments. The section Future Directions expresses the importance of Orthostatic Intolerance (OI) as a problem for astronauts and the need for further work in solving the problem. Read more.

From the publication: A Strategy for Research in Space Biology and Medicine into the Next Century (1998) - http://www.nap.edu/books/0309060478/html/ by Commission on Physical Sciences, Mathematics, and Applications (CPSMA) and Space Studies Board (SSB)
From 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

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Effect of G-Suit Protection on Carotid-Cardiac Baroreflex Function

Victor A. Convertino, Ph.D., and Craig A. Reister, M.S.

Aviat Space Environ Med 2000; 71:31-6


Introduction: To test the hypothesis that G-suit inflation could increase cardiac chronotropic responses to baroreceptor stimulation and enhance baroreflex buffering of BP [blood pressure], the carotid-cardiac baroreflex response of 12 subjects was measured across two levels of lower body negative pressure (LBNP = 0 and 50 mmHg) and two levels of G-suit inflation (0 and 50 mmHg) in random order. Methods: Carotid-cardiac baroreflex stimulation was delivered via a silastic neck pressure cuff and responsiveness quantified by determination of the maximum slope of the stimulus-response function between R-R intervals (ms) and their respective carotid distending pressures (mmHg). Results: Mean ± SE baseline control baroreflex responsiveness was 3.8 ± 0.4 ms centered dot mmHg-1. LBNP reduced the baroreflex response to 2.7 ± 0.4 ms centered dot mmHg-1, but G-suit inflation with LBNP restored the baroreflex response to 4.3 ± 0.6 ms centered dot mmHg-1. Conclusions: These results suggest that, in addition to increased venous return and elevated peripheral resistance, G-suit inflation may provide protection against the debilitating effects of blood distribution to the lower extremities during orthostatic challenges such as standing or high +Gz acceleration by increasing cardiovascular responsiveness to carotid baroreceptor stimulation.

Copyright © 2000 Victor A. Convertino, Ph.D.

Posted with permission from the author.

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Blood Pressure Changes during Orthostatic Stress: Evidence of Gender Differences in Neuroeffector Distribution

David A. Ludwig, Ph.D., Joan Vernikos, Ph.D., Charles E. Wade, Ph.D., and Victor A. Convertino, Ph.D.

Aviat Space Environ Med 2001; 72:892-8


Background: Research has demonstrated that exogenous adrenergic agonists produce dose-related vasoconstriction in men but not women. This suggests that the distribution of adrenergic receptor sites differ with gender. Women may have a higher density of receptor sites in the arterioles (fast acting with low gain) while men may have higher density in the larger vessels (slow acting with high gain). Methods: To partially test this hypothesis, the time course in beat-to-beat responses in systolic and diastolic BP [blood pressure], and heart rate was compared between six men and six women during the transition from a supine to an upright posture and during prolonged standing. Results: The transient change in systolic and diastolic BP was very rapid in women, but completed within 15 to 30 s after assuming an upright position. Men increased BP at a much slower rate, but continued to produce higher BPs over the complete testing session (up to 15 min). The rate of change for men (15 mm Hg systolic and 10 mm Hg diastolic) was approximately half that for women (30 mm Hg systolic and 15 mm Hg diastolic) during the first 30 s of upright posture. However, after 60 s of standing, absolute change in systolic BP for the men exceeded that of the women by approximately 5 mm Hg for both systolic and diastolic BP. While men's heart rate remained relatively constant during standing, women compensated for the lower change in BP by a continual increase in heart rate throughout the duration of the test. Although both men and women demonstrated increases in norepinephrine at 5 and 15 min during standing, no difference between genders was observed. Similarly, there were no differences in dominant periodicity of heart rate during standing, although women demonstrated slightly higher beat-to-beat variation (RMS) than men. Conclusion: The results support the hypothesis of distributional differences in neuroeffector responses between men and women and have implications for how men and women respond to orthostatic stress across a variety of environmental conditions.

Copyright © 2001 Victor A. Convertino, Ph.D.

Posted with permission from the author.

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Information in brackets has been added.


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