Orthostatic HypotensionNCT05621460
The Effect of Water Carbonation on Orthostatic Tolerance
A study testing 500mL carbonated water, 500mL still water and 50mL still water in people with Orthostatic Hypotension and Syncope, run by Simon Fraser University at 1 site in Canada.
Trial summary
The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. Read more about this study
- Who is it for?
- Ages 19 to 50 yearsHealthy volunteers can take part
- Conditions the study is for
- Orthostatic Hypotension, Syncope, Vasovagal Syncope
- What is being tested?
- 500mL carbonated water, 500mL still water and 50mL still water
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 25 participants
- Where
- 1 siteCanada
- Study dates
- 1 Sep 2023to Apr 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 19 to 50 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- healthy, English-speaking
Who cannot join
- pregnancy or suspected pregnancy, history of cardiovascular disease, history of neurological disease, history of recurrent fainting (≥ 2 episodes of fainting with loss of consciousness in the prior 6 months)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
Simon Fraser University
Burnaby, British Columbia, V5A 1S6
Vera-Ellen M Lucci, PhD, 7787828560, vlucci@sfu.ca
Victoria E Claydon, PhD
About this study
The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes. Drinking water can boost blood pressure and making fainting episodes less likely. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.
Read the detailed description
The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing [1]. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes [1]. Drinking water can boost blood pressure and making fainting episodes less likely [2-8]. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response [9,10]. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.
Volunteers (n=25) will be asked to undergo a "tilt test" to assess cardiovascular reflex control and orthostatic tolerance (measured as time to presyncope, or near fainting, in minutes). It has been previously shown that this technique to be reproducible, reliable, and to have high sensitivity and specificity for differentiating persons with differing orthostatic tolerance, or for examining the effects of interventions aimed at improving orthostatic tolerance [4,6,11-18].
Volunteers will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50ml drink of room temperature water (control condition), a 500ml drink of flat (non-carbonated) room temperature water, or a 500ml drink of carbonated room temperature water. The study will be conducted in a randomised, single-blind fashion. The investigator responsible for terminating the test will be blinded as to the water condition on each test day, rendering the study single blind. It will not be possible to blind participants as to the carbonation of the water, however, participants will not be informed as to the hypothesised impact of the water conditions.
- Conditions
- Orthostatic Hypotension, Syncope, Vasovagal Syncope
- Being tested
- 500mL carbonated water, 500mL still water, 50mL still water
- Keywords
- Tilt table, Osmopressor reflex, Gastropressor reflex
- Medical subject headings
- Hypotension, Orthostatic, Syncope, Syncope, Vasovagal
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
500mL carbonated waterOther
Drink 500mL carbonated water immediately prior to head-up tilt test
500mL still waterOther
Drink 500mL still water immediately prior to head-up tilt test
50mL still waterOther
Drink 50mL still water immediately prior to head-up tilt test
| Study group | Role | What they receive |
|---|---|---|
| 500mL carbonated water first, then 500mL of still water, then 50mL of still water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL carbonated water on the first test day, 500mL still water on the second test day, then 50mL still water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
| 500mL still water first, then 500 mL carbonated water, then 50mL still water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL still water on the first test day, 500mL carbonated water on the second test day, then 50mL still water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
| 500mL carbonated water first, then 50mL of still water, then 500mL of still water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL carbonated water on the first test day, 50mL still water on the second test day, then 500mL still water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
| 500mL still water first, then 50mL still water, then 500 mL carbonated water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL still water on the first test day, 50mL still water on the second test day, then 500mL carbonated water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
| 50mL still water first, then 500mL still water, then 500 mL carbonated water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 50mL still water on the first test day, 500mL carbonated water on the second test day, then 500mL carbonated water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
| 50mL still water first, then 500mL carbonated water, then 500 mL still water | Experimental | Participants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 50mL still water on the first test day, 500mL still water on the second test day, then 500mL still water on the third day. Receives: Other: 500mL carbonated water; Other: 500mL still water; Other: 50mL still water |
What is being measured
The primary outcome is the main question the study is designed to answer.
Orthostatic tolerance
The time, in minutes, to presyncope (near-fainting) after the initiation of head-up tilt
Measured: 0-50 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Nov 2022
- Study start1 Sep 2023
- Primary completionApr 2027 (estimated)
- Study completionApr 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (18)Papers the sponsor has linked to this study.
- Other trials for Orthostatic HypotensionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Each participant will complete the test for every condition (3 tests per participant, order of treatment randomized).
- Masking
- Single blind
- Who is masked
- Investigator
- Enrolment
- 25 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Simon Fraser University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Dr. Victoria Claydon, Simon Fraser University
- Investigators
- Victoria E Claydon, PhD, Principal investigator, Professor, Biomedical Physiology and Kinesiology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05621460
- Sponsor's protocol ID
- 30000955
- Status last verified
- Apr 2026
- First submitted
- 10 Nov 2022
- Last updated
- 23 Apr 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Data will be presented in aggregate form and no identifiers will be included.
Publications
Hainsworth R, Claydon V E. Syncope and fainting: classification and physiological basis. In: Bannister R, Mathias CJ, eds. Autonomic failure: a textbook of clinical disorders of the autonomic nervous system. Oxford: Oxford University Press, 2006
Mathias CJ. A 21st century water cure. Lancet. 2000 Sep 23;356(9235):1046-8. doi: 10.1016/S0140-6736(00)02723-9.
PubMed 11009136Mathias CJ, Young TM. Water drinking in the management of orthostatic intolerance due to orthostatic hypotension, vasovagal syncope and the postural tachycardia syndrome. Eur J Neurol. 2004 Sep;11(9):613-9. doi: 10.1111/j.1468-1331.2004.00840.x.
PubMed 15379740Schroeder C, Bush VE, Norcliffe LJ, Luft FC, Tank J, Jordan J, Hainsworth R. Water drinking acutely improves orthostatic tolerance in healthy subjects. Circulation. 2002 Nov 26;106(22):2806-11. doi: 10.1161/01.cir.0000038921.64575.d0.
PubMed 12451007Brown CM, Barberini L, Dulloo AG, Montani JP. Cardiovascular responses to water drinking: does osmolality play a role? Am J Physiol Regul Integr Comp Physiol. 2005 Dec;289(6):R1687-92. doi: 10.1152/ajpregu.00205.2005. Epub 2005 Jul 21.
PubMed 16037127Claydon VE, Schroeder C, Norcliffe LJ, Jordan J, Hainsworth R. Water drinking improves orthostatic tolerance in patients with posturally related syncope. Clin Sci (Lond). 2006 Mar;110(3):343-52. doi: 10.1042/CS20050279.
PubMed 16321141Lu CC, Diedrich A, Tung CS, Paranjape SY, Harris PA, Byrne DW, Jordan J, Robertson D. Water ingestion as prophylaxis against syncope. Circulation. 2003 Nov 25;108(21):2660-5. doi: 10.1161/01.CIR.0000101966.24899.CB. Epub 2003 Nov 17.
PubMed 14623807Boschmann M, Steiniger J, Hille U, Tank J, Adams F, Sharma AM, Klaus S, Luft FC, Jordan J. Water-induced thermogenesis. J Clin Endocrinol Metab. 2003 Dec;88(12):6015-9. doi: 10.1210/jc.2003-030780.
PubMed 14671205May M, Jordan J. The osmopressor response to water drinking. Am J Physiol Regul Integr Comp Physiol. 2011 Jan;300(1):R40-6. doi: 10.1152/ajpregu.00544.2010. Epub 2010 Nov 3.
PubMed 21048076Jordan J, Shannon JR, Black BK, Ali Y, Farley M, Costa F, Diedrich A, Robertson RM, Biaggioni I, Robertson D; New Collective Author. The pressor response to water drinking in humans : a sympathetic reflex? Circulation. 2000 Feb 8;101(5):504-9. doi: 10.1161/01.cir.101.5.504.
PubMed 10662747Al Shamma YMA, Hainsworth R. A quantitative comparison of the circulatory responses in humans to graded upright tilting and graded lower body negative pressure. Cardiogenic Reflexes (1987):431-432.
Brown CM, Hainsworth R. Forearm vascular responses during orthostatic stress in control subjects and patients with posturally related syncope. Clin Auton Res. 2000 Apr;10(2):57-61. doi: 10.1007/BF02279892.
PubMed 10823336Bush VE, Wight VL, Brown CM, Hainsworth R. Vascular responses to orthostatic stress in patients with postural tachycardia syndrome (POTS), in patients with low orthostatic tolerance, and in asymptomatic controls. Clin Auton Res. 2000 Oct;10(5):279-84. doi: 10.1007/BF02281110.
PubMed 11198483Claydon VE, Hainsworth R. Salt supplementation improves orthostatic cerebral and peripheral vascular control in patients with syncope. Hypertension. 2004 Apr;43(4):809-13. doi: 10.1161/01.HYP.0000122269.05049.e7. Epub 2004 Feb 23.
PubMed 14981050Claydon VE, Hainsworth R. Cerebral autoregulation during orthostatic stress in healthy controls and in patients with posturally related syncope. Clin Auton Res. 2003 Oct;13(5):321-9. doi: 10.1007/s10286-003-0120-8.
PubMed 14564654
Study at a glance
From the registry record, last updated by the sponsor on 23 Apr 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Effect of Water Carbonation on Orthostatic Tolerance
- ClinicalTrials.gov ID
- NCT05621460
- Acronym / sponsor ID
- 30000955
- Conditions
- Orthostatic Hypotension, Syncope, Vasovagal Syncope
- Keywords
- Tilt table, Osmopressor reflex, Gastropressor reflex
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 25 participants (estimated)
- Lead sponsor
- Simon Fraser UniversityUniversity, hospital or other
- Study start
- 1 Sep 2023 (actual)
- Primary completion
- Apr 2027 (estimated)
- Study completion
- Apr 2027 (estimated)
- First posted
- 18 Nov 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes. Drinking water can boost blood pressure and making fainting episodes less likely. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.
Detailed description
The primary purpose of this investigation is to determine whether water carbonation can improve orthostatic tolerance in healthy control volunteers. Orthostatic tolerance refers to the ability to maintain an adequate blood pressure when standing [1]. In some individuals blood pressure can fall when standing, predisposing to dizzy spells or fainting episodes [1]. Drinking water can boost blood pressure and making fainting episodes less likely [2-8]. However, it is not clear whether the carbonation of the water has any further impact on the blood pressure response [9,10]. This is important because it may be that carbonated water expands the stomach (gastric distension), provoking an increase in sympathetic activity. The increase in sympathetic nervous system activity boosts blood pressure. Resolving this question would have important implications for patients with syncope. This study will test whether carbonated water will have any further impact on blood pressure than the already known effect of non-carbonated water.
Volunteers (n=25) will be asked to undergo a "tilt test" to assess cardiovascular reflex control and orthostatic tolerance (measured as time to presyncope, or near fainting, in minutes). It has been previously shown that this technique to be reproducible, reliable, and to have high sensitivity and specificity for differentiating persons with differing orthostatic tolerance, or for examining the effects of interventions aimed at improving orthostatic tolerance [4,6,11-18].
Volunteers will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50ml drink of room temperature water (control condition), a 500ml drink of flat (non-carbonated) room temperature water, or a 500ml drink of carbonated room temperature water. The study will be conducted in a randomised, single-blind fashion. The investigator responsible for terminating the test will be blinded as to the water condition on each test day, rendering the study single blind. It will not be possible to blind participants as to the carbonation of the water, however, participants will not be informed as to the hypothesised impact of the water conditions.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (investigator)
- Number of arms
- 6
- Model description
- Each participant will complete the test for every condition (3 tests per participant, order of treatment randomized).
| Arm | Type | Receives |
|---|---|---|
| 500mL carbonated water first, then 500mL of still water, then 50mL of still water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL carbonated water on the first test day, 500mL still water on the second test day, then 50mL still water on the third day. |
| 500mL still water first, then 500 mL carbonated water, then 50mL still water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL still water on the first test day, 500mL carbonated water on the second test day, then 50mL still water on the third day. |
| 500mL carbonated water first, then 50mL of still water, then 500mL of still water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL carbonated water on the first test day, 50mL still water on the second test day, then 500mL still water on the third day. |
| 500mL still water first, then 50mL still water, then 500 mL carbonated water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 500mL still water on the first test day, 50mL still water on the second test day, then 500mL carbonated water on the third day. |
| 50mL still water first, then 500mL still water, then 500 mL carbonated water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 50mL still water on the first test day, 500mL carbonated water on the second test day, then 500mL carbonated water on the third day. |
| 50mL still water first, then 500mL carbonated water, then 500 mL still water | Experimental | Other: 500mL carbonated water, Other: 500mL still water, Other: 50mL still waterParticipants will undergo this test on three separate days. On each day participants will be asked to drink a glass of water: either a 50mL drink of still water (control condition), a 500mL drink of still (non-carbonated) water, or a 500mL drink of carbonated water. In this arm of the study, participants will receive 50mL still water on the first test day, 500mL still water on the second test day, then 500mL still water on the third day. |
Who may qualify
- Ages
- 19 to 50 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- healthy, English-speaking
Key exclusion criteria (1 listed)
- pregnancy or suspected pregnancy, history of cardiovascular disease, history of neurological disease, history of recurrent fainting (≥ 2 episodes of fainting with loss of consciousness in the prior 6 months)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 500mL carbonated waterDrink 500mL carbonated water immediately prior to head-up tilt test | Other | 500mL carbonated water first, then 500mL of still water, then 50mL of still water, 500mL carbonated water first, then 50mL of still water, then 500mL of still water, 500mL still water first, then 500 mL carbonated water, then 50mL still water, 500mL still water first, then 50mL still water, then 500 mL carbonated water, 50mL still water first, then 500mL carbonated water, then 500 mL still water, 50mL still water first, then 500mL still water, then 500 mL carbonated water |
| 500mL still waterDrink 500mL still water immediately prior to head-up tilt test | Other | 500mL carbonated water first, then 500mL of still water, then 50mL of still water, 500mL carbonated water first, then 50mL of still water, then 500mL of still water, 500mL still water first, then 500 mL carbonated water, then 50mL still water, 500mL still water first, then 50mL still water, then 500 mL carbonated water, 50mL still water first, then 500mL carbonated water, then 500 mL still water, 50mL still water first, then 500mL still water, then 500 mL carbonated water |
| 50mL still waterDrink 50mL still water immediately prior to head-up tilt test | Other | 500mL carbonated water first, then 500mL of still water, then 50mL of still water, 500mL carbonated water first, then 50mL of still water, then 500mL of still water, 500mL still water first, then 500 mL carbonated water, then 50mL still water, 500mL still water first, then 50mL still water, then 500 mL carbonated water, 50mL still water first, then 500mL carbonated water, then 500 mL still water, 50mL still water first, then 500mL still water, then 500 mL carbonated water |
Primary outcome
Orthostatic tolerance
Time frame: 0-50 minutes
The time, in minutes, to presyncope (near-fainting) after the initiation of head-up tilt
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Apr 2026.
- BackgroundHainsworth R, Claydon V E. Syncope and fainting: classification and physiological basis. In: Bannister R, Mathias CJ, eds. Autonomic failure: a textbook of clinical disorders of the autonomic nervous system. Oxford: Oxford University Press, 2006
- Background: PubMed 11009136Mathias CJ. A 21st century water cure. Lancet. 2000 Sep 23;356(9235):1046-8. doi: 10.1016/S0140-6736(00)02723-9.
- Background: PubMed 15379740Mathias CJ, Young TM. Water drinking in the management of orthostatic intolerance due to orthostatic hypotension, vasovagal syncope and the postural tachycardia syndrome. Eur J Neurol. 2004 Sep;11(9):613-9. doi: 10.1111/j.1468-1331.2004.00840.x.
- Background: PubMed 12451007Schroeder C, Bush VE, Norcliffe LJ, Luft FC, Tank J, Jordan J, Hainsworth R. Water drinking acutely improves orthostatic tolerance in healthy subjects. Circulation. 2002 Nov 26;106(22):2806-11. doi: 10.1161/01.cir.0000038921.64575.d0.
- Background: PubMed 16037127Brown CM, Barberini L, Dulloo AG, Montani JP. Cardiovascular responses to water drinking: does osmolality play a role? Am J Physiol Regul Integr Comp Physiol. 2005 Dec;289(6):R1687-92. doi: 10.1152/ajpregu.00205.2005. Epub 2005 Jul 21.
- Background: PubMed 16321141Claydon VE, Schroeder C, Norcliffe LJ, Jordan J, Hainsworth R. Water drinking improves orthostatic tolerance in patients with posturally related syncope. Clin Sci (Lond). 2006 Mar;110(3):343-52. doi: 10.1042/CS20050279.
- Background: PubMed 14623807Lu CC, Diedrich A, Tung CS, Paranjape SY, Harris PA, Byrne DW, Jordan J, Robertson D. Water ingestion as prophylaxis against syncope. Circulation. 2003 Nov 25;108(21):2660-5. doi: 10.1161/01.CIR.0000101966.24899.CB. Epub 2003 Nov 17.
- Background: PubMed 14671205Boschmann M, Steiniger J, Hille U, Tank J, Adams F, Sharma AM, Klaus S, Luft FC, Jordan J. Water-induced thermogenesis. J Clin Endocrinol Metab. 2003 Dec;88(12):6015-9. doi: 10.1210/jc.2003-030780.
- Background: PubMed 21048076May M, Jordan J. The osmopressor response to water drinking. Am J Physiol Regul Integr Comp Physiol. 2011 Jan;300(1):R40-6. doi: 10.1152/ajpregu.00544.2010. Epub 2010 Nov 3.
- Background: PubMed 10662747Jordan J, Shannon JR, Black BK, Ali Y, Farley M, Costa F, Diedrich A, Robertson RM, Biaggioni I, Robertson D; New Collective Author. The pressor response to water drinking in humans : a sympathetic reflex? Circulation. 2000 Feb 8;101(5):504-9. doi: 10.1161/01.cir.101.5.504.
- BackgroundAl Shamma YMA, Hainsworth R. A quantitative comparison of the circulatory responses in humans to graded upright tilting and graded lower body negative pressure. Cardiogenic Reflexes (1987):431-432.
- Background: PubMed 10823336Brown CM, Hainsworth R. Forearm vascular responses during orthostatic stress in control subjects and patients with posturally related syncope. Clin Auton Res. 2000 Apr;10(2):57-61. doi: 10.1007/BF02279892.
- Individual participant dataSharing planned: No. Data will be presented in aggregate form and no identifiers will be included.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Victoria E Claydon, PhD principal investigator
Professor, Biomedical Physiology and Kinesiology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing 500mL carbonated water, 500mL still water and 50mL still water in people with Orthostatic Hypotension and Syncope, run by Simon Fraser University at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Apr 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Victoria E Claydon, PhD (7787828513, victoria_claydon@sfu.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Orthostatic tolerance (time frame: 0-50 minutes). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05621460, which also lists 18 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Apr 2026.