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| Name | Class |
|---|---|
| Biogen Extracts Pvt Ltd | UNKNOWN |
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Dietary inorganic nitrate supplementation may have positive implications on cardiovascular function. The aim of this project is to determine if nitrate supplementation can attenuate the effects that caffeine and cold exposure have on the cardiovascular system.
Acute caffeine consumption and cold exposure elicit negative effects on the cardiovascular system. Humans are regularly exposed to such conditions of increased cardiovascular strain, which may lead to elevated chronic cardiovascular risk. On the other hand, dietary inorganic nitrate supplementation is well established to improve cardiovascular function in healthy individuals. Thus, acute nitrate supplementation may compensate for the negative effects that caffeine and the cold place on the cardiovascular system. These effects will be measured using peripheral blood pressure, pulse wave analysis, heart rate variability, forearm blood flow, flow mediated dilation, and blood and saliva markers.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Nitrate, caffeine, and cold pressor test (CPT) | Experimental | All outcome variables will be measured for 24 participants in a trial where they receive 400 mg nitrate in the form of beetroot extract, 6 mg/kg caffeine powder, and undergo a 3 min cold pressor test. |
|
| Nitrate, placebo caffeine, and CPT | Placebo Comparator | All outcome variables will be measured for 24 participants in a trial where they receive 400 mg nitrate in the form of beetroot extract, 6 mg/kg cornflour (caffeine placebo), and undergo a 3 min cold pressor test. |
|
| Placebo nitrate, caffeine, and CPT | Placebo Comparator | All outcome variables will be measured for 24 participants in a trial where they receive nitrate-depleted beetroot extract (placebo), 6 mg/kg caffeine powder, and undergo a 3 min cold pressor test. |
|
| Placebo nitrate, placebo caffeine, and CPT | Placebo Comparator | All outcome variables will be measured for 24 participants in a trial where they receive nitrate-depleted beetroot extract (placebo), 6 mg/kg cornflour (caffeine placebo), and undergo a 3 min cold pressor test. |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| TruBeet inorganic beetroot juice | Dietary Supplement | 400 mg nitrate-rich beetroot powder, mixed with 300 mL water. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Brachial blood pressure | Brachial blood pressure was collected using an automatic sphygmomanometer. | Mean of 5 readings taken pre-supplementation (0 hours) and post-supplementation (2.5 hours). 1 reading was taken pre- cold pressor test (3.5 hours). All measures were recorded on every experimental trial (4 trials with at least 48 h washout between). |
| Flow mediated dilation | Baseline diameter, peak diameter, change in diameter, and shear stimulus following flow mediated dilation procedure of the brachial artery with post-occlusion reactive hyperaemia. | Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between). |
| Central blood pressure and pulse wave variables | Mean of 2-3 readings for aortic systolic BP, aortic diastolic BP, HR, Augmentation index, augmentation index corrected to HR of 75 bpm, pulse pressure, and augmentation pressure. | Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between). |
| Measure | Description | Time Frame |
|---|---|---|
| Forearm blood flow | Forearm blood flow pre- and post-PORH (post occlusion reactive hyperaemia) via strain gauge plethysmography. | Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between). |
| Salivary nitrate and nitrite |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Stephen Bailey | Loughborough University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Loughborough University | Loughborough | LE11 3TU | United Kingdom |
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| ID | Term |
|---|---|
| D002110 | Caffeine |
| ID | Term |
|---|---|
| D014970 | Xanthines |
| D000470 | Alkaloids |
| D006571 | Heterocyclic Compounds |
| D011688 | Purinones |
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24 participants will complete 4 experimental conditions in a randomized order.
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Double-blinded using supplement placebos.
| Caffeine | Dietary Supplement | 6 mg/kg caffeine powder in capsule form. |
|
| Cold pressor test | Other | 3 min cold pressor test using the left foot in cold water (0-2 degree). |
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Salivary concentration of nitrate and nitrite |
| Measured pre-supplementation (at 0 hours) and post-supplementation (at 2.5 hours) for every experimental trial (4 trials with at least 48 h washout between). |
| Heart rate variability | Time and frequency domains for heart rate variability collected for 3-5min. | Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between). |
| NIBP continuous blood pressure | SBP, DBP, MAP, HR collected continuously for 3-5 min. | Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and during the cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between). |
| Whole blood RSNO | S--nitrosothiols concentration from treated whole blood (NEM, EDTA, potassium ferricyanide). | Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and immediately post- cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between). |
| Plasma nitrate, nitrite, cGMP | Plasma concentrations of nitrate, nitrite, and cGMP. | Collected pre-supplementation (0 hours), post-supplementation (2.5 hours), and immediately post- cold pressor test (3.5 h) for 4 experimental trials (4 trials with at least 48 hours washout in between) |
| D011687 |
| Purines |
| D006574 | Heterocyclic Compounds, 2-Ring |
| D000072471 | Heterocyclic Compounds, Fused-Ring |