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The purpose of this trial is to investigate the effect of acute ketone monoester ingestion (0.6 g KME/kg body weight) on the occurrence of the ventilatory threshold and the subsequent response of blood velocity in cerebral arteries during a maximal exercise test at low altitude and high altitude.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| High Altitude (3800m; Barcroft Research Station) | Experimental | High altitude setting |
|
| Low Altitude (334m; University of Guelph) | Experimental | Low altitude setting |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Ketone Monoester (KME) | Dietary Supplement | 0.6 g KME per kg body mass; [R]-3-hydroxybutyl [R]-3-hydroxybutyrate. (Delta G Ketone, TΔS, Oxford). |
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| Measure | Description | Time Frame |
|---|---|---|
| Cerebral Blood Velocity | Transcranial Doppler ultrasound will be used to measure blood velocity in the middle cerebral artery and posterior cerebral artery. Location of measurements will remain consistent within participants. | 3 hours |
| Measure | Description | Time Frame |
|---|---|---|
| Cardiac Output | Cardiac output (L/min) will be measured using a non-invasive cardiac output monitor (Physioflow). The monitor uses signal morphology impedance cardiography to determine cardiac output. | 3 hours |
| Blood Pressure |
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Inclusion Criteria:
- Must be a member of the research expedition team travelling to the Barcroft Research Station in White Mountain California
Exclusion Criteria:
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Barcroft Research Station | Recruiting | Bishop | California | 93514 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 11689733 | Background | Gaskill SE, Ruby BC, Walker AJ, Sanchez OA, Serfass RC, Leon AS. Validity and reliability of combining three methods to determine ventilatory threshold. Med Sci Sports Exerc. 2001 Nov;33(11):1841-8. doi: 10.1097/00005768-200111000-00007. |
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| ID | Term |
|---|---|
| D009043 | Motor Activity |
| ID | Term |
|---|---|
| D001519 | Behavior |
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| Placebo | Dietary Supplement | Inert, calorie-free placebo drink that is taste-matched to the ketone monoester supplement |
|
Mean arterial pressure (mmHg) will be measured via a brachial cuff placed on the upper arm.
| 3 hours |
| Ventilatory Threshold | Ventilatory threshold (VT) will be calculated based on previously described methods (Gaskill et al., 2001). | 3 hours |
| End-Tidal Gases | End-tidal oxygen (PETO2) (mmHg) and carbon dioxide (PETCO2) (mmHg) will be collected using a metabolic cart. | 3 hours |
| Rate of Oxygen Consumption and Carbon Dioxide Production | Rate of oxygen consumption (VO2) (mL/min) and carbon dioxide production (VCO2) (mL/min) will be collected using a metabolic cart. | 3 hours |
| Ventilation | Ventilation (Ve) (L/min) will be collected using a metabolic cart. | 3 hours |
| Blood Lactate and Beta-Hydroxybutyrate | Capillary blood will be obtained via finger prick using a lancing device to measure concentrations of blood lactate (mmol/L) and beta-hydroxybutyrate (mmol/L) using a handheld metabolite analyzer. | 3 hours |
| Peak Work Rate (Maximal Exercise Test) | The maximum wattage (W) achieved by the participant during the maximal exercise test will be recorded. | 3 hours |
| University of Guelph | Recruiting | Guelph | Ontario | N1G 2W1 | Canada |
|