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| Name | Class |
|---|---|
| University College, London | OTHER |
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Assess the effects of adding theanine to a caffeinated beverage on changes in blood pressure during acute mental stress.
Caffeine and (mental) stress can increase blood pressure. In a typical everyday and/or work environment they commonly coincide. Tea has the reputation of being a relaxing drink. L-theanine is an amino acid found almost exclusively in tea. In a previous study it was shown that caffeine increased blood pressure, while theanine antagonised these effects. In the current study the effect of theanine to a placebo on blood pressure are directly compared.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Combination of caffeine and theanine | Experimental | 250 mg caffeine + 200 mg theanine |
|
| Caffeine | Placebo Comparator | 250 mg caffeine |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Combination of caffeine and theanine | Other | Beverage containing caffeine and theanine |
|
| Measure | Description | Time Frame |
|---|---|---|
| Systolic blood pressure during stress | Systolic blood pressure during acute mental stress | Between 30-45 minutes after test product intake |
| Measure | Description | Time Frame |
|---|---|---|
| Diastolic blood pressure during stress | Diastolic blood pressure during acute mental stress | Between 30-45 minutes after test product intake |
| Systolic blood pressure after stress | Systolic blood pressure immediately after acute mental stress |
| Measure | Description | Time Frame |
|---|---|---|
| Cortisol in saliva before and immediately after stress | Concentration of cortisol in saliva | -5, 45 min relative to test product intake |
| Heart rate during stress | Heart rate during acute mental stress |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Mark Hamer, Dr | UCL, Epidemiology & Public Health, London | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University College London | London | United Kingdom |
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| ID | Term |
|---|---|
| C026166 | theanine |
| D002110 | Caffeine |
| ID | Term |
|---|---|
| D014970 | Xanthines |
| D000470 | Alkaloids |
| D006571 | Heterocyclic Compounds |
| D011688 | Purinones |
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| Caffeine | Other | Beverage containing caffeine |
|
| Between 45-60 minutes after test product intake |
| Diastolic blood pressure after stress | Diastolic blood pressure immediately after acute mental stress | Between 45-60 minutes after test product intake |
| STAI before and immediately after stress | Self-reported mental state: State-Trait Anxiety Inventory | -15 and 45 relative to test product intake |
| UWIST before and immediately after stress | Self-reported mental state: University Of Wales Institute of Science and Technology mood adjective questionnaire | -10, 45 minutes relative to test product intake |
| Between 30-45 minutes after test product intake |
| Heart rate after stress | Heart rate immediately after acute mental stress | Between 45-60 minutes after test product intake |
| Heart rate variability during stress | Heart rate variability during acute mental stress | Between 30-45 minutes after test product intake |
| Heart rate variability after stress | Heart rate variability immediately after acute mental stress | Between 45-60 minutes after test product intake |
| Performance STROOP | Task performance on STROOP task | Between 30-45 minutes after test product intake |
| Performance mirror tracing | Task performance on mirror tracing task | Between 30-45 minutes after test product intake |
| Systolic blood pressure, free living phase | Ambulatory systolic blood pressure during free living phase | Between 80-270 minutes after test product intake |
| Diastolic blood pressure, free living phase | Ambulatory diastolic blood pressure during free living phase | Between 80-270 minutes after test product intake |
| Cortisol, free living phase | Concentration of cortisol in saliva during free living phase | 140, 200 and 260 minutes after test product intake |
| STAI, free living phase | Self-reported mental state: State-Trait Anxiety Inventory during free living phase | 140, 200 and 260 minutes after test product intake |
| UWIST, free living phase | Self-reported mental state: University Of Wales Institute of Science and Technology) mood adjective questionnaire during free living phase | 140, 200 and 260 minutes after test product intake |
| Pulse pressure during stress | Mean pulse pressure during mental stress | Between 30-45 minutes after test product intake |
| Pulse pressure after stress | Mean pulse pressure after acute mental stress | Between 45-60 minutes after test product intake |
| Mental wellbeing | Mental well being as assessed by on line survey an each evening during the 7 day period the accelerometer is worn. | 7 consecutive days prior to the lab sessions |
| Physical activity | Habitual patterns in physical activity as measured by accelerometer | 7 consecutive days prior to the lab sessions |
| STAI screening | State-Trait Anxiety Inventory (STAI) - Trait version, covariate | Screening |
| CES-D | Center for Epidemiologic Studies Depression scale, covariate | Screening |
| CISS | CISS coping scale, covariate | Screening |
| loneliness | UCLA loneliness scale, covariate | Screening |
| Perceived stress | Perceived Stress Scale, covariate | Screening |
| D011687 |
| Purines |
| D006574 | Heterocyclic Compounds, 2-Ring |
| D000072471 | Heterocyclic Compounds, Fused-Ring |