The Effect of Tea Breaks on Cerebrovascular Perfusion During Desk Work

Sedentary behaviour of healthy subjects may have a detrimental impact on cerebral blood flow as well as cognitive measures related to mood and alertness. In this study we focus on the impact of leaving the desk to consume a cup of tea at regular intervals during a sedentary working day.

Study Overview

• Status: Completed
• Conditions: Cerebrovascular Circulation; Affect
• Intervention / Treatment: Other: Tea; Other: Water

Detailed Description

Prolonged desk work has detrimental impact on cerebral blood flow as well as cognitive measures related to mood and alertness caused. These effects might be prevented by taking short breaks with physical activity. Usually, desk workers have short breaks during office times for either a visit to the restroom or to enjoy for a moment a (hot) drink. Consumption of tea has been associated with benefits related to attention, alertness, mood and creativity. This study focuses on the impact of physically leaving the desk to prepare and consume a cup of tea at regular intervals during a sedentary working day.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Liverpool, United Kingdom
    • John Moores University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Healthy males and females, age at screening > 18 and < 60 years;
• BMI > 18 and < 30 kg/m2
• Apparently healthy
• Agreeing to be informed about medically relevant personal test-results by a physician
• Informed consent signed
• Sedentary working individuals (≥6 hours desk work per day, ≥4 days per week)

Exclusion Criteria:

• Reported physical exercise ≥4 hours per week
• Taking medication (including food supplements and traditional medicines) which may interfere with study measurements, as judged by the PI
• Reported participation in another nutritional or biomedical trial (involving an intervention of at least 1 week) 3 months before the screening or during the study
• Reported participation in night shift work 2 weeks prior to screening or during the study. Night work is defined as working between midnight and 6.00 a.m.
• Reported consumption of > 14 units (female subjects) and > 21 units (male subjects) alcoholic drinks in a typical week.
• Reported use of any nicotine containing products in the 6 months preceding the study and during the study itself.
• If female, is pregnant (or has been pregnant during the last < 3 months ago) or will be planning pregnancy during the study period.
• If female, is lactating or has been lactating in the 6 weeks before screening and/or during the study period.
• Reported weight loss/gain (> 10%) in the last 6 months before the study.
• Being an employee of Unilever or an employee or a student working in RISES LJMU that is directly involved in this study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Tea-water; Tea before water	Other: Tea; Subjects walk to a nearby area and prepare a cup of 150 ml tea once every hour. The tea is consumed whilst being seated at their desks.; Other: Water; 150 ml water is served to subjects once every hour. The water is consumed whilst being seated at their desks.
Experimental: Water-tea; Water before tea	Other: Tea; Subjects walk to a nearby area and prepare a cup of 150 ml tea once every hour. The tea is consumed whilst being seated at their desks.; Other: Water; 150 ml water is served to subjects once every hour. The water is consumed whilst being seated at their desks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in cerebrovascular perfusion of tea versus water	Cerebrovascular perfusion measured as middle cerebral artery velocity	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in cerebrovascular auto-regulation gain of tea versus water	Dynamic cerebrovascular autoregulation is assessed via squat-stand manoeuvres performed to elicit oscillations in blood pressure within the high-pass filter frequency range (<0.20 Hz) of the cerebrovascular. Squat-stand cycles are performed at 0.2 Hz (2.5-seconds squatting, followed by 2.5-seconds standing) and at 0.1 Hz (5-seconds squatting, followed by 5-seconds standing) for 5-minutes each, separated by a 5-minute rest. Transfer function analysis is conducted on the beat-to-beat blood pressure and middle cerebral artery blood flow velocity mean signals to produce values of gain (damping effect of Cerebrovascular autoregulation on the magnitude of blood pressure oscillations).	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.
Difference in cerebrovascular auto-regulation phase of tea versus water	Dynamic cerebrovascular autoregulation is assessed via squat-stand manoeuvres performed to elicit oscillations in blood pressure within the high-pass filter frequency range (<0.20 Hz) of the cerebrovascular. Squat-stand cycles are performed at 0.2 Hz (2.5-seconds squatting, followed by 2.5-seconds standing) and at 0.1 Hz (5-seconds squatting, followed by 5-seconds standing) for 5-minutes each, separated by a 5-minute rest. Transfer function analysis is conducted on the beat-to-beat blood pressure and middle cerebral artery blood flow velocity mean signals to produce values of phase (temporal relationship between changes in blood pressure and middle cerebral artery blood flow velocity).	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.
Difference in cerebrovascular auto-regulation coherence of tea versus water	Dynamic cerebrovascular auto-regulation is assessed via squat-stand manoeuvres performed to elicit oscillations in blood pressure within the high-pass filter frequency range (<0.20 Hz) of the cerebrovascular. Squat-stand cycles are performed at 0.2 Hz (2.5-seconds squatting, followed by 2.5-seconds standing) and at 0.1 Hz (5-seconds squatting, followed by 5-seconds standing) for 5-minutes each, separated by a 5-minute rest. Transfer function analysis is conducted on the beat-to-beat blood pressure and middle cerebral artery blood flow velocity mean signals to produce values of coherence (linearity of the relationship between the changes in middle cerebral artery blood flow velocity and blood pressure).	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in PANAS of tea versus water	Positive and Negative Affect Schedule (PANAS) questionnaire consisting of a list of ten positive and ten negative feelings and emotions. Participants rate the extent to which they are feeling each emotion, on a scale from 1 (very slightly or not at all) to 5 (extremely).	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.
Difference in Bond-Lader of tea versus water	Bond-Lader questionnaire: 16 adjective pairs with a 100mm line in between. Three sub-scales will be calculated: Alertness, Contentedness and Calmness.	Immediately before and immediately after each of the two 6-hour interventions. The 'before' results will be added to the mixed model as a covariate.
Difference in affect of tea versus water	Affect grid. Two dimensional grid of 19x19 cells scoring pleasure and arousal	Before (0) and at 1, 2, 3, 4 and 5 hours during tea and water interventions. Both dimensions will be tested in a repeated measures linear mixed model. The treatment effect is the difference in the least square means of tea versus water.

Collaborators and Investigators

• Sponsor: Unilever R&D
• Collaborators: Liverpool John Moores University
• Investigators: Principal Investigator: Dick Thijssen, prof, Liverpool John Moores University

Study record dates

Study Major Dates

• Study Start (Actual): April 30, 2019
• Primary Completion (Actual): June 24, 2019
• Study Completion (Actual): July 15, 2019

Study Registration Dates

• First Submitted: April 24, 2019
• First Submitted That Met QC Criteria: May 14, 2019
• First Posted (Actual): May 16, 2019

Study Record Updates

• Last Update Posted (Actual): August 7, 2019
• Last Update Submitted That Met QC Criteria: August 6, 2019
• Last Verified: August 1, 2019

More Information

Terms related to this study

• Other Study ID Numbers: REF-BEV-3235

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No