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Completed

NCT Number: NCT03953391

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.

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Key information

Conditions

Cerebrovascular Circulation Affect

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

John Moores University

Liverpool, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Tea

Other

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.

Water

Other

150 ml water is served to subjects once every hour. The water is consumed whilst being seated at their desks.

Primary outcomes

  1. Difference in cerebrovascular perfusion of tea versus water

    Time frame: 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.

    Cerebrovascular perfusion measured as middle cerebral artery velocity

Secondary outcomes

  1. Difference in cerebrovascular auto-regulation gain of tea versus water

    Time frame: 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.

    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).

  2. Difference in cerebrovascular auto-regulation phase of tea versus water

    Time frame: 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.

    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).

  3. Difference in cerebrovascular auto-regulation coherence of tea versus water

    Time frame: 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.

    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).

Other outcomes

  1. Difference in PANAS of tea versus water

    Time frame: 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.

    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).

  2. Difference in Bond-Lader of tea versus water

    Time frame: 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.

    Bond-Lader questionnaire: 16 adjective pairs with a 100mm line in between. Three sub-scales will be calculated: Alertness, Contentedness and Calmness.

  3. Difference in affect of tea versus water

    Time frame: 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.

    Affect grid. Two dimensional grid of 19x19 cells scoring pleasure and arousal

Sponsors and collaborators

Lead sponsor

Unilever R&D

Industry

Collaborators

  • Liverpool John Moores University

Registry information

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
May 16, 2019
Registry last updated
Aug 7, 2019

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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