Hot or Cold Beverages in Warm Weather

Study Overview
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Brief Summary
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Some studies have suggested that hot beverages are better for cooling down when body temperature rises. No study has investigated the effect of hot beverages in hot weather on personal well-being compared to cold beverages.

Detailed Description
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The research project will be conducted as a double-blinded randomized crossover trial, where the participants will drink either 10 cl of 10°C cold tea (±2°C) or 50°C hot tea (±2°C), which in a pilot study and in the literature [1,9] has been shown to be without discomfort or side effects. The order of the two interventions will be randomized. All participants must be adults (18 years or older) and not have a fever on the day of the experiment. Prior to participation, participants must provide written informed consent and must show up in clothing they find comfortable in the sun and be wearing sunscreen and a sun hat/cap. Participants must also complete a questionnaire on basic background information: gender, age, height, weight, clothing during the trial, and the participant's preference regarding the climate and temperature of beverages. Walk-through of study: Participants lie or sit in the sun for 10 minutes without drinking anything. Then, participants drink their allocated beverage in ≤ 5 sec. while still in the sun. Approximately 3 minutes (±1 min.) after ingestion of the beverage intervention, participants must answer all questionnaires and have their temperature measured. Afterward, participants stay in the shade for 5 minutes (wash-out period). Participants lie down (or sit) in the sun for the second time for 10 minutes without drinking anything. Then, participants drink their second allocated beverage in ≤ 5 sec. while still in the sun. Approximately 3 minutes (±1 min.) after ingestion of the second beverage intervention, participants must again answer all questionnaires and have their temperature measured. Data collection and the research project end thereafter

Official Title
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Hot or Cold Beverages in Warm Weather: A Double-blinded Randomized Controlled Trial.

Conditions
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Quality of Life

Intervention / Treatment
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* Dietary Supplement: Tea


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18 years or older Must be able to ingest intervention Must be able to be in the sun for 2x 13 minutes (using sunscreen and/or other relevant UV protection). Exclusion Criteria: Fever on the day of the experiment.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Warm tea<br>50 degrees celsius hot tea. | Dietary Supplement: Tea<br>* Orally administered. Decaffeinated tea, with no additives (sugar, honey, etc.)<br>|
| Active Comparator: Cool tea<br>10 degrees celsius cool tea | Dietary Supplement: Tea<br>* Orally administered. Decaffeinated tea, with no additives (sugar, honey, etc.)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thermal well-being | Using the Bedford thermal comfort scale and ASHRAE thermal sensation scale (-3 to 3, higher is hotter) | At 3 minutes after intervention | 
| Mood | Using the Brief Mood Introspection Scale (-24 to 24, higher is more positive) | At 3 minutes after intervention | 
| Pain, discomfort, depression. | Using the 5th domain of the EQ-5D-5L (1-5, higher is more pain and/or discomfort, and more depressed) | At 3 minutes after intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Temperature | Using a forehead thermometer in degrees celsius | At 3 minutes after intervention |