Acute Health Effects of High Temperature Exposure

Study Overview
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Brief Summary
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This is a randomized controlled human exposure crossover study. Investigators aims to assess the acute effects of high temperature exposure and the underlying mechanisms.

Detailed Description
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The investigators will conduct a randomized controlled human exposure crossover study among about 40 healthy young adults in Shanghai, China. Each subject will be exposed twice: once to the high temperature (32℃) and once to moderate temperature (22℃) in a chamber for about 2 hours. During the exposure session, each subject will be requested to rest. Health examinations will be conducted immediately prior to exposure, during the period of exposure and after exposure. Health examinations include symptom questionnaire, blood pressure tests, cognitive function tests, magnetic resonance imaging, skin tests, spirometry, and Holter monitoring. Investigators plan to collect blood, urine and oropharyngeal swabs samples.

Official Title
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Acute Health Effects of High Temperature Exposure in Healthy Young Adults: a Randomized Controlled Study

Conditions
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Cardiovascular System, Respiratory System, Cognitive Function

Intervention / Treatment
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* Other: high temperature (32℃) group
* Other: moderate temperature (22℃) group


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Living in Shanghai during the study period; Body mass index > 18.5 and ≤ 28; right-handed; receiving or having received higher education; with ability to read and understand Chinese smoothly. Exclusion Criteria: Smoking and alcohol abuse; Current drug and dietary supplements intake; Subjects with allergic diseases, such as allergic rhinitis, allergic asthma, and atopy; Subjects with cardiovascular diseases, such as congenital heart disease, pulmonary heart disease, and hypertension; Subjects with respiratory diseases, such as asthma, chronic bronchitis, and chronic obstructive pulmonary disease; Subjects with chronic diseases, such as diabetes, chronic hepatitis, and kidney disease; Subjects who have a history of major surgery due to the cardiovascular, cerebrovascular, respiratory, or neurological diseases; Subjects with neurologic disorders, such as stroke, traumatic brain injury, epilepsy, and schizophrenia; Abnormal spirometry (FEV1 and FVC ≤ 75% of predicted and FEV1/FVC ≤ 0.65); Subjects with color vision disabilities.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: high temperature (32℃) group<br>Subjects in exposure group will be exposed to high temperature (32℃) for about 2 hours in a chamber. | Other: high temperature (32℃) group<br>* The exposure group will be exposed to high temperature (32℃) in a chamber for about 2 hours, resting during the whole periods.<br>|
| Sham Comparator: moderate temperature (22℃) group<br>Subjects in exposure group will be exposed to moderate temperature (22℃) for about 2 hours in a chamber. | Other: moderate temperature (22℃) group<br>* The exposure group will be exposed to thermoneutral temperature (22℃) in a chamber for about 2 hours, resting during the whole periods.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart Rate Variability Parameters SDNN | Investigators plan to measure standard deviation of NN intervals (SDNN) in millisecond. | Volunteers will be asked to wear electrographic Holter monitors for 24 hours from 1:00 P.M. at the day of intervention to 1:00 P.M. at the next day. | 
| Results of Stroop Tests | Investigators plan to measure the changes of cognitive function using Stroop Test. | The tests will be conducted before exposure and immediately after the exposure session | 
| Results of schulte table Tests | Investigators plan to measure the changes of cognitive function using schulte table. | The tests will be conducted before exposure and immediately after the exposure session | 
| Activated brain regions demonstrating brain activity related to the high temperature exposure | Investigators plan to measure brain activity associated with high temperature exposure by magnetic resonance imaging (MRI). Brain imaging data will be extracted from MRI data. | 1 hour after exposure session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of lung function indicators forced vital capacity (FVC) | Investigators plan to measure the changes of forced vital capacity. | FVC will be examined before exposure and half an hour after exposure | 
| Changes of lung function indicators forced expiratory volume in 1 second (FEV1) | Investigators plan to measure the changes of forced expiratory volume in 1 second. | FEV1 will be examined before exposure and half an hour after exposure | 
| Changes of the scores of cardiovascular symptoms questionnaires | Changes of scores of cardiovascular symptoms questionnaires which ranged from 0 to 40. Higher scores of the cardiovascular symptoms questionnaires mean more severe cardiovascular symptoms. | The cardiovascular symptoms questionnaires will be conducted before exposure and immediately after the exposure session | 
| Blood Pressure | The changes of systolic blood pressure (SBP) and diastolic blood pressure (DBP) will be measured. | Blood pressure will be examined before exposure and immediately after the exposure session | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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High Temperature, Randomized controlled trial, Cardiovascular effects, cognitive function