Acute Health Effects of Low 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 low 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 50 healthy young adults in Shanghai, China. Each subject will be exposed twice: once to the low temperature (16#) and once to the moderate temperature (22#) in a chamber for about 2-2.5 hours. During the exposure session, each subject will be requested to rest. Health examinations will be conducted immediately prior to exposure (within 1 hour before the exposure session), during the period of exposure, and after exposure (within 2 hours after the exposure session). Health examinations include spirometry, Holter monitoring, blood pressure tests, cognitive function tests, symptom questionnaires, and magnetic resonance imaging. Investigators plan to collect blood, urine, exhaled breath condensate, and oropharyngeal swabs samples.

Official Title
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Acute Health Effects of Low 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: Low temperature (16#) 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 the 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 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: Low temperature (16#) group<br>Subjects in exposure group will be exposed to low temperature (16#) for about 2 hours in a chamber. | Other: Low temperature (16#) group<br>* The exposure group will be exposed to low temperature (16#) 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 | Investigators plan to measure heart rate variability (HRV) parameters (e.g., SDNN, PNN50, LF, HF) | 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. | 
| 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 | 
| Forced vital capacity | Investigators plan to measure forced vital capacity (FVC) by spirometry | Lung function will be examined before exposure and half an hour after the exposure session | 
| Forced expiratory volume in one second | Investigators plan to measure forced expiratory volume in one second (FEV1) by spirometry. | Lung function will be examined before exposure and half an hour after the exposure session | 
| Maximal mid-expiratory flow | Investigators plan to measure maximal mid-expiratory flow (MMEF) by spirometry. | Lung function will be examined before exposure and half an hour after the exposure session | 
| 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 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes of skin temperature | The changes of wrist skin temperature will be measured | Skin temperature will be examined from 1:00 P.M. to 4:30 P.M. at the day of intervention | 
| Results of simple reaction time | Investigators plan to measure the changes of cognitive function using visual simple reaction time test. | Simple reaction time will be examined before exposure and immediately after the exposure session | 
| Results of visual memory | Investigators plan to measure the changes of cognitive function using visual memory test. Every level, a number of tiles will flash white. The participants will be required to memorize them, and pick them again after the tiles are reset. Higher levels refer to better visual memory. | Visual memory will be examined before exposure and immediately after the exposure session | 
| Activated brain regions demonstrating brain activity related to the low temperature exposure | Investigators plan to conduct magnetic resonance imaging (MRI) after exposure. The MRI data will be processed through Data Processing and Analysis for Brain Imaging (DPABI) sofrware to obtain brain activity parameters, such as fractional amplitude of low-frequency fluctuation (fALFF). Brain regions that change after exposure between the two groups would be further idenfitied. | MRI will be examined 1 hour after the exposure session | 
| Changes in cerebral hemodynamics demonstrating brain activity related to the low temperature exposure | Investigators plan to conduct functional near-infrared spectroscopy (fNIRS) to measure the changes in oxygenated hemoglobin and deoxygenated hemoglobin after exposure. Matlab would be applied to process data and evaluate the changes in cerebral hemodynamics associated with low temperature exposure | fNIRS 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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Low temperature, Randomized controlled trial, Cardiopulmonary effects, Cognitive function