Acute Effects of Low Temperature Exposure on Respiratory System

N/AActive Not RecruitingNCT06652932

Fudan University40 enrolled

Overview

This is a randomized controlled human exposure crossover study. Investigators aims to assess the acute effects of low-temperature exposure on respiratory health and the underlying mechanisms.

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 low temperature (15℃) and once to the 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 lung function tests and exhaled breath test. Investigators plan to collect blood, pharyngeal secretion, exhaled breath condensate and urine samples.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Enrollment

Conditions

Lung Function

Interventions

Low temperature (15°C) groupOTHER

The exposure group will be exposed to low temperature (15°C) in a chamber for about 2 hours, resting during the whole periods.

Moderate temperature (22°C) groupOTHER

The exposure group will be exposed to thermoneutral temperature (22°C) in a chamber for about 2 hours, resting during the whole periods.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 30 YearsHealthy volunteers:

Medical Language ↔ Plain English

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 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.

Locations (1)

Department of Environmental Health, School of Public Health, Fudan University

Shanghai, Shanghai Municipality, China

Outcomes

Primary Outcomes

Changes of forced expiratory volume in the first second (FEV1)

Investigators plan to measure the changes of the forced expiratory volume in 1 s (FEV1) using a smart spirometer (Model A1, BreathHome, China) supervised by professional medical staff. Before the pulmonary function test, subjects will practice several times by themselves. During the examination, each subject stands and clamps the nose clip, and repeats the test, with the best result as the criterion. FEV1 reflect pulmonary function.

Time frame: The tests will be conducted at 12:30 A.M. (half an hour before exposure) and 3:30 P.M. (half an hour after the exposure)

Changes of forced vital capacity (FVC)

Investigators plan to measure the changes of forced vital capacity (FVC) using a portable spirometer (Jaeger Master screen V5.01; CareFusion). FVC reflects the expiratory resistance of large airways.

Time frame: FVC will be examined at 12:30 A.M. (half an hour before exposure) and 3:30 P.M. (half an hour after the exposure)

Changes of peak expiratory flow rate (PEF)

Investigators plan to measure the changes of peak expiratory flow (PEF) using a portable spirometer (Jaeger Master screen V5.01; CareFusion). PEF reflects airway patency and respiratory muscle strength.

Time frame: FVC will be examined at 12:30 A.M. (half an hour before exposure) and 3:30 P.M. (half an hour after the exposure)

Changes of maximum expiratory flow rate at 25% vital capacity (MEF25)

Investigators plan to measure the changes of maximum expiratory flow rate at 25% vital capacity. MEF25% reflects the early stage of expiratory flow rate.

Time frame: MEF25 will be examined at 12:30 A.M. (half an hour before exposure) and 3:30 P.M. (half an hour after the exposure)

Changes of maximum expiratory flow rate at 50% vital capacity (MEF50)

Investigators plan to measure the changes of maximum expiratory flow rate at 50% vital capacity using a portable spirometer (Jaeger Master screen V5.01; CareFusion). MEF50 reflects the interim stage of expiratory flow rate.

Data from ClinicalTrials.gov

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Secondary Outcomes

Changes of fractional exhaled nitric oxide (FeNO)

Investigators plan to measure the changes of fractional exhaled nitric oxide using FeNO monitor (NIOX; Aerocrine AB, Solna, Sweden). FeNO reflects airway inflammation level

Time frame: FeNO will be examined half an hour before exposure and half an hour after exposure

Changes of fractional concentration of carbon monoxide (FeCO)

Investigators plan to measure the changes of fractional concentration of carbon monoxide using Pico Smokerlyzer. FeCO reflects level of carboxyhemoglobin in blood.

Time frame: FeCO will be examined at 12:30 A.M. (half an hour before exposure) and 3:30 P.M. (half an hour after the exposure)

Changes of skin temperature

The changes of wrist skin temperature will be measured

Time frame: Wrist skin temperature will be measured at 1:00 P.M. to 3:00 P.M. on the day of the exposure session