This is a randomized controlled human exposure crossover study. Investigators aim to assess the acute effects of low temperature exposure on cardiovascular system 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°C) and once to the moderate temperature (22°C) in a chamber for about 2 hours. During the exposure session, each subject will be requested to rest. Health examinations will be conducted at baseline immediately prior to exposure, during the period of exposure, and after exposure. Health examinations include blood pressure tests and Holter monitoring. Investigators plan to collect blood and urine samples.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
40
The exposure group will be exposed to low temperature (15°C) in a chamber for about 2 hours, resting during the whole periods.
The exposure group will be exposed to thermoneutral temperature (22°C) in a chamber for about 2 hours, resting during the whole periods.
Department of Environmental Health, School of Public Health, Fudan University
Shanghai, Shanghai Municipality, China
RECRUITINGBlood Pressure
The changes of systolic blood pressure (SBP) and diastolic blood pressure (DBP) will be measured.
Time frame: Blood pressure will be examined before exposure and immediately after the exposure session
SDNN (standard deviation of NN intervals)
Investigators plan to measure heart rate variability (HRV) parameter SDNN
Time frame: 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.
SDANN (standard deviation of the averages of RR intervals)
Investigators plan to measure heart rate variability parameter SDANN
Time frame: 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.
rMSSD (root mean square of successive differences)
Investigators plan to measure heart rate variability (HRV) parameter rMSSD
Time frame: 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.
pNN50 (Percentage of differences between adjacent RR intervals greater than 50 ms)
Investigators plan to measure heart rate variability (HRV) parameter pNN50
Time frame: 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.
Frequency domain measures: low frequency (LF), high frequency (HF), and LF/HF ratio
Investigators plan to measure frequency domain parameters of heart rate variability (HRV)
Time frame: 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.
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Changes of scores of symptoms questionnaires
The changes of scores of respiratory and cardiovascular symptoms questionnaires both the total and each symptom specified
Time frame: The questionnaires will be conducted before exposure and immediately after the exposure
Changes of skin temperature
The changes of wrist skin temperature will be measured
Time frame: Skin temperature will be examined during the 2-hour exposure session