The Association Between Core Temperature and Health

Volunteers will swallow an electronic capsule called e-Celsius (BodyCap, France) which will be activated before use. Four hours after swallowing, the e-Celsius will enter intestine and data collection will start. A device call e-Viewer (KIT EPERF CE-SW, France) will be used to connect the capsules and collect data.

Volunteers will be asked to fast overnight and weight will be measured using a calibrated Seca body weight scale first thing in the morning on subjects wearing light clothes and no shoes.

Measured by Seca 217 Stable Stadiometer. Volunteers should not wear shoes and socks. Stand on the stadiometer platform with back against the wall and feet together. Stand up as straight as possible with heels, back, shoulders, and head all touching the wall. Tuck in chin and look straight ahead.

BMI will be calculated based on weight and height according to the formula: BMI=Weight/Height^2

Fat mass will be measured by Magnetic Resonance Imaging (Shanghai united imaging, uMR 790 ). Volunteers should wear no metal jewelries or with metal implants. They should lie down on a movable table and be fasten by technologists. Volunteers should hold still during the test and perform a few small tasks, such as exhale, inhale, and hold breath following the broadcast.

Fat free mass will be measured by Bioimpedance Analysis (Tanita, MC-980). Demographic information of volunteers should be entered before test, including ID number, sex, age, height. When the signal showing the machine is ready, volunteers should stand on the scale without shoes, socks or any pieces which might influence weight. According to the instruction of display screen, volunteers need to hold the handle tightly.

Fat free mass will be measured by DEXA (Horizon Wi). Volunteers will be asked to lie on a special DEXA x-ray table. The technologist will help position your correctly and use positioning devices such as foam blocks to help hold the desired position. As the arm of the DEXA machine passes over the body, IT uses two different x-ray beams. The beams use very little radiation to keep the test safer, and help to distinguish bone from other tissues. The scanner translates the bone density measurement data into pictures and graphs. Bone is most easily seen in white, while the, fat and muscle tissue look like shadows in the background on the technologist's computer monitor.

Waist circumferences will be measured using a whole body laser scanner (TG2000-F). Volunteers should wear tight underwear during test and stand in front of the machine according to the stickers of instruction. Do some small movement according to instruction.

Hip circumferences will be measured using a whole body laser scanner (TG2000-F). Volunteers should wear tight underwear during test and stand in front of the machine according to the stickers of instruction. Do some small movement according to instruction.

The infrared thermal imager (Fluke RSE600) will be used to measure brown adipose tissue around clavicle. Each subject was in a relaxed "steady-state" within a familiar environment. They were seated in an upright posture, with arms adducted and with head, neck, and shoulders unclothed, in the center of the study room, away from all heat-emitting objects and 1.0 m away from a thermal imaging camera fixed on a tripod at a set distance, 1 m, from the floor. This positioning ensured comfort as well as the optimum position for visualization of the supraclavicular BAT depots. 5 images were taken at 1-minute intervals before each thermal challenge and represented the control period. Each subject then placed 1hand into cool tap water (20℃).The increase in temperature in the thermal area in the supraclavicular region was further collected.

Physical activity of the volunteers will be recorded using accelerometer (GT3X) worn near the hip for a consecutive period of 7 days. The monitor should not be worn while bathing or swimming. The first day is discarded along with any day where the wear time is less than 12 hours. For a valid measure the goal is to get 2 weekday and 2 weekend days. The acceleration of three axises will be collected and then calculated into the intensity of physical activity.

Food intake was monitored using the 24-hour Dietary Review questionnaire (a retrospective record of food intake (quantity and frequency) over the past 24 hours using a self-reported questionnaire).

Resting energy expenditure will be measured using indirect calorimetry via a respiratory hood system (Cosmed). The volunteer attends in the lab after an overnight fast. The person lies down on a flat bed and the hood is placed over their head. Metabolic rate (oxygen consumption and CO2 production) are monitored for 40 minutes. The last 10 minutes is used as the measurement. Calorimeters will be assessed with a turbine test to ensure accuracy of measurements. Validation via an alcohol burn will be performed monthly.

Venous blood sample will be collected by professional nurse for glucose test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for IL-6 test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for TNF-Alpha test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for HDL test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for LDL test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for TG test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse for insulin test in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital.

Venous blood sample will be collected by professional nurse in the morning after 12 hour fasting and be examined by Shenzhen University General Hospital. Index of albumin, creatinine, glucose, c-creative protein, lymphocyte percentage, mean corpuscular volume, red cell distribution width, alkaline phosphatase, white blood cell count will be examined and calculated into Phenotypic Age.

Bone mass will be measured by DEXA (Horizon Wi). Volunteers will be asked to lie on a special DEXA x-ray table. The technologist will help position your correctly and use positioning devices such as foam blocks to help hold the desired position. As the arm of the DEXA machine passes over the body, IT uses two different x-ray beams. The beams use very little radiation to keep the test safer, and help to distinguish bone from other tissues. The scanner translates the bone density measurement data into pictures and graphs. Bone is most easily seen in white, while the, fat and muscle tissue look like shadows in the background on the technologist's computer monitor.

Volunteers will go to the Health Management Center of Shenzhen University General Hospital, where professional doctors will use a photocoherence tomography scanner (Spectralis OCT) for fundus examination, and fundus imaging will be collected without invasiveness and harm. Volunteers need to sit comfortably in a chair and move their face close to the camera device. Technologist will show where to place forehead and chin. Nothing touches volunteers' eye during retinal imaging.

Facial features are captured using an infrared thermal imager (Fluke RSE600), which are then analyzed using artificial intelligence. When shooting, wait for the thermal imager to focus and press the shutter. During image acquisition, the frame should contain only one subject, whose face and head information are fully collected, and the area above the neck accounts for more than 35% of the thermal image captured. During the collection process, volunteers are reminded to look up at the camera, not to make expressions, not to wear glasses that cover their faces, masks, etc. In the event that the volunteer has bangs or long hair covering their face, the volunteer should be reminded to put on a headband and tie their hair back.

Muscle strength will be measure by Jamar Plus+ Digital Hand Dynamometer. Volunteers will comfortably arrange the instrument in his/her hand. Have volunteers squeeze with their maximum strength. The peak-hold needle will automatically record the highest force exerted.

Abundance of gut microbiome will be from Metagenomic profiling of feces by Illumina. Volunteers will collect their feces by themselves using a specialized feces collection tubes. They need to submit the samples to the researcher within 30 minutes after collection or they need to first store in the freezer and then submit the sample when available.

The researcher will take a drop of blood from the volunteers' finger stick, use the kit to store the fingerstick blood, and then send it to the company for testing. Biological age score based on glycan biomarkers that indicate inflammation will be available in 3-5 weeks.