Heat Stress
Conditions
Keywords
Heat Strain, Wearable, Sweat Analysis
Brief summary
• This study investigates and compares the within and in-between variances of the body responses to different heat stressors in a controlled lab-setting. The participants will be exposed to different heat sources while a variety of physiological heat strain reactions such as heartrate, sweat rate, and core body temperature are recorded using on- and in-body devices. For the participant monitoring during the study, medical grade devices such as a certified ECG and a swallowable sensor-pill to continuously monitor the core body temperature will be applied. A one-for-all wearable device is additionally applied for physiological validation. Further, sweat will be collected to assess (i) the local sweat rate and (ii) the appearance of different heat stress associated molecular markers in this non-invasively collectable biofluid. As a secondary aim, a model will be developed that will enable to predict the different heat stress sources out of the heat strain measurements.
Interventions
OTHERElevated ambient heat
Temporary exposure to increased ambient temperature +10°C (the effect of the intervention is fully and spontaneously reversible)
OTHERElevated relative humidity
Temporary exposure to increased ambient relative humidity +40% (max. 90%) (the effect of the intervention is fully and spontaneously reversible)
OTHERExertion
Temporary exertion on an ergometer (1W/kg body weight) (the effect of the intervention is fully and spontaneously reversible)
Sponsors
Swiss Federal Office of Sports (BASPO)
University of Zurich
Center for Chronobiology, Psychiatric University Clinics, Basel
epyMetrics
Innosuisse - Swiss Innovation Agency
Swiss Federal Railways
ETH Zurich
Study design
Observational model
OTHER
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy participant, able to give consent * Age 18-40 years * Non-athlete (\<4h sport/week) * BMI\<30 (non-obese) * German speaking, or fluent in German
Exclusion criteria
* Pregnancy (urine pregnancy test), and breastfeeding * Regular medication intake (excluding birth control pill) * Intake of drugs and/or daily alcohol consumption * Fever or symptoms of an acute infection (cough, shortness of breath, sore throat, taste loss) * Active smoking or history of smoking \<9 months ago * Mobility impairment * Traveled (\<1 month ago) to a warm/hot temperature zone and stayed for \>6 days * Any chronic conditions such as: high blood pressure, diabetes mellitus, immuno-deficiencies, sweat disorders such as anhidrosis * Color blindness (STROOP test) * Weight \<40 kg (e-Celsius pill) * Diverticulum or obstructions of the gastrointestinal tract (including motility disorders, swallowing disorders) as well as major abdominal surgery (e-Celsius pill) * Need of exposure to strong electromagnetic fields during study participation, above all MRI examinations (e-Celsius pill)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The within and between subject heat strain marker variability in relation to specific heat stress sources (ambient heat, ambient humidity, exertion, and clothing) | Max. 7 days | The primary endpoint is the within- and between- subject heat strain marker variability of HR, CBT, WSR, and LSR in relation to various heat stress sources (increased ambient temperature, increased relative humidity, and exertion, all without and with additional clothing. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Accuracy to detect the specific heat stress source (such as ambient heat, relative humidity) from different on- and in-body measurements | Max. 7 days | The models for the primary endpoints will be extended to explore the relationships between heat strain parameters, heat stress sources, as well as personal characteristics. Additionally, prediction of heat stress source will be explored. |
| Assessment of short-term heart rate variability in context to each heat stressor. | Max. 7 days | Short-term HRV with a repeating time frame of 5min. Root mean square of successive RR interval (RMSSD; in \[ms\]) and the Standard-deviation of RR intervals (SDRR; in \[ms\]) will be computed with respect to each heat stress source. |
| Temperature [°C] and relative humidity [%] of the microenvironment as an additional source of information for patterns to detect heat stressors | Max. 7 days | Features of temperature \[°C\] and relative humidity \[%\] of the microenvironment as additional model predictors. |
Other
| Measure | Time frame | Description |
|---|---|---|
| The relation between cognitive assessment and skin temperature | Max. 7 days | Correlation between subjective heat comfort (Visual Analog Scale, where +1 is comfortable and +4 is very uncomfortable) and baseline differential stress inventory (causes of stress, symptoms of stress, coping, stress stabilization) in relation to skin temperature \[°C\] |
| The relation between STROOP assessment and different heat stressors | Max. 7 days | Correlation between changes in the STROOP assessment outcome (number of errors and time of decision \[ms\], between beginning and end of heat stress exposure) in context to the various heat stress sources, skin temperature, and thermal comfort. |
| Novel Sweat Biomarkers for heat stress detection | Max. 7 days | Descriptive statistics for novel non-invasive biomarkers from sweat analysis with respect to heat stress source, including between- and within-subject variability |
| Recording heat strain parameters with an all-for-one device | Max. 7 days | The 'reliability' (missing data per minute (\[%\]) and the 'accuracy' (HR \[bpm\] with 95% confidence intervals), CBT (in \[°C\] with 95% confidence intervals), and local sweat rate measurements (in \[g/h\] with 95% confidence intervals) of the wearable device in recording vital parameters. |
Countries
Switzerland
Outcome results
None listed