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Completed

NCT Number: NCT05622188

The Detection of Heat Stress by Assessing Individual Body Responses to Heat (Heat Strain) in Young and Healthy Non-athlete Participants

• 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.

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Key information

Conditions

Heat Stress Heat Stress Disorders Wounds and Injuries

Age range

18 year–40 year

Sex eligibility

All sexes

Study type

Observational

Primary location

ETH Zurich

Zurich, Andere (Nicht USA-Länder), 8093, Switzerland

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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)

Treatment and study plan

Elevated ambient heat

Other

Temporary exposure to increased ambient temperature +10°C (the effect of the intervention is fully and spontaneously reversible)

Elevated relative humidity

Other

Temporary exposure to increased ambient relative humidity +40% (max. 90%) (the effect of the intervention is fully and spontaneously reversible)

ExeRTiOn

Other

Temporary exertion on an ergometer (1W/kg body weight) (the effect of the intervention is fully and spontaneously reversible)

Primary outcomes

  1. The within and between subject heat strain marker variability in relation to specific heat stress sources (ambient heat, ambient humidity, exertion, and clothing)

    Time frame: 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 outcomes

  1. Accuracy to detect the specific heat stress source (such as ambient heat, relative humidity) from different on- and in-body measurements

    Time frame: 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.

  2. Assessment of short-term heart rate variability in context to each heat stressor.

    Time frame: 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.

  3. Temperature [°C] and relative humidity [%] of the microenvironment as an additional source of information for patterns to detect heat stressors

    Time frame: Max. 7 days

    Features of temperature [°C] and relative humidity [%] of the microenvironment as additional model predictors.

Other outcomes

  1. The relation between cognitive assessment and skin temperature

    Time frame: 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]

  2. The relation between STROOP assessment and different heat stressors

    Time frame: 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.

  3. Novel Sweat Biomarkers for heat stress detection

    Time frame: 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

  4. Recording heat strain parameters with an all-for-one device

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

ETH Zurich

Other

Collaborators

  • Center for Chronobiology, Psychiatric University Clinics, Basel
  • Innosuisse - Swiss Innovation Agency
  • Swiss Federal Office of Sports (BASPO)
  • Swiss Federal Railways
  • University of Zurich
  • epyMetrics

Registry information

Official study title

HEAT Stress Detection From Personally STandARdized Heat Strain Measurements - The HEATSTAR Pilot Trial

Acronym: HEATSTAR

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Nov 18, 2022
Registry last updated
Feb 13, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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