Heat Acclimation and Thermotolerance, Heat Effect
Conditions
Keywords
Heat Stress, Exposure time, Gender difference, WBGT
Brief summary
Background: Core body temperature increases in hot climates due to exercise workload, disrupting heat gain and loss of balance. The human thermoregulatory system regulates core body temperature through factors such as metabolic heat production, air temperature, humidity, and clothing. The study investigates physiological thermoregulatory responses in semiprofessional athletes during walking and jogging in different climatic conditions. Methods: A factorial experimental interventional design was used to evaluate different physical activity (low (L)=5 km/h and high (H)=8 km/h) and climatic conditions within the Thermal Environment Laboratory at Lund University, Sweden. The temperature within the climatic chamber was set at 40°C and 31°C, with a relative humidity of 20% and 70%, (hot dry (HD) and hot humid (HW), respectively, to account for a 28°C WBGT. The study used independent T-tests, ANOVA and simple linear regression models to analyse the physiological responses of semiprofessional athletes under different test conditions, comparing gender differences.
Interventions
OTHERhot dry high (HDH)
Relative Humidity (%) 39.7±0.3 Vapor Pressure (kPa) 29.0±1.2 Bruel and Kjear (WBGT ºC) 1007.9± 6.4 Heat Stress (WBGT ºC) 28.9±0.6 Air Velocity (m/s) 28.4±0.3
OTHERhot wet high (HWH)
Air Temperature (ºC) 30.6±1.2 Relative Humidity (%) 68.6±1.3 Vapour Pressure (kPa) 1011±1.1 Bruel and Kjear (WBGT ºC) 27.3±0.8 Heat Stress (WBGT ºC) 27.8±0.8 Air Velocity (m/s) 0.45±0.19
OTHERExperimental: hot dry low (HWL)
Relative Humidity (%) 31.1±0.1 Vapor Pressure (kPa )67.1±1.0 Bruel and Kjear (WBGT ºC)1005.7±8.0 Heat Stress (WBGT ºC) 27.4±0.6 Air Velocity (m/s) 27.9±0.3
OTHERExperimental: hot wet low (HWL)
Relative Humidity (%) 39.8±0.1 Vapor Pressure (kPa) 26.4±0.4 Bruel and Kjear (WBGT ºC) 1004.7±10.7 Heat Stress (WBGT ºC) 28.3±0.3 Air Velocity (m/s) 27.7±0.1
Sponsors
University of Valladolid
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
A factorial experimental interventional study design
Eligibility
Sex/Gender
ALL
Age
18 Years to 50 Years
Healthy volunteers
Yes
Inclusion criteria
* Participation at the regional competition level * Receiving monetary remuneration for their sports engagement * Participating in sports activities in the previous six years * Average training experience of 6.0±1.4 years * A weekly volume of 6.3±0.7 days for 2.3±0.7 hours (h)·day-¹.
Exclusion criteria
* A 2 kg weight change in the previous month * Adherence to special diets * Use of nutritional supplements * Smoking * An acute or chronic communicable or noncommunicable disease * Heat allergic problems.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Exposure Time | Just one day, the day of the test, in those weather conditions | duration an athlete is exposed to a specific intensity or environmental condition |
| Heart Rate | Just one day, the day of the test, in those weather conditions | measures how hard your heart works to gauge fitness |
| Oxygen Uptake | Just one day, the day of the test, in those weather conditions | how much oxygen your body uses during activity |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Sweat Rate | Just one day, the day of the test, in those weather conditions | the amount of fluid your body loses through sweat per hour during exercise |
| Core Body Temperature | Just one day, the day of the test, in those weather conditions | the body's internal temperature regulation |
| Thermal Sensation Level | Just one day, the day of the test, in those weather conditions | The Thermal Sensation Level is a standardized, subjective rating system used to quantify a person's perception of warmth or coolness in their environment |
| Perceived Exertion Level | Just one day, the day of the test, in those weather conditions | is a subjective scale that measures how hard your body feels it's working during exercise |
| Skin Temperature | Just one day, the day of the test, in those weather conditions | The temperature of your body's surface |
| Body Temperature | Just one day, the day of the test, in those weather conditions | the internal heat level of the human body |
Countries
Spain
Outcome results
None listed