Prediction of facial cooling while walking in cold wind

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

Mass Participation and Tournament Event Management for the Team Physician: A Consensus Statement (2022 Update)

ABSTRACT

Mass participation events include endurance events (e.g., marathon, triathlon) and/or competitive tournaments (e.g., baseball, tennis, football (soccer) tournaments). Event management requires medical administrative and participant care planning. Medical management provides safety advice and care at the event that accounts for large numbers of participants, anticipated injury and illness, variable environment, repeated games or matches, and mixed age groups of varying athletic ability. This document does not pertain to the care of the spectator.

ACSM Expert Consensus Statement: Injury Prevention and Exercise Performance during Cold-Weather Exercise

ABSTRACT

Cold injury can result from exercising at low temperatures and can impair exercise performance or cause lifelong debility or death. This consensus statement provides up-to-date information on the pathogenesis, nature, impacts, prevention, and treatment of the most common cold injuries.

Human cold stress of strong local-wind "Hijikawa-arashi" in Japan, based on the UTCI index and thermo-physiological responses

We investigated the cold stress caused by a strong local wind called "Hijikawa-arashi," through in situ vital measurements and the Universal Thermal Climate Index (UTCI). This wind is a very interesting winter phenomenon, localized in an area within 1 km of the seashore in Ozu City, Ehime Prefecture in Japan. When a strong Hijikawa-arashi (HA) occurred at 14-15 m s^-1, the UTCI decreased to - 30 °C along the bridge where commuting residents are the most exposed to strong and cold winds. On the bridge, most participants in our experiment felt "very cold" or "extremely cold." The UTCI of HA can be predicted from a multiple regression equation using wind speed and air temperature. The cold HA wind is also harmful to human thermo-physiological responses. It leads to higher blood pressure and increased heart rate, both of which act as cardiovascular stress triggers. Increases of 6-10 mmHg and 3-6 bpm for every 10 °C reduction in UTCI were seen on all observational days, including HA and non-HA days. In fact, the participants' body skin temperatures decreased by approximately 1.2 to 1.7 °C for every 10 °C reduction in UTCI. Thus, the UTCI variation due to the HA outbreak corresponded well with the cold sensation and thermo-physiological responses in humans. This result suggests that daily UTCI monitoring enables the prediction of thermo-physiological responses to the HA cold stress.

Measuring facial cooling in outdoor windy winter conditions: an exploratory study

Winter clothing provides insulation for almost all of a person's body, but in most situations, a person's face remains uncovered even in cold windy weather. This exploratory study used thermal imagery to record the rate of cooling of the faces of volunteers in a range of winter air temperatures and wind speeds. Different areas of the faces cooled at different rates with the areas around the eyes and neck cooling at the slowest rate, and the nose and cheeks cooling at the fastest rate. In all cases, the faces cooled at an approximately logarithmic decay for the first few minutes. This was followed by a small rise in the temperature of the face for a few minutes, which was then followed by an uninterrupted logarithmic decay. Volunteers were told to indicate when their face was so cold that they wanted to end the test. The total amount of time and the facial temperature at the end of each trial were recorded. The results provide insight into the way faces cool in uncontrolled, outdoor winter conditions.

Notes on the implementation of the IREQ model for the assessment of extreme cold environments

This paper has been devoted to the difficulties that practitioners, skilled ergonomists or occupational health experts could find in the assessment of cold environments by means of (insulation required) IREQ model at the base of the (International Standardization Organization) ISO 11079 Standard. The in-depth analysis discussed here has underlined several difficulties about: (a) the graphical calculation of the predicted limit exposures; (b) some differences in both IREQ and (duration limit exposure) DLE values reported in ISO 11079; and (c) some errors and incongruities in the program available online for the assessment of DLEs. These occurrences lead to the systematic overestimation of the DLE that exceed up to 4 h, those obtained by means of the figures reported in the Standard with the consequent unreliable assessment. Such matters justify the need to promote, in the whole scientific community involved in the ergonomics of the thermal environment, an in-depth discussion on the best practice to be followed for the assessment of extreme cold environments by means of IREQ model.

PRACTITIONER SUMMARY

Incongruities in IREQ model and errors in the code suggested by ISO 11079 Standard prevent a reliable assessment of cold environments with DLE systematically overestimated. Therefore IREQ model has been theoretically investigated trying to help both neophytes and skilled ergonomists on the best practice to be followed.

Facial convective heat exchange coefficients in cold and windy environments estimated from human experiments

Facial heat exchange convection coefficients were estimated from experimental data in cold and windy ambient conditions applicable to wind chill calculations. Measured facial temperature datasets, that were made available to this study, originated from 3 separate studies involving 18 male and 6 female subjects. Most of these data were for a -10°C ambient environment and wind speeds in the range of 0.2 to 6 m s(-1). Additional single experiments were for -5°C, 0°C and 10°C environments and wind speeds in the same range. Convection coefficients were estimated for all these conditions by means of a numerical facial heat exchange model, applying properties of biological tissues and a typical facial diameter of 0.18 m. Estimation was performed by adjusting the guessed convection coefficients in the computed facial temperatures, while comparing them to measured data, to obtain a satisfactory fit (r(2) > 0.98, in most cases). In one of the studies, heat flux meters were additionally used. Convection coefficients derived from these meters closely approached the estimated values for only the male subjects. They differed significantly, by about 50%, when compared to the estimated female subjects' data. Regression analysis was performed for just the -10°C ambient temperature, and the range of experimental wind speeds, due to the limited availability of data for other ambient temperatures. The regressed equation was assumed in the form of the equation underlying the "new" wind chill chart. Regressed convection coefficients, which closely duplicated the measured data, were consistently higher than those calculated by this equation, except for one single case. The estimated and currently used convection coefficients are shown to diverge exponentially from each other, as wind speed increases. This finding casts considerable doubts on the validity of the convection coefficients that are used in the computation of the "new" wind chill chart and their applicability to humans in cold and windy environments.