Validity of inner canthus temperature recorded by infrared thermography as a non-invasive surrogate measure for core temperature at rest, during exercise and recovery

Abstract

Research into obtaining a fast, valid, reliable and non-invasive measure of core temperature is of interest in many disciplinary fields. Occupational and sports medicine research has attempted to determine a non-invasive proxy for core temperature particularly when access to participants is limited and thermal safety is of a concern due to protective encapsulating clothing, hot ambient environments and/or high endogenous heat production during athletic competition. This investigation aimed to determine the validity of inner canthus of the eye temperature (T) as an alternate non-invasive measure of intestinal core temperature (T) during rest, exercise and post-exercise conditions. Twelve physically active males rested for 30min prior to exercise, performed 60min of aerobic exercise at 60% V̇O and passively recovered a further 60min post-exercise. T and T were measured at 5min intervals during each condition. Mean differences between T and T were 0.61°C during pre-exercise, -1.78°C during exercise and -1.00°C during post-exercise. The reliability between the methods was low in the pre-exercise (ICC=0.49 [-0.09 to 0.82]), exercise (ICC=-0.14 [-0.65 to 0.44]) and post-exercise (ICC=-0.25 [-0.70 to 0.35]) conditions. In conclusion, poor agreement was observed between the T values measured through IRT and T measured through a gastrointestinal telemetry pill. Therefore, T is not a valid substitute measurement to gastrointestinal telemetry pill in sports and exercise science settings.

An Overview of Thermal Infrared Imaging-Based Screenings during Pandemic Emergencies

“…It is worth to mention that also other facial regions (e.g., forehead) have been demonstrated to be indicative of the core temperature. Anyway, in ecological conditions, such as large-scale fever screening, the inner canthus is proved to be less sensitive to external confounding, such as the environmental temperature, the employment of make-up and sweating [ 74 , 75 ].…”

Evaluation of a Wearable Non-Invasive Thermometer for Monitoring Ear Canal Temperature during Physically Demanding (Outdoor) Work

“…Next to metabolic heat production from the physical work, the two main factors influencing heat stress are the environmental conditions and use of personal protective clothing (PPC) and PPE [ 1 , 5 ]. Working in hot (sunny and humid) environments causes the body temperature to increase as a result of the inhibition of body heat loss [ 1 , 3 , 4 , 6 , 7 , 8 ]. Wearing full-body PPC and PPE hinders heat removal and so stimulates and increases heat stress as a result of thermal insulation and evaporative resistance [ 1 , 2 , 9 , 10 ].…”

“…Second, imprecise alignment in the ear may result in measuring the aural temperature instead of the ear canal temperature [ 33 , 34 , 36 , 37 ]. Third, if the insulation of the thermometer is insufficient in the ear [ 1 , 5 , 6 ], it is possible for the environmental or local temperature to influence the measurements [ 23 , 34 ]. To summarize, the Cosinuss° °Temp thermometer may form the basis for a non-invasive, non-obstructive monitoring system for workers with physically demanding (outdoor) occupations.…”

Effects of heat on behavioral and physiological mechanisms of the human thermoregulatory system during rest, exercise, and work

“…For instance, factors such as land leveling and soil moisture can locally affect grape production by up to 50% within the same vineyard. 173 Thus, productivity at a certain time of the day (e.g., when heat levels are at maximum) also reflects the amount of crop that is available for picking at that time which, as mentioned above, can vary by up to 50% within the same piece of land. This, in turn, can distort the final productivity assessment of the workers, and the conclusion on the effect of workplace heat on productivity.…”

“…Time-motion analysis combined with physiological data can be valuable in assessing the physiological strain of workers during period of increased occupational heat stress. 174 Time-motion analysis includes analyzing movement and the time spent on each movement through video analysis. This method is very powerful, since the investigator can analyze every second spent by each worker during every work shift, thus accurately assessing WTL without bias.…”