Heat transfer controlling the temperature of human forehead at rest and during walking

Aiming to improve the reliability of current fever screenings based on the measurement of forehead surface temperature, we examined the heat transfer of the human forehead on the basis of our proposed one-dimensional heat transfer model, focusing on the impacts of walking on the regulation of forehead temperature. Walking experiments showed that the forehead-surface temperature decreased until the heat conduction inside the forehead reached a steady state after at least 6 min of walking in the absence of shivering and sweating, and the temperature decrease during walking was almost proportional to the temperature difference between the forehead surface and the environment before walking ( T s0 − T e ). The temperature difference between the prefrontal cortex and forehead surface in a thermally steady state during walking was well estimated by the one-dimensional model when the local forced convection heat flux due to oncoming air to the forehead was approximated with the heat flux at the forward stagnation point of a heated circular cylinder immersed in a uniform flow. The model also provided a theoretical estimate of the decrease in the forehead-surface temperature until the heat conduction reached a thermally steady state, as a function of T s0 − T e . Thus, we could confirm the validity of the model to analyze the heat transfer of the forehead during walking. These results provide a scientific basis for the use of forehead-surface temperatures in fever screenings at airports where fever screening is usually conducted just after or during several minutes of walking. • One-dimensional heat transfer model of human forehead during walking is presented. • Heat conduction within the forehead reaches a steady state after 6–7 min of walking. • Temperature drop on the forehead surface during walking is estimated theoretically. • Temperature difference between PFC and forehead surface is accurately predicted.