Shoe microclimate (temperature and humidity) has been suggested to contribute to perceptions of foot thermal comfort. However, limited data is available for perceptual responses in relation to shoe microclimate development both over time and within different areas of the shoe. This study evaluates perceptions of foot thermal comfort for two running shoes different in terms of air permeability in relation to temporal and spatial characteristics of shoe microclimate. The temporal characteristics of shoe microclimate development were similar for both shoes assessed. However, higher temperatures and humidity were observed for the less permeable shoe. Changes to shoe microclimate over time and differences between shoes were perceivable by the users.This study provides the most detailed assessment of shoe microclimate in relation to foot thermal comfort to date, providing relevant information for footwear design and evaluation. physical activity where the feet are enclosed in shoes for extended periods of times i.e. marathon runners (Auger et al. 1993). Intermediate levels of moisture have also been shown to increase coefficients of friction which have been found to influence the probability of blister formation (Sulzberger et al. 1966). Changes to the shoe microclimate therefore encourage the growth of microorganisms which can lead to odour development and to poor foot health. Knowledge regarding the subjective evaluation of shoe microclimate is limited, with little published information available. Although subjective perception of foot may not always coincide with measured foot (Barkley et al. 2011), local discomfort has been attributed to elevations in temperature rather than elevations in the moisture content both within hiking boots (Arezes et al. 2013) and within sock and boot liner materials worn within protective footwear (Irzmanska et al. 2013). The influence moisture has on foot comfort therefore requires further investigation as it is unknown whether changes in temperature and/or humidity help an individual in determining perceptions of thermal comfort. Despite the impact shoe microclimate has on foot health and foot thermal comfort, to our knowledge no quantitative shoe microclimate data is available over time, within different areas of the shoe or in relation to perceptual responses specifically for sports related footwear. With exercise, metabolic heat generation and sweat rates are high and so balancing the amount of heat supplied to or generated by the feet with heat loss becomes crucial. Currently, only changes to foot during running have been reported (Barkley et al. 2011; Shimazaki and Murata 2015; Shimazaki et al. 2015). During a 30 minute running bout at 12 km hr -1 temperature elevations from rest of 8.2°C were observed at the heel and 4.8°C at the neck of the big toe, foot regions associated with high contact loads and pressure during running (Shimazaki and Murata 2015). Increased ventilation within running shoes has also been shown to produce a cooling effect, reducing foot elevations, particula...