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Thermal balance between the body and the environment is a precondition of thermal comfort. This balance depends on the bodily heat generation due to metabolism and heat dissipation to the ambient. Various thermoregulatory mechanisms are in place to adjust the latter in response to changes in the former and maintain the balance. Otherwise, thermal discomfort occurs due to a sensation of warmth or cold, depending on in which direction the balance is tipped. This short paper uses basic thermodynamic models to examine the role of cycling speed in improving thermal comfort. The effect of higher speed on both metabolic heat generation and heat dissipation is examined for various road and environmental conditions to determine whether cycling faster could provide relief from thermal discomfort. The results suggest a net cooling effect, desirable under heat surplus, is unlikely to be achieved. A net heating effect, on the other hand, can be achieved for mildly cold conditions., Competing Interests: Declaration of competing interest The author declares no conflict of interest., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

A versatile meteorological index for predicting heat stress in dairy cattle remains elusive. Despite numerous attempts at developing such indices and widespread use of some, there is growing skepticism about the accuracy and adequacy of the existing indices as well as the general statistical approach used to develop them. At the same time, precision farming of high-yielding animals in a drastically changing climate calls for more effective prediction and alleviation of heat stress. The present paper revisits classical work on human biometeorology, particularly the apparent temperature scale, to draw inspiration for advancing research on heat stress in dairy cattle. The importance of a detailed, mechanistic understanding of heat transfer and thermoregulation is demonstrated and reiterated. A model from the literature is used to construct a framework for identifying and characterizing conditions of potential heat stress. New parameters are proposed to translate the heat flux calculations based on heat-balance models into more tangible and more useful meteorological indices, including an apparent temperature for cattle and a thermoregulatory exhaustion index. A validation gap in the literature is identified as the main hindrance to the further development and deployment of heat-balance models. Recommendations are presented for systematically addressing this gap in particular and continuing research within the proposed framework in general., (© 2022. The Author(s).)