Energy balance is the basis for studying climate and the same principles represent the foundation of understanding human heat stress, which is similarly governed by radiative and sensible and latent heat fluxes, as well as by metabolic heat generation.  Consequently, the basis exists for using between basic principles in atmospheric thermodynamics and dynamics to understand the prevalence and intensity of human heat stress in a changing climate.  Temperature is one key variable in determining human heat stress, but as is obvious from the general framing as an energy balance problem, atmospheric humidity, wind speed, and radiation loading are also important. I will provide some background on the historical development of these concepts and then bring them up to date and show how parts of the problem of understanding and predicting future moist heat waves and heat stress looks very much like the understanding the dynamics and predicting the future of monsoons.  Some parts do not. Reality is complex and we must embrace that too.  I will show how methodological choices have deeply biased much of the heat stress prediction literature and suggest some easy to implement best practices. I will then present some applications of future moist heat stress prediction to impacts on human health, labor capacity, and the associated global economic impacts with an emphasis on poverty and developing nations.