In recent decades, there is a broad consensus in the literature that heat-related mortality overall has declined relative to the magnitude of the heat event. This said, as society is aging and the climate is warming, it is uncertain that this trajectory can be sustained moving forward, particularly as historically rare events become more common. To explore more recent trends, using a recently extended data set, we explored trends in anomalous mortality associated with extreme heat event days for the period 1975-2018 across the largest 107 metropolitan areas of the United States. We defined heat using an excess heat factor, and once events were identified, used a distributed-lag nonlinear model (DLNM) to assess mortality response over a cumulative 10-day period. In addition to total mortality, we also assessed subsets of those 65+ and 45-64, each of which were subdivided by sex. Results indicate that, overall, heat-related mortality associated with any given heat event day is decreasing. The most substantive decreases in mortality are those 65 and older, which may be associated with greater awareness as well as that population being the target of most intervention systems. Indeed, in many locations heat-related mortality among women 65 and older is no longer statistically significant. In contrast, while overall rates are lower, such trends are not seen in those aged 45-64. In particular, there is an increase in mortality among men 45–64 of 11.3 deaths per year across the US, most concentrated in southern and southwestern US cities. Overall, however, the general decreases in heat related mortality are being offset somewhat by the increase in heat event days, particularly since 2010. Given the impacts of the heat events since 2018 over the US West in particular, it is clear that heat-related mortality is not something confined to the past.