The “Heat and Health” page of the Lancet Countdown presents annually updated global data on how extreme heat affects human health and well-being. It features a series of scientific indicators that track trends in heatwave exposure, heat-related mortality, labor capacity loss due to heat stress, and the health system’s preparedness. The page includes visual data tools, country-level dashboards, and summaries of regional impacts—making it a key resource for researchers, policymakers, journalists, and public health professionals. It emphasizes the disproportionate burden on vulnerable populations such as infants, older adults, outdoor workers, and low-income urban communities. The indicators are based on peer-reviewed research and are part of the Lancet Countdown’s broader initiative to monitor the health impacts of climate change. Users can also explore policy recommendations, access underlying datasets, and download the full report for use in policy and advocacy. The page underscores the urgent need for adaptive and preventive responses to rising global heat exposure.