How many people die from heat-related illnesses? The truth is, we don't actually know

Reporting heat-related deaths isn’t as straightforward as one might think. If someone dies of a heart attack in a sweltering apartment, should it be recorded as a heart attack or a heat-related illness? And if you can’t get accurate numbers as to how many people are dying, how can you put mitigation measures in place to prevent these deaths in an ever-warming world?