Sure before air conditioning was common, people coped with the heat. But there were a few differences between then and now besides the lack of A/C
When it got really hot people would sleep outside - on porches, lawns, city parks… 1995 was not the first time the Chicago lakeshore had people camping out to beat the heat at home. In Detroit, Belle Isle used to have folks sleeping on it in the worst of summer heat.
Back then, EVERY building had windows that opened - even office buildings and skyscrapers. Not like the hermetically sealed buildings from the 1970’s onward.
People DID die of the heat in the old days… just not in massive numbers. Partly, this was because folks had a little more respect for the heat and adjusted activity levels accordingly. This is unlike a couple of the '95 victims who insisted on continuing their dailly jog in 100+ heat.
Back in the old days, folks did not, on average, live as long or with some of the chronic diseases now seen. Folks with heart disease or severe respiratory problems were less able to survive any weather-induced stress. In '95, at least some victims were frail, chronically ill folks whose power and A/C failed.
Yes, social ties are also important - if family or friends are around they might notice grampa has passed out and start trying to cool him down, take outside into cooler air, seek medical attention, etc. as opposed to gramps continuing to bake alone in a closed up apartment. As mentioned, Chicago now offers to perform “wellness checks” on folks in extreme weather - gramps can put himself on the list and thereby increase the chance of him being found if something happens.
There’s also the matter of adaptation. The human body WILL adjust to heat… with time. If you live where it’s hot all year round you’re body will be better able to cope than someone who just flew into the area from a colder climate. When, for instance, it’s spring and I’ve been used to freezing temperatures for several months a temperature of 75 degrees (about 23 C) will leave me overheated and sweating. This time of year, 75 seems a tad chilly and I don’t feel knocked over by the heat until it’s up around 85 or 90 (what Europe is currently experiencing). In 1995, after 100 degree days, 80 started to feel pleasently cool. But as I said, it takes time to adjust.
Heat can kill, but how folks get into that circumstance varies. Which is why it’s so tempting for governments to deny there’s a problem - it’s not a quick, easy, one-time apply fix here sort of problem. There are multiple factors, including individual health and age. And you can’t change the architecture of a city overnight, you have to deal with what’s there. Folks who have never experienced a certain form of weather just won’t have the coping skills - they can learn, certainly, but again, it takes time.
I really do feel sympathy for Europe - that kind of heat is miserable. I hope you folks get a break in the heat soon.