Yes, charging at warmer temperatures over the long run has a negative effect on battery life. But many of the common charging behaviors are less than ideal. The most common probably being that frequent top-off charges are ideal, but not possible a lot of the time. I've been doing many these things for as long as I've been using smartphones. 5 devices over the course of 7 years or so, and I've never had a battery fail during the time I've been on a particular device.
And charging while using Nav? You practically have to, if you are doing a long drive. Otherwise, your battery is going to be too low to do anything by the time you get to your destination. I also charge while using WiFi hotspot for similar reasons. If you don't charge while doing power-intensive activities, the phone isn't going to have any charge when you need it.
---------- Post added at 03:20 PM ---------- Previous post was at 03:15 PM ----------
But even so, I rock climb and ice climb. Not constant high speed movement like a marathon runner, but very intensive, all day activities nonetheless. I can down some power bars of power gels and keep going, no problem. To not do so, would invite disaster (running out of power when you need it the most). There are other activities, like adventure racing and long distance biking (and others) where they do the same thing. Yes, you can't eat a cheeseburger while doing a dead spring. But you can down enough calories and carbs to keep your body going, while doing some of the activities I mentioned.