John Wayne is said to have chain-smoked 5-7 packs a day? If you can smoke a cigarette every ~30 mins, that's 2/hour (actually about 1.5 packs/day), but if a cigarette takes 10 minutes to smoke and you chain-smoke, that's 6/hour (4.5 packs/day). So it's doable but John Wayne was significantly out of breath the last 10+ years of his life, perhaps from having an entire lung removed.

A lifelong chain smoker will smoke a cigarette in 1-2 minutes and light up another. 3-5 minutes is a relaxed casual smoke. Cigarettes were modified a decade or so ago to ensure that they go out quickly if not actively smoked. It's not even possible anymore to keep a cigarette burning for long enough for it to take 10 minutes.

This is all pedantic. The point is that you can chain smoke quite a lot if you're dedicated. I've never met anyone who smoked more than two packs a day regularly or maybe three on a crazy night out of drinking and smoking. 4-5 is crazy.

Lucille Ball's voice changed dramatically over the course of the 6yr show from heavy smoking. Their show was sponsored by cigarette companies and she used to hand out cigarettes on a platter to guest when they came over to her house.

had one lung removed, and the other was probably close to worthless from smoking