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.