This subject intrigues me. Every smoking person who has tried my eCigs hasn't had this problem.
There is only one person I've experienced who couldn't seem to stop coughing every time she attempted vaping. She had severe COPD and later was diagnosed with advanced end stage Lung Cancer. As badly as she wanted to vape, she couldn't. Her Son spent hundreds on hardware she couldn't use... but she still smokes.
However!.... My Mother has severe COPD (is on Oxygen 24/7) and can vape with no issues whatsoever, so this has me somewhat stymied.
Could it be 'sensitivities' or a type of allergic reaction to PG or VG?
Prior to vaping I hadn't smoked for 3 years. I took a puff off of a traditional cigarette and couldn't catch my breath for what seemed like several minutes. It was scary. Vaped out of the gate with no problems whatsoever, and I vape 24mg Nicotine strengths and require tremendous throat hit.
I really wish I could understand 'why' some people just can't seem to 'tolerate' vaping