> The problem is that the first I in HIIT is much too much Intensity for some. Fitness clubs had to get rid of or gate HIIT machines because guests would vomit. If you're doing it right, you will be anaerobic, many people don't tolerate that without working up to it, and people hate working up to things.

A lot of people just can't go from sitting on their buts all day to sitting on their buts all day with the addition of a daily vomit enducing HIIT routine. They would explode.

Probably best to start by walking, then walking briskly, etc...