Okay, let's suppose you're on a split routine where you're doing chest/back/calves.

Rather than doing :

Chest : 3 sets of 8
Back : 3 sets of 8
Calves : 3 sets of 8

wouldn't it be more efficient to do giant sets ie. :

{Chest 1x8 -> immediately go to Back 1x8 -> Calves 1x8 } rest x3

I would think that workouts would go by quicker and your heart rate would stay elevated longer.

What would the disadvantage be? Running out of breath if the exercises are too large? Is there some principle that suggests that the second set can't be too long after the first on a particular exercise?