I don't think the impact is very high in Timesaver and is comparable to Cardio and Weights. The only exception is the hi/lo portions of SJP which are on one of the 5 Timesaver workouts. The rest of the cardio is the step sections of Step, Jump, Pump and Step Blast. There's also kickboxing from KPC, but you can leave the jump kicks out of it.
Diane