Where to begin? That is the key question for most newcomers to a fitness facility or training program, especially for those who were previously sedentary. Should a person start slowly, with 30 minutes per day of treadmill walking? This amount of activity is in line with public health recommendations that healthy adults should accumulate 30 minutes of moderate-intensity exercise on most, if not all, days of the week (Haskell et al., 2007). Or should a newcomer complete shorter bouts of high-intensity interval training (HIIT)? After all, a perceived lack of time is often cited as one of the primary reasons people drop out of exercise programs (Salmon et al., 2003). Or should it be some combination of the two?

Source: ProSource: Research Special HIIT vs. Steady-State Training – ACE