I don't get it either. But I assume he meant lifting heavy weights with high intensity i.e. shorter rest periods between sets.
Still, having a higher heart rate for a few minutes or so seems like revving your car's engine hard for the same time frame. Although that's a weird analogy since we're not machines but from a logical standpoint the professor might have a point.
Although I think that the pros far outweigh the cons when it comes to weightlifting, especially the strengthening of the bones, which is essential for evading the dreaded osteoporosis as we get older.
