Which of these scenarios would provide the best help for improving cardiorespiratory health?
(a) Sam hurt his left knee when he was in the army. Although he'd like to be more active, Sam has a fairly sedentary lifestyle.
(b) Ana has a desk job and keeps a tight work-and-play schedule. She participates in 10 minutes of aerobic exercise during her lunch hour every Monday, Wednesday, and Friday.
(c) Shari has a hectic work schedule, which means gym time is limited. She has maintained a loose schedule of sporadic workout routines for three years.
(d) Carlton goes to the gym 4 days a week. Every two weeks he evaluates and upgrades his consistently challenging exercise.