How can a person guard against a decrease in heart and lung function?

One way someone can guard against a decrease in heart and lung function is by doing cardio. You can do running, or any sport. It will increase your blood flow (hope this helps)

If it's a smaller child or infant, place one on the middle of the chest and on the child's back. (if it is a bigger child with enough room for two, place one on the upper right/your left of the chest, and one on the lower left/your right) the pads should never touch each other.