A、Wearing arm weights while you are swimming. B、Jogging vigorously in one place for a long time. C、Using bicycles that require y

W: Exercise, exercise, exercise! We hear so much about it these days that even the experts can’t agree on which exercises are best. Now some doctors are strongly encouraging arm exercises.
M: Arm exercises? I’ve never heard of that. Is that because our arms are too fat or flabby?
W: Actually, that’s not the main reason. They say that arm exercises are an ideal way to become physically fit.
M: But don’t arm exercises raise your blood pressure? Seems I’ve read an article about that before. So, that’s risky.
W: Not really. That they do, but the article I read mentioned several ways that can compensate for that.
M: Really? How?
W: By adding leg exercise so the arms don’t do all the work. Arm exercises alone aren’t enough to increase metabolism before fatigue sets in. The more of a body that involves in the exercise the better.
M: And in turn, I’m sure that there is a great chance of losing weight, right?
W: Sounds right to me.
M: So, what exercises do the experts recommend?
W: They mentioned quite a few. But some of the more popular ones are cycling with special bicycles that make you use both your arms and legs, and walking vigorously while wearing arm weights.
M: Sounds great. I must try that. You know, I like to walk a lot.
23．According to the conversation，what is one problem with arm exercises?
24.According to the conversation, what are the experts now recommending?
25.What form of exercise does the woman mention?