Swimming is misunderstood

At my yearly physical last week a funny thing happened. The doctors staff informed me that swimming is not an aerobic exercise and that I would be better off walking briskly for 20 to 30 minutes a couple days each week. I explained I try to swim 2 to 3 times each week for 60 to 90 minutes,and my workout is prepared by MO, ya'll might recognise that name. They asked me the distance I cover in that time and I responded with 2800 to 3500 yards or 1.5 to 2 miles depending on time. Not good enough according to the staff. I should be walking. I will let the facts stand for themselves. Age 48 Wt 149 BP 120/80 Pulse 60 Body Fat 18% Total Cholesterol 194 (need to eat better) Well it is off to the pool for another MO workout. Maybe I will walk briskly from my car to the pool and see if that counts. Thanks for those workouts MO I enjoy them. Have a great day Paul