Swimming with COPD

Question
I always enjoyed swimming underwater. I can no longer stay down. I was diagnosed with COPD. I noticed today in my pool that while being perfectly still in the deep end (I don't have to move a muscle to tread water) I can take a deep breath and my head and shoulders come out of the water. When I exhale my head will go under up to my eyelids. How can I retrain myself to swim underwater??? I miss it!!!! I am 53. Also- any suggestions for water exercises to flatten my tummy? I swim and walk the treadmill for a total of 2 hours every night and my tummy just stays the same little round pudge...

Answer
The best way to retrain yourself to swim underwater is to just do it.  The reason you bob up when you take a breath of air is the air is helping you float, when you exhale you sink because the extra flotation is gone.
There really aren't any water exercises to lose the little pudge.  Swimming is terrible for losing "fat" weight, the best thing for that is diet and crunches(half situps), leg lifts etc.  Bike riding, walking and other aerobic exercises are great in addition to your swimming.
Hope this helps,
George