I have pectus excavatum and my heart is turned in such a way that it is not able to effectively pump when I exercise. As a result I get dizzy and nauseous. I had a baby about 1 1/2 years ago and I am unable to get rid of an extra 20 pounds. How can I do that without overexerting? Don’t I need the cardio in order to lose weight?
Have you ever thought of aquatic exercise? In the water, your heart does not have to work so hard. One theory is that the buoyancy of the water assists in venous return to the heart with less effort, another that the cooler environment requires less effort for thermo-regulation. The result is that the heart rate in the water tends to be lower even for the same rating of perceived exertion.
If this is an option for you, I would try this in a supervised setting so that somebody can be there immediately if you are not well.
I wish you good luck.