I dont get it

I have the same problem. I have a heart arrhythmia, Was told a lot of people have it without even knowing. Let your Dr. know the problem your having and see what he or she say's.

The cardio is improving your heart rate. It is harder to jog because your body is probably fatigued.

The PVC will do it. If you have a follow up with the Cardiologist let him know or just call and talk to his nurse and she will tell you what you can do. The PVC has nothing to do with the Plumbing of the heart it has to do with the Electrical part. Exercising will not improve that part.

Running can be aggressive at strengthening your heart and helping your body to regulate its use of oxygen, which means that the more you do it the faster you'll recover after a routine. It sounds like you're still in the 'conditioning' phase of becoming a runner. A lot of things can factor in to your first workouts, especially while you're getting your body to that first plateau. The biggest factors are physical ability and mental endurance. Focus heavily on your running form - keep your arms swinging from the shoulder, not from the elbow; arms should swing back and forth, not crossing your chest; you should pick your knees up in rhythm with your arm swings; don't let your upper body lean forward or backward, you shouldn't be stiff, but you should try to keep upright; when starting out it's also a good idea to try to inhale every three steps and exhale every three steps. Stay relaxed. The better your form and the more relaxed you are while running the less energy is wasted, the longer you'll be able to run. Think positive while you're running, too. Mental endurance is a huge factor in having a good run. It's easy to get out there and start thinking negatively and focusing on the discomfort of running. The more positive you are, mentally, the further you can run. And, don't worry about speed when you're first getting going. While working on conditioning, it's most important to focus on how long you are running. Maybe give yourself goals, like run every other day (so 3-4 days a weeks) pic two of those days to do a 15 minute run and one day to do a 20-30 minute run. As you get more comfortable add more time.