I started pool running 10 years ago when I injured my back. I thought I'd be bored out of my mind doing it, but I quickly found ways to make it fun. Since that time, I've made pool running a regular ...
Your existing pump likely works fine. What you need is proper heating equipment matched to your pool size and usage patterns.
Swimming and running are both excellent forms of cardiovascular exercise. After all, they account for two-thirds of a triathlon. Both are great ways to boost your cardio fitness and burn calories.