As I try to spend some time outdoors, I have developed a little routine of sprinting from one lamp-post to the next on my street, and then walking back to the first one, and repeating the sequence 5-6 times. It's a form of High Intensity Interval Training (HIIT) which has proven to help shed fat and improve VO2 capacity more effectively than traditional cardio. Of course, if there are underlying health issues please only do this after discussing with your doctor.