swimmings actually the best, cuz it the most effort. But i like to bike to work and back, doin that everytime u work keeps ur heart in good shape. Id say joggin to, that works well, but u don want to run (u lazy bum )
for example, you run for 2 minutes,you walk for 30 seconds, you run for 2 minutes,you walk for 30 seconds. The 2 minutes that you run,your heart rate goes up,when you walk the 30 seconds your heart rate is still up for its like you're still running.this will build everything in you up.