Three minutes of high intensity freestyle on the heavy bag is a good start.
The more acrobatic leg drills are even better if done for a prolonged period. A lengthy series of aerial kicks, low sweeps and tumbles gets the cardio going quickly because you use the largest muscles in the body to move your entire mass around--harder to do than sustained punching drills and even harder than most sparring for the same amount of time.
"Look, I'm only doing me job. I have to show you how to defend yourself against fresh fruit."
For it breeds great perfection, if the practise be harder then the use. Sir Francis Bacon
the world has a surplus of self centered sh1twh0res, so anyone who extends compassion to a stranger with sincerity is alright in my book. also people who fondle road kill. those guys is ok too. GunnedDownAtrocity