text: Buy a skipping rope.  Skip for a couple of minutes, several times during the day, you can do it rain or shine.  Dogs won't chase you down the street.  You won't trip on ice, stones etc.  It is not expensive.  It gets your heart rate going faster than tread mill and takes up less space when you put it away.  You can also take it travelling with you.\nIt develops secondary skills, balance, ever seen a fat boxer?