Start running

No other exercise matches running for its ability to soak that sports bra. The stair-stepper, bike and other gym staples work you hard, but running blasts the most kilojoules: in a study done by the Medical College of Wisconsin and the VA Medical Centre, the treadmill (used at a “hard” exertion level) torched an average of 2 950 to 3 600kJ in an hour. The stair-stepper (2 660 to 3 200), rower (2 500 to 3 090), cross-country ski machine (2 500 to 2 835) and stationary bike (2 080 to 2 524) were all lower in overall kilojoule burn.

Running also gives your ticker a world-class workout. When your legs hit their stride they squeeze blood toward your heart, which in turn forces it to pump the blood right back. The faster you run, the harder your heart works and the stronger it gets.