Happened when I was working at Nortel: I didn't do any exercise, I was so not in shape. Until my coworker Basvi made me try the new kickboxing class at the company gym. Twice a week for one hour, total torture in the beginning but it always felt so good after the class. After a while I noticed a change, I wasn't totally exhausted afterwards, and better yet my shirts were getting tighter at the shoulders. Something was happening.
These Jivoni's Jam classes included a lot of cardio exercise, pushups, situps etc in addition to kicking and boxing. And kicks and punches are not just done in the air, but you actually hit the pads held by your partner, or sand bags in well-equipped gyms, which makes it all the more fun. It is excellent stress relief, in addition to excellent exercise.
After quitting at Nortel I continued Jivoni's classes at world champion Cung Le's gym once a week, all the way until I left the USA. My getting in much better shape is all thanks to Jivoni, who helped me find pleasure and fun in sweating.