What do you mean "miss" a workout? Is this different than a scheduled rest day? To be brutally honest, I can't remember the last time I didn't break a sweat at least once a day. It's either cardio or training for me....everyday.........gym is closed? I hit the streets..........always something to keep going............other than that, I schedule a day of once a week..........but cardio still on that day.........my .02, if you are lazy - sack up and go. If you REALLY have the flu, stay the hell out of the gym....at least mine anyways,,,,,,lol....