"Depending on how intense your workout will be, a warmup can be anywhere from five to 15 minutes," Lyuda said. To prepare your body for a run, simply go for a quick jog to get your heart rate up, then follow that with some dynamic stretches (more on those ahead). "For a more intense [or longer] workout, spend more time on the warmup run, gradually increasing your speed, before doing your dynamic stretches," she said.