what is everyones thoughts on alternating running/lifting during a workout. I like running like 5 minutes at a decent pace, then going and doing two or three lifts while my heart rate is up, then running another 5 minutes, then lifting again, then running again. am I getting anything out of this more than just running for 15 or 20 minutes then doing all the lifting? maybe I lift too light because I feel like my heart rate isn't always up high enough.