You’ve managed to make it to spinning class (for the third time this week!), but the minute it’s over, you beeline for the door. Hold it right there—you may want swap your spin time for more reps in the weight room. Researchers at the University of California, Los Angeles found that the more muscle you have, the longer you’ll live. Clocking too much sweat time on the bike (or any other cardio machine) may help blast fat, but it will hinder your ability to put on life-prolonging muscle. Need more reason to pick up the weights? Muscle gives you an edge over fat: the more muscle you have, the more fat you’ll burn, even while at rest. Bottom line: don’t neglect lifting on your fat-loss journey.