Last Sunday, I wrote about the virtues of building more muscle, particularly as a way to stave off the aging process—or even turn it back. In focusing on muscle mass, I don't want people to get the idea that it's the only important factor in health and performance. Cardiovascular fitness is just as important. You need the aerobic base to build the rest of your fitness. That's why I've always been saying that lifters need to build an aerobic base and endurance athletes need to lift. The better your aerobic function is, the more capillaries you establish, the more blood you can deliver to tissues, and the more work you can do. The larger and more robust your aerobic base, the more low level work you can shunt off to it, and the more high-end power you can reserve for intense movements engaging the fast twitch muscle fibers. Plus, that aerobic base will grow to encompass far more than you can imagine. When you start out, maybe the aerobic threshold—heart rate of 180 minus your age—looks like a brisk walk. Perhaps a hike through hilly terrain. Maybe even an easy jog. As you build that base and extend that threshold, though, what's "easy" starts looking more and more impressive. Pretty soon, you can do a brisk jog and maintain that aerobic heart rate. You can start ascending those hilly hikes at a faster pace and still be under the threshold. You can start adding weight to a backpack and maintain the aerobic threshold. What's easy and aerobic to you gets faster and faster. If I had to choose just one? I don't. That's not the way this works. The fact remains that building muscle the right way will also support the improvement of your cardiovascular fitness. It's also true that building cardiovascular fitness in the proper manner (by building the aerobic base through lots of low level aerobic activity maintaining a heart rate of 180 minus your age) will support the increase of your muscle mass. The two aren't mutually exclusive—they are obligatorily inclusive. Now, get out there and run, or walk— whatever works for you. Let me know what you do to build your aerobic base in this week's New and Noteworthy. | 
