Whether your incentive is winning your age group, earning a whole new set of PRs, or being the hottest mom or dad on the PTA, running not only allows you to age gracefully, it enables you to redefine aging. While your friends dread the big "4-oh, no!" you can say, bring it on. Still, if you want to stay healthy and keep accumulating finishers' medals, you do need to realize that you aren't the young colt you once were. Watch your mileage, take rest days, and cross-train, strength train, and stretch regularly.
You can continue to take pride in your Lance-like resting heart rate, which won't change as you age. Though your heart rate declines a bit (somewhere between .7 and 1 beat a year), its influence on your performance is minimal. As with every decade, VO2 max continues to dictate how effectively you can push the pace. At least one element that determines VO2 max is out of your control—your heart's pumping ability naturally slows.
However, you do have influence over three other factors: your muscle mass (the more muscle, the higher your max), body composition (the more fat, the lower it is), and training frequency and intensity (the less you push, the more it falls). This means you can offset the drop of your VO2 max with strength training and speedwork. The payoff? Not only can you reign over your local masters division, but you'll also surpass runners half your age. You also have a secret weapon: your hard-earned savvy. "People underestimate the cognitive part of running, but mental toughness isn't genetic—it's honed through experience," says sports psychologist Bradley Young, Ph.D.
Starting at age 40, your kidneys are less likely to conserve water as you dehydrate. And the nerves in your mouth and throat that tell you you're thirsty don't function as well. So remember to hit the water stops in races and carry a bottle while training. Bones are deteriorating faster than they're forming. The loss hits women harder (from 30 until menopause, women lose one percent a year), but men aren't immune. Researchers studied the bone density of runners' spines and found that males had similar density losses as females. Take note: Those who strength trained had the best density scores.
Midlife crisis have you reaching for your Asics for the first time in years? Give yourself time to get into the groove. "If you start running too fast or too much, you're inviting injuries," says Bill Roberts, M.D., the medical director for the Twin Cities Marathon in Minneapolis, who recommends two to four years of regular running before taking on a marathon. "The earlier, the longer, and the more consistently you run, the more resistant you are to injury." Runners who have been faithfully lacing up their shoes for decades need to watch out for the I'm-old-so-I'm-slow trap. Throw in some intervals to remind your muscles and your mind that you still have a fourth (or fifth) gear.
"As you age, every calorie should be as nutrient-dense as possible," says nutritionist Lisa Dorfman. Replace white carbs—bread, pasta, rice—with whole-wheat versions. If you're starting to feel some aches and pains, especially in your knees, consider taking the joint supplements glucosamine and chondroitin. Studies have shown that consuming 1500 milligrams (mg) of glucosamine and 1200 mg of chondroitin daily can ease joint pain, says Dorfman.
James Sheremeta, 44, La Jolla, California
Running since: "When I was young, I ran in circles until I fell over."
R&eactue;sumé: Consistent top finisher in 5-Ks to marathons. Second overall at the 2007 America's Finest City 5-K (15:57); first master and fourth overall at the 2006 Saddleback Memorial Half-Marathon (1:14:21)
What I've learned: "When I turned 41, I noticed that I had to respect recovery more. So now I tone down my all-out efforts. And if things aren't going well in a workout, I pack it in and don't push it. I run 90 miles a week and aim to be a top competitor. Once I can't do that, I'm going to focus on the experience and travel to new places to run."
What works for me: "I started pool running in 1996 to recover from a stress fracture. I replicated my training schedule exactly, and just two weeks out of the water, I came in fifth overall at a marathon with a 2:28:12."