In this decade of your life, you may start to detect the physical signs of aging. "In your thirties, you should aggressively work on prevention," says Jordan Metzl, M.D., a sports medicine physician at the Hospital for Special Surgery in New York City. In addition to the obvious health benefits of healthy eating and exercising, "you can ward off the signs of aging, look better, and even feel the psychological perks of healthy living," says Dr. Metzl.
"What you do now makes a huge difference in the aging process," agrees Miriam Nelson, Ph.D., author of Strong Women Stay Young and director of the Center for Physical Fitness at the School for Nutritional Science and Policy at Tufts University. "If you're not active now, the changes aging brings will be more pronounced later," she warns. Even though the natural aging process robs us of bone density and muscle mass, exercise and nutrition can keep you stronger and healthier. "Let's face it, a coach potato at age twenty-five is in a lot worse shape compared to a fit thirty-five-year-old," says Dr. Metzl.
Exercise your lungs, and you won't even notice you've hit the big 3-0. Choose an activity you enjoy that gets your heart rate up to approximately 70 to 80 percent of your maximum heart rate and stick with it for 30 minutes a day at least three times a week. Exercise at an intensity where you can pass the talk test, advises Nelson: "You should be able to speak, even though your breathing is rapid."
"The body gradually loses about one-third of a pound of muscle and replaces it with fat," says Nelson. But weight training two to three times a week can make you stronger than ever and minimize your muscle loss. Each weight-training session in Nelson's program consists of eight to 10 repetitions of six to 10 exercises that target all of the major muscle groups.
Use it or lose it is the mantra when it comes to flexibility. Join a yoga class or invest in some personal stretch time; you'll feel less stressed and tense. "Stretch after your exercise sessions," advises Nelson. "If you don't, you'll decrease your flexibility." The American College of Sports Medicine's guidelines recommend four repetitions of static stretches—held for 10 to 30 seconds each—per major muscle group (arms, shoulders, chest, abdomen, back, hips and legs) at least two or three times a week.
Strength training can significantly increase your metabolism, says Nelson. She recommends weight training two to three times a week (do two sets of eight to 10 repetitions, six to 10 exercises each session). By building lean tissue with weight training, you'll avoid a shift in your fat-to-muscle tissue ratio and speed up your metabolism.
This decade marks the start of gradual bone density loss in both men and women. You lose approximately 1 percent bone density each year, notes Nelson, so it's vital to get proactive. "Strength training and impact exercises (such as jumping, stepping, and plyometrics) will stave off skeletal weakness," she says. Also, thirtysomethings reach their bone peak mass between the ages of 30 to 34, says Susan Kleiner, Ph.D., R.D., author of Power Eating. "At this point, the bones won't 'grow' anymore," she explains. Therefore, "Your goal should be to maintain your bone mass by getting plenty of calcium from your diet," she advises. If you don't, you'll end up dipping into calcium reserves that reside in your bones—something you'll want to avoid, because "it's not easy to replace what you've lost," says Kleiner.
You may start to slow down, but with adequate training there's no reason you shouldn't be making personal bests. Dr. Metzl advises mixing up your routine a bit by "adding sprint work a few times each week." He says you can incorporate sprints into your running or biking regimen.
In your late 30s, your body needs fewer calories, says Samantha Heller, R.D., senior clinical nutritionist at New York University Medical Center. However, it's essential that women of childbearing age get plenty of folate and B vitamins (found in dark green vegetables, fortified orange juice, some cereals, dried beans, and peas), says Heller. Don't forget to down water, eat complex carbs (whole grains), and load up on vegetables, legumes and soy products. "The earlier you start good habits, the easier it will be later," assures Heller. "Eating a healthy diet will keep your weight down, ward off signs of aging, prevent disease—and give you an energy-packed vital life," she adds.