CURRENT REGIMEN: Strength training, 2-3 times/week

“The older we are, the more important strength training becomes,” says Mohr. That's because working through exercises that exhaust your muscles keeps them strong, shores up the connective tissue around your joints, and builds the bone density that wards off osteoporosis. Studies have shown that a regular weight-lifting routine can significantly slow the creaks and pains of aging — even among people who engage in regular aerobic exercise.

It also helps you enjoy daily activities. “I work with accomplished triathletes and runners who want to work out with weights so they have the strength to pick up and play with their kids,” says Hyman. “It doesn't necessarily help them in their sport, but it definitely improves their quality of life.”

What's missing

While there is a cardiovascular component to lifting weights — the panting that comes at the end of a hard set of lifts is your heart going into overdrive — you're missing out on the sustained aerobic benefits enjoyed by runners, swimmers, cyclists, elliptical-trainer users, and even walkers.

“A long, steady run of 30 to 60 minutes builds endurance,” says Hyman. By building stamina, you're teaching your body to handle sustained physical stress as efficiently as possible. And — wouldn't you know it — the better you can handle physical stress, the better you can handle mental stress.

The fix

There are a couple of options. First, turn your weight routine into a cardio workout. “If you're doing weight circuits [in which you move from exercise to exercise to complete one circuit, instead of doing three or four sets of the same exercise before moving to the next], don't rest between exercises,” says Holland. By not letting up, you'll keep your heart rate elevated throughout the circuit. “Just be careful to not push yourself too hard,” he warns. “You don't want to be out of breath. These aren't sprints.”

Second, take a brisk walk on a hilly route for an hour or so, ideally every day. That's easy if you're a dog owner. Hyman also recommends swimming. “In the pool, you take the weight off your body so it can enjoy a break, yet you still get a great aerobic workout.”

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