No time to work out? Katz doesn't buy that excuse. Exercise shouldn't be something that we're "making time" for, he says. It should be a daily given, like sleep or eating. "If you want a lifetime of robust health, you have to be religious about your physical activity," Katz says, which, according to HHS, means getting 2 1⁄2 to five hours of moderate cardio, or 75 minutes to 2 1⁄2 hours of intense cardio, each week, plus weight training twice a week. But that doesn't mean you have to slog it out on a treadmill at the gym. Pick a truly enjoyable activity and a workout partner if you can find one that will make you sweat and that you can commit to, says Katz. "Put on music for half an hour every evening," he says, "and dance around your house!"