A few years ago, personal trainer Anna Maltby cut back on exercise as she juggled work with being a new mother. Like some of her clients, she suddenly lacked the time and energy to work out the way she used to. She could manage no more than several 15-minute workouts per week, “but I actually felt like I got my minimum effective dose for that stage of my life,” she says. Many of us feel like we’re too busy for exercise. Others actively avoid it. But research shows that doing at least some exercise is important for longer, healthier lives without dementia, heart disease, diabetes, or cancer. Other advantages are reaped right away: we’re happier and more energetic on a daily basis. So, just how little exercise can you get away with, while still getting these benefits? Here’s how low you ca...