Move more, sit less, and get kids active as young as age 3, say new federal guidelines that stress any amount and any type of exercise helps health. The advice is the first update since the government's physical activity guidelines came out a decade ago, reports the AP. Since then, the list of benefits of exercise has grown, and there's more evidence to back things that were of unknown value before, such as short, high-intense workouts and taking the stairs instead of an elevator. "Doing something is better than doing nothing, and doing more is better than doing something," says Dr. Donald Lloyd-Jones, a preventive medicine expert at Northwestern University. Only 20% of Americans get enough exercise now, and the childhood obesity problem has prompted the push to aim younger to prevent poor health later in life. Other highlights from the guidelines: