Have you ever stopped to consider how many times a day you look at your phone? According to a recent report, smartphone users check their phones approximately 150 times a day, often while using another screen, like a TV or computer. That’s a lot of screen time! Dr. David Spiegel, director of the Stanford Center on Stress and Health, says constant exposure to light from screens causes people to shift away from natural sleep cycles, which could lead to fatigue and mental fogginess. Making an effort to limit your screen time each week––during the weekend, for example—will keep you sharp.