 This is Good Morning Northwest on 920 News Now. For many of us, especially if you're up in the early morning hours like we are, caffeine is a part of life. It's consumed daily by about 80% of adults worldwide. And dietician Julia Zapano with the Cleveland Clinic says it works by blocking receptors in your brain which promote sleep. Those receptors slow down the nerve activity which makes us feel tired. That helps explain the afternoon crash some may feel when their effects of the morning coffee start to wear off.