What is jetlag, anyway? Is it for real, or just an excuse to take an extra day off after that big vacation to recover? Every person has an internal clock. This small cluster of brain cells helps control the timing of biological functions — like alertness, or sleepiness. The rhythm of your body as determined by your internal clock is known as your circadian rhythms. Read more about circadian rhythms here. When your body clock is thrown out of sync — by travel to another time zone — you may feel fatigued, disoriented, confused and fuzzy-headed, and tense. You may … Continue reading →