Subtitles section Play video Print subtitles As a travel columnist, I am well-aware of what jet lag feels like, but what about what's happening in my head? This is Daniela: She's the expert, let's ask her. Jet lag is a chronobiological problem which is just a fancy way of saying your body's connection to the time of day. When we travel long distances, our circadian rhythm gets thrown out of whack, making it hard for your body to know when you should sleep and when you shouldn't. That's because our internal clock is suddenly different than our external clock. The shock doesn't just affect sleep. It also has an effect on your body temperature, blood pressure, plus when you get hungry and how hungry you are. Directly behind your eyes, there's a group of 20,000 nerve cells called the supra-chiasmatic nucleus, or the SCN, a.k.a. your body's master clock. It controls the production of melatonin, a hormone that helps make you sleepy. That's what's in the pills you see at any local pharmacy. When you move across time zones, your body's clock is still operating based on where you were, not where you are. According to research, the body's internal clock adapts slowly to abrupt changes. On average, it shifts approximately an hour or so per day for each hour of time zone change. That means, if I flew across three time zones from L.A. to New York, it might take about three days before I'm on New York time. Prolonged changes to your internal clock, like something you would see in shift workers, can cause some serious health problems. See these charts? Researchers are looking at how peoples' bodies react when they don't sleep during normal hours. Their blood pressure goes up, which is a risk factor for heart disease. It can also make the body more resistant to insulin, which increases the risk for diabetes. For many seasoned travelers, jet lag is frustrating, and it can contribute to serious health concerns. Many people just wanna take off and go, but it's important to have a strategy to improve your travels and your health.