Over winter break, I helped my best friend move across the country to California. The morning of the first day, leaving Indiana and heading toward our next stop in Kansas, we crossed from Eastern time into Central, a moment that made me think about time zones.
In order to talk about time zones, it’s important to explain some general properties of our planet. First, let’s get our facts straight. Earth is a sphere that moves through space in a couple simultaneous ways. It orbits around the sun, creating a year at each complete orbit, and it rotates about its axis, which creates a day with each rotation. Imagine spinning a basketball on your finger: The point at which your finger touches the ball creates an axis that the ball spins about, similar to Earth.
The continental United States is split into four standard time zones: Eastern, Central, Mountain and Pacific, and the world is divided into a total of 38 time zones. The theory behind the division is that the Earth rotates approximately 15 degrees every hour. Therefore, each time zone should have about 15 degrees longitude. In this way, if you adjust your clock appropriately for your time zone, the sun should be directly overhead at noon and will set at a predictable time, according to the season.
A longitudinal line is one that runs from the North Pole to the South Pole “vertically” on the Earth, and the one that indicates “zero” is called the prime meridian. This imaginary line runs through Greenwich, England, and also designates Greenwich Mean Time (GMT), which all other time zones are based on. Zones to the east are later hours and those to the west are earlier. Since Eastern Standard Time is five zones to the west, it’s designated at GMT-5. Therefore, 11 a.m. GMT is 6 a.m. EST.
So, at the end of my cross-country trip, I had to fly from Los Angeles back to my hometown in Maine. Over the course of three flights across four time zones, I made it back with a minor case of jet lag. I’ve joked about having jet lag in the past after driving all day; however, general tiredness is very different from jet lag.
When you travel quickly across time zones by airplane, although theoretically teleportation would also fit the bill, your circadian rhythms are synced to your original time zone and haven’t adjusted to your new one. Circadian rhythms, especially the ones that indicate tiredness, function in response to seeing sunlight and operate on a 24-hour cycle that dictates a person’s sleeping and eating behavior.
Since my friend and I had driven over the course of days, we gradually adjusted to the time changes. And driving west meant traveling “with” the sun, making a nine-hour day feel longer, especially because we felt hungry and tired at slightly different times with each passing time zone. However, when flying, I quickly lost several hours and probably didn’t drink as much water as I should have, making me more susceptible to altered sleep, fatigue and stomach problems. These jet lag symptoms were a direct response to a sudden time change that was much different from general travel exhaustion.
Therefore, the best way to reduce the effects of jet lag is to drink plenty of water and slowly adjust your schedule before you leave — important to remember if you’re traveling during spring break!