Question

Why might you experience jet lag if you travel across the United States on a plane? Predict which direction it would be more difficult to adjust to jet lag—when traveling from Hawaii to New York or New York to Hawaii. Support your answer with an example of each situation.

Short answer

Jet lag is worse when traveling from Hawaii to New York due to the need to advance the body clock, which is typically harder than delaying it.

Step-by-step solution

Understand Jet Lag

Jet lag is a temporary sleep disorder that occurs when a person's internal body clock is out of sync with the external environment due to traveling across multiple time zones. Symptoms can include fatigue, difficulty concentrating, and difficulty sleeping.

Analyze the Time Zone Changes

When traveling from Hawaii to New York, you move across 5 time zones, resulting in a forward shift in time (e.g., if it is 12 PM in Hawaii, it is 5 PM in New York). Traveling from New York to Hawaii causes a backward shift of the same magnitude.

Identify Travel Direction Impact

The direction of travel affects how your internal clock needs to adjust. Generally, traveling eastward (e.g., from Hawaii to New York) requires your body to advance its clock, which tends to be more challenging than delaying it, as when traveling westward (from New York to Hawaii).

Use Examples to Explain Adjustments

If you travel from Hawaii to New York, your body feels like it is earlier than the local time (e.g., 7 AM in Hawaii feels like 12 PM in New York), making it difficult to go to bed early and wake up early as needed. Conversely, traveling from New York to Hawaii, your body feels like it is later than the local time (e.g., 12 PM in New York feels like 7 AM in Hawaii), which often feels more manageable.

Conclude the Directional Difficulty

Based on how the body adjusts the internal clock, eastward travel (e.g., Hawaii to New York) usually results in more severe jet lag as compared to westward travel (e.g., New York to Hawaii) because it is more difficult for most people to force their bodies to sleep earlier than to stay up later.

Key concepts

Time Zones

Time zones are essential for standardizing time across different geographical locations around the world. They divide the Earth into 24 sections, each representing one hour of the day. When you travel across multiple time zones, your internal body might get confused because the time on your watch doesn't match the time your body feels it should be. For example, flying from Hawaii to New York means passing through five time zones. This results in the clock moving forward, meaning that when it’s noon in Hawaii, it’s already 5 PM in New York. This discrepancy between actual time and body’s perceived time can lead to what is known as jet lag.

Internal Clock

The internal clock, also known as the circadian rhythm, is a natural system that regulates sleepiness and alertness. This clock follows a roughly 24-hour schedule and is influenced by factors like light and temperature. When you travel quickly across time zones in a plane, your internal clock remains set to your original time zone, while the environment around you has changed. This can lead to symptoms of jet lag, as your body struggles to adjust to the new local time. Symptoms might include feeling tired during the day, being unable to sleep at night, and general fatigue.

Eastward Travel Adjustment

Traveling eastward, such as from Hawaii to New York, presents a special challenge for your internal clock. In this direction, you need to shift your schedule forward—essentially, you need to "skip ahead". Let’s say you leave Hawaii where it's 3 PM, and when you arrive in New York, it's already 8 PM. Your body still feels like it’s 3 PM, making it hard to sleep because you're not feeling tired yet. Adjusting eastward usually requires trying to sleep earlier, needing to trick your body into feeling sleepy before it's naturally ready. This often makes eastward travel adjustments more difficult to overcome.

Westward Travel Adjustment

In contrast to traveling east, going westward, like from New York to Hawaii, involves moving the clock backwards. This means delaying your schedule. Your internal clock will find this a bit easier to manage. Upon arrival, you might land at what feels like a later hour, even though it’s still daylight. Imagine flying west from New York where it’s noon and landing in Hawaii where it’s only 7 AM. Your body feels like it's lunch time, but local time suggests breakfast. Adjusting to westward journeys feels more natural to many people since you can stay awake longer, aligning sooner with the local time.