If your internal day runs about 24.2 hours, which travel shift gets a tiny natural assist?

Answer: The delay is easier

The delay is easier ✓ — A clock that naturally runs a bit long has a small built-in tendency to drift later. That makes westward travel, which asks you to delay sleep and wake, feel more like going with the grain. The 24.18-hour lab estimate sounds tiny, but repeated every day it helps explain why later bedtimes are often easier than earlier ones.

The advance is easier — Earlier waking is exactly the harder move for many travelers. To advance the clock, the body has to make its biological night arrive sooner than it was about to arrive on its own. That is why an eastbound trip can feel as if the destination is demanding bedtime before your internal evening has even started.

The miles dominate — Miles matter only when they translate into time-zone shifts; north-south long-haul travel can be exhausting without producing the same clock problem. For east-west travel, direction changes the required phase shift. The useful lesson is that jet lag is not just distance: the clock cares whether it must move earlier or later.